diff --git a/userguide/libnetpbm_ug.html b/userguide/libnetpbm_ug.html index 94d4fd4..bb1c77e 100644 --- a/userguide/libnetpbm_ug.html +++ b/userguide/libnetpbm_ug.html @@ -374,7 +374,7 @@ plain format. <H2 id="reference">Reference</h2> <p>The <a href="libnetpbm_image.html">Libnetpbm Netpbm Image -Processing Manual</a> describes the the <b>libnetpbm</b> functions for +Processing Manual</a> describes the <b>libnetpbm</b> functions for processing image data. <p>The <a href="libpm.html">Libnetpbm Utility Manual</a> diff --git a/userguide/pamfunc.html b/userguide/pamfunc.html index d158393..e0fe96a 100644 --- a/userguide/pamfunc.html +++ b/userguide/pamfunc.html @@ -57,7 +57,7 @@ output image. and bit string (such as and with 01001000). For the arithmetic functions, the function arguments and results are the fraction that a sample is of the maxval, i.e. normal interpretation of PAM tuples. But for the bit string -functions, the value is the the bit string whose value as a binary cipher is +functions, the value is the bit string whose value as a binary cipher is the sample value, and the maxval indicates the width of the bit string. <h4>Arithmetic functions</h4> diff --git a/userguide/pbmtog3.html b/userguide/pbmtog3.html index ee2bd6b..3b23517 100644 --- a/userguide/pbmtog3.html +++ b/userguide/pbmtog3.html @@ -77,7 +77,7 @@ You cannot specify both. <H2 id="history">HISTORY</H2> <p>Before Netpbm 10.79 (June 2017), there was a different program by the same -name in Netpbm, which was written by by Paul Haeberli +name in Netpbm, which was written by Paul Haeberli <<A HREF="mailto:paul@manray.sgi.com">paul@manray.sgi.com</A>> in 1989 and then modified extensively by others. diff --git a/userguide/ppmtompeg.html b/userguide/ppmtompeg.html deleted file mode 100644 index a1ce767..0000000 --- a/userguide/ppmtompeg.html +++ /dev/null @@ -1,1291 +0,0 @@ -<!DOCTYPE html PUBLIC "-//W3C//DTD HTML 3.2//EN"> -<HTML> -<HEAD> -<TITLE>Ppmtompeg User Manual</TITLE> -</HEAD> -<BODY> -<H1>Ppmtompeg</H1> -Updated: 23 July 2006 -<BR> -<A HREF="#index">Table Of Contents</A> - -<H2>NAME</H2> -ppmtompeg - encode an MPEG-1 bitstream - -<H2 id="synopsis">SYNOPSIS</H2> - -<B>ppmtompeg</B> -[<I>options</I>] -<I>parameter-file</I> - -<H2 id="description">DESCRIPTION</H2> - -<p>This program is part of <a href="index.html">Netpbm</a>. - -<P><B>ppmtompeg</B> produces an MPEG-1 video stream. MPEG-1 is the -first great video compression method, and is what is used in Video CDs -(VCD). <b>ppmtompeg</b> originated in the year 1995. DVD uses a more -advanced method, MPEG-2. There is an even newer method called MPEG-4 -which is also called Divx. I don't know where one finds that used. - -<p>There's technically a difference between a compression method for -video and an actual file (stream) format for a movie, and I don't know -if it can be validly said that the format of the stream -<b>ppmtompeg</b> produces is MPEG-1. - -<p>Mencoder from the <a href="http://www.mplayerhq.hu">Mplayer -package</a> is probably superior for most video format generation -needs, if for no other reason than that it is more popular. - -<p>The programming library <a href="http://pm2v.free.fr"><b>PM2V</b></a> -generates MPEG-2 streams. - -<p>Use <a href="http://www.mplayerhq.hu">Mplayer</a> (not part of Netpbm) -to do the reverse conversion: to create a series of PNM files from an MPEG -stream. - -<p><i>param_file</i> is a parameter file which includes a list of -input files and other parameters. The file is described in detail -below. - -<P>To understand this program, you need to understand something about -the complex MPEG-1 format. One source of information about this -standard format is the section Introduction to MPEG in the <a -href="http://www.faqs.org/faqs/compression-faq">Compression FAQ</a>. - -<H2 id="options">OPTIONS</H2> - -<p>The <b>-gop</b>, <b>-combine_gops</b>, <b>-frames</b>, and -<b>-combine_frames</b> options are all mutually exclusive. - -<DL COMPACT> -<DT><B>-stat stat_file</B> - -<DD>This option causes <b>ppmtompeg</b> to append the statistics that -it write to Standard Output to the file <I>stat_file</I> as well. The -statistics use the following abbreviations: bits per block (bpb), bits -per frame (bpf), seconds per frame (spf), and bits per second (bps). - -<p>These statistics include how many I, P, and B frames there were, -and information about compression and quality. - - -<DT><B>-quiet</b> <i>num_seconds</i> - -<DD> causes <b>ppmtompeg</b> not to report remaining time more often -than every <i>num_seconds</i> seconds (unless the time estimate rises, -which will happen near the beginning of the run). A negative value -tells <b>ppmtompeg</b> not to report at all. 0 is the default -(reports once after each frame). Note that the time remaining is an -estimate and does not take into account time to read in frames. - -<DT><B>-realquiet</B> <DD> causes <b>ppmtompeg</b> to run silently, -with the only screen output being errors. Particularly useful when -reading input from stdin. - -<DT> -<B>-no_frame_summary</B> - -<DD> This option prevents <b>ppmtompeg</b> from printing a summary -line for each frame - -<DT><B>-float_dct</B> - -<DD> forces <b>ppmtompeg</b> to use a more accurate, yet more -computationally expensive version of the DCT. - -<DT><B>-gop</b> <i>gop_num</i> -<DD> -causes <b>ppmtompeg</b> to encode only the numbered GOP (first GOP is 0). The -parameter file is the same as for normal usage. The output file will be -the normal output file with the suffix <b>.gop.</b><i>gop_num</i>. -<b>ppmtompeg</b> does not output any sequence information. - -<DT><B>-combine_gops</B> - -<DD> causes <b>ppmtompeg</b> simply to combine some GOP files into a -single MPEG output stream. <b>ppmtompeg</b> inserts a sequence header -and trailer. In this case, the parameter file needs only to contain -the SIZE value, an output file, and perhaps a list of input GOP -files (see below). - -If you don't supply a list of input GOP files is used, then -<b>ppmtompeg</b> assumes you're using the same parameter file you used -when you created the input (with the <b>-gop</b> option) and -calculates the corresponding gop filenames itself. If this is not the -case, you can specify input GOP files in the same manner as normal -input files -- except instead of using INPUT_DIR, INPUT, and -END_INPUT, use GOP_INPUT_DIR, GOP_INPUT, and GOP_END_INPUT. If no -input GOP files are specified, then the default is to use the output -file name with suffix <b>.gop.</b><i>gop_num</i>, with <i>gop_num</i> -starting from 0, as the input files. - -<p>Thus, unless you're mixing and matching GOP files from different -sources, you can simply use the same parameter file for creating the -GOP files (<b>-gop</b>) and for later turning them into an MPEG stream -(<b>-combine_gops</b>). - - -<DT><B>-frames <i>first_frame</i> <i>last_frame</i></B> - -<DD>This option causes <b>ppmtompeg</b> to encode only the frames numbered -<i>first_frame</i> to <i>last_frame</i>, inclusive. The parameter -file is the same as for normal usage. The output will be placed in -separate files, one per frame, with the file names being the normal -output file name with the suffix <b>.frame.</b><i>frame_num</i>. No -GOP header information is output. (Thus, the parameter file need not -include the GOP_SIZE value) - -<p>Use <b>ppmtompeg -combine_frames</b> to combine these frames later into -an MPEG stream. - - -<DT><B>-combine_frames</B> - -<DD> This option causes <b>ppmtompeg</b> simply to combine some -individual MPEG frames (such as you might have created with an earlier -run of <b>ppmtompeg -frames</b>) into a single MPEG stream. Sequence -and GOP headers are inserted appropriately. In this case, the -parameter file needs to contain only the SIZE value, the GOP_SIZE -value, an output file, and perhaps a list of frame files (see below). - -<p>The parameter file may specify input frame files in the same manner -as normal input files -- except instead of using INPUT_DIR, INPUT, and -END_INPUT, use FRAME_INPUT_DIR, FRAME_INPUT, and FRAME_END_INPUT. If -no input frame files are specified, then the default is to use the -output file name with suffix <b>.frame.</b><i>frame_num</i>, with -<i>frame_num</i> starting from 0, as the input files. - - - -<DT><B>-nice</B> - -<DD>This option causes <b>ppmtompeg</b> to run any remote processes -"nicely," i.e. at low priority. (This is relevant only if you are -running <b>ppmtompeg</b> in parallel mode. Otherwise, there are no -remote processes). See 'man nice.' - -<DT><B>-max_machines <i>num_machines</i></B> - -<DD>This option causes <b>ppmtompeg</b> to use no more than -<i>num_machines</i> machines as slaves for use in parallel encoding. - -<DT><B>-snr</B> - -<DD>This option causes <b>ppmtompeg</b> to include the signal-to-noise -ratio in the reported statistics. Prints SNR (Y U V) and peak SNR (Y -U V) for each frame. In summary, prints averages of luminance only -(Y). SNR is defined as 10*log(variance of original/variance of -error). Peak SNR is defined as 20*log(255/RMSE). Note that -<b>ppmtompeg</b> runs a little slower when you use this option. - -<DT><B>-mse</B> - -<DD>This option causes <b>ppmtompeg</b> to report the mean squared -error per block. It also automatically reports the quality of the -images, so there is no need to specify <b>-snr</b> then. - -<DT><B>-bit_rate_info</b> <i>rate_file</i> - -<DD> This option makes <b>ppmtompeg</b> write bit rate information -into the file <i>rate_file</i>. Bit rate information is bits per frame, and -also bits per I-frame-to-I-frame. - -<DT><B>-mv_histogram</B> - -<DD> This option causes <b>ppmtompeg</b> to print a histogram of the -motion vectors as part of statistics. There are three histograms -- -one for P frame, one for forward B frame, and one for backward B frame -motion vectors. - -<p>The output is in the form of a matrix, each entry corresponding to one -motion vector in the search window. The center of the matrix -represents (0,0) motion vectors. - -<dt><b>-debug_sockets</b> - -<dd>This option causes <b>ppmtompeg</b> to print to Standard Output -messages that narrate the communication between the machines when you run -<b>ppmtompeg</b> in <a href="#parallel">parallel mode</a>. - -<dt><b>-debug_machines</b> - -<dd>This option causes <b>ppmtompeg</b> to print to Standard Output -messages that narrate the progress of the conversion on the various -machines when you run <b>ppmtompeg</b> in <a href="#parallel">parallel -mode</a>. - -</DL> - -<H2 id="parmfile">PARAMETER FILE</H2> - -<P>The parameter file <strong>must</strong> contain the following -lines (except when using the <b>-combine_gops</b> or <b>-combine_frames</b> -options): - -<DL COMPACT> - -<DT><B>PATTERN</b> <i>pattern</i> - -<DD>This statement specifies the pattern (sequence) of I frames, P frames, -and B frames. <i>pattern</i> is just a sequence of the letters I, P, and -B with nothing between. Example: - -<pre> - PATTERN IBBPBBPBBPBBPBB -</pre> - -<p>See <a href="#ipb">I Frames, P Frames, B Frames</a>. - -<DT><B>OUTPUT</b> <i>output file</i> -<DD>This names the file where the output MPEG stream goes. - -<DT><B>INPUT_DIR</b> <i>directory</i> - -<DD>This statement tells where the input images (frames) come from. -If each frame is in a separate file, <i>directory</i> is the directory -where they all are. You may use <b>.</b> to refer to the current -directory. A null <i>directory</i> refers to the root directory of the -system file tree. - -<p>To have <b>ppmtompeg</b> read all the frames serially from Standard -Input, specify -<pre> - INPUT_DIR stdin -</pre> - -<DT><B>INPUT</b> -<DD> -This line must be followed by a list of the input files (in display order) -and then the line <B>END_INPUT</B>. - -<p>There are three types of lines between INPUT and END_INPUT. First, -a line may simply be the name of an input file. Second, the line -may be of the form <i>single_star_expr</i> -<b>[</b><i>x</i><b>-</b><i>y</i><b>]</b>. -<i>single_star_expr</i> can have a single <b>*</b> in it. It is -replaced by all the numbers between x and y inclusive. So, for -example, the line <b>tennis*.ppm [12-15]</b> refers to the files -tennis12.ppm, tennis13.ppm, tennis14.ppm, tennis15.ppm. - -<p>Uniform zero-padding occurs, as well. For example, the line -<b>football.*.ppm [001-130]</b> refers to the files football.001.ppm, -football.002.ppm, ..., football.009.ppm, football.010.ppm, ..., -football.130.ppm. - -<p>The third type of line is: <i>single_star_expr</i> -<b>[</b><i>x</i><b>-</b><i>y</i><b>+</b><i>s</i><b>]</b>, where the -line is treated exactly as above, except that we skip by <i>s</i>. Thus, the -line <b>football.*.ppm [001-130+4]</b> refers to the files -football.001.ppm, football.005.ppm, football.009.ppm, -football.013.ppm, etc. - -<p>Furthermore, a line may specify a shell command to execute to -generate lines to be interpreted as described above, as if those lines -were in the parameter file instead. Use back ticks, like in the -Bourne Shell, like this: - -<pre> - `cat myfilelist` -</pre> - -<p> -If input is from Standard Input (per the <b>INPUT_DIR</b> statement), -<b>ppmtompeg</b> ignores the <B>INPUT</b>/<b>END_INPUT</b> block, but -it still must be present. - -<DT><b>BASE_FILE_FORMAT</b> {<b>PPM</b> | <b>PNM</b> | <b>YUV</b> | - <b>JPEG</b> | <b>JMOVIE</b>} - -<DD><B>ppmtompeg</b> must convert all input files to one of the -following formats as a first step of processing: PNM, YUV, JPEG(v4), -or JMOVIE. (The conversion may be trivial if your input files are -already in one of these formats). This line specifies which of the -four formats. PPM is actually a subset of PNM. The separate -specification is allowed for backward compatibility. Use PNM instead -of PPM in new applications. - -<DT><b>INPUT_CONVERT</b> <i>conversion_command</i> - -<DD>You must specify how to convert a file to the base file format. -If no conversion is necessary, then you would just say: - - <pre> - INPUT_CONVERT * - </pre> - -<p>Otherwise, <i>conversion_command</i> is a shell command that causes -an image in the format your specified with <B>BASE_FILE_FORMAT</b> to -be written to Standard Output. <b>ppmtompeg</b> executes the command -once for each line between <b>INPUT</b> and <b>END_INPUT</b> (which is -normally, but not necessarily, a file name). In the conversion -command, <b>ppmtompeg</b> replaces each '*' with the contents of that -line. - - If you had a bunch of gif files, you might say: - <pre> - INPUT_CONVERT giftopnm * - </pre> - - If you have a bunch of separate a.Y, a.U, and a.V files (where - the U and V have already been subsampled), then you might say: - - <pre> - INPUT_CONVERT cat *.Y *.U *.V - </pre> - -<p>Input conversion is not allowed with input from stdin, so use - - <pre> - INPUT_CONVERT * - </pre> - -as described above. - -<DT><b>SIZE</b> <i>width</i><b>x</b><i>height</i> - -<dd> - -<p><i>width</i> and <i>height</i> are the width and height of each -frame in pixels. - -<p>When <b>ppmtompeg</b> can get this information from the input image -files, it ignores the <b>SIZE</b> parameter and you may omit it. - -<p>When the image files are in YUV format, the files don't contain -dimension information, so <b>SIZE</b> is required. - -<p>When <b>ppmtompeg</b> is running in parallel mode, not all of the -processes in the network have access to the image files, so -<b>SIZE</b> is required and must give the same dimensions as the -input image files. - -<DT><b>YUV_SIZE</b> <i>width</i><b>x</b><i>height</i> - -<dd>This is an obsolete synonym of <b>SIZE</b>. - -<DT><b>YUV_FORMAT</B> {<b>ABEKAS</b> | <b>PHILLIPS</b> | <b>UCB</B> | - <b>EYUV</b> | <i>pattern</i>} - -<DD>This is meaningful only when <b>BASE_FILE_FORMAT</b> specifies -YUV format, and then it is required. It specifies the sub-format of -the YUV class. - - -<DT><b>GOP_SIZE</b> <i>n</i> - -<DD><i>n</i> is the number of frames in a Group of Pictures. Except that -because a GOP must start with an I frame, <b>ppmtompeg</b> makes a GOP as -much longer than <i>n</i> as it has to to make the next GOP start with an -I frame. - -<p>Normally, it makes sense to make your GOP size a multiple of your -pattern length (the latter is determined by the PATTERN parameter file -statement). - -<p>See <a href="#gop">Group Of Pictures</a>. - -<DT><b>SLICES_PER_FRAME</b> <i>n</i> -<dd><i>n</i> is roughly the number of slices per frame. Note, at -least one MPEG player may complain if slices do not start at the left -side of an image. To ensure this does not happen, make sure the -number of rows is divisible by SLICES_PER_FRAME. - -<DT><b>PIXEL</b> {<b>FULL</b> | <b>HALF</b>} - -<dd>use half-pixel motion vectors, or just full-pixel ones It is -usually important that you use half-pixel motion vectors, because it -results in both better quality and better compression. - - -<DT><b>RANGE</b> <i>n</i> -<dd>Use a search range of <i>n</i> pixels in each of the four directions -from a subject pixel. (So the search window is a square <i>n</i>*2 pixels -on a side). - -<DT><b>PSEARCH_ALG</b> {<b>EXHAUSTIVE</B> | <b>TWOLEVEL</b> | - <b>SUBSAMPLE</b> | <b>LOGARITHMIC</b>} - -<dd>This statement tells <b>ppmtompeg</b> what kind of search - technique (algorithm) to use for P frames. You select the desired - combination of speed and compression. <b>EXHAUSTIVE</b> gives the - best compression, but <b>LOGARITHMIC</B> is the fastest. - <B>TWOLEVEL</B> is an exhaustive full-pixel search, followed by a - local half- pixel search around the best full-pixel vector (the - PIXEL option is ignored for this search technique). - -<DT><b>BSEARCH_ALG</b> {<b>SIMPLE</B> | <B>CROSS2</B> | <B>EXHAUSTIVE</B>} - -<dd>This statement tells <b>ppmtompeg</b> what kind of search - technique (algorithm) to use for B frames. <b>SIMPLE</B> means - find best forward and backward vectors, then interpolate. - <B>CROSS2</B> means find those two vectors, then see what backward - vector best matches the best forward vector, and vice versa. - <b>EXHAUSTIVE</b> does an n-squared search and is - <em>extremely</em> slow in relation to the others (<b>CROSS2</b> - is about half as fast as <b>SIMPLE</B>). - -<DT><b>IQSCALE</b> <i>n</i> -<dd>Use <i>n</i> as the qscale for I frames. - See <a href="#qscale">Qscale</a>. - -<DT><b>PQSCALE</b> <i>n</i> -<dd>Use <i>n</i> as the qscale for P frames. - See <a href="#qscale">Qscale</a>. - -<DT><b>BQSCALE</b> <i>n</i> -<dd>Use <i>n</i> as the qscale for B frames. - See <a href="#qscale">Qscale</a>. - -<DT><b>REFERENCE_FRAME</b> {<B>ORIGINAL</B> | <b>DECODED</b>} <dd>This -statement determines whether <b>ppmtompeg</b> uses the original images -or the decoded images when computing motion vectors. Using decoded -images is more accurate and should increase the playback quality of -the output, but it makes the encoding take longer and seems to give -worse compression. It also causes some complications with parallel -encoding. (see the section on parallel encoding). One thing you can -do as a trade-off is select <b>ORIGINAL</b> here, and lower the -qscale (see <b>QSCALE</b> if the quality is not good enough. - -<table border="1" cellpadding="5" cellspacing="0" -summary="comparison of original to decoded"> - <caption>Original or Decoded? (Normalized)</caption> -<?makeman r c c c c c. ?> -<?makeman _ ?> - <tr align="center" bgcolor="#CCCCCC"> - <th>Reference</th> - <th>Compression</th> - <th>Speed</th> - <th>Quality I</th> - <th>Quality P</th> - <th>Quality B</th> - </tr> - <tr> - <td align="right">Decoded</td> - <td align="center">1000</td> - <td align="center">1000</td> - <td align="center">1000</td> - <td align="center">969</td> - <td align="center">919</td> - </tr> - <tr> - <td align="right">Original</td> - <td align="center">885</td> - <td align="center">1373</td> - <td align="center">1000</td> - <td align="center">912</td> - <td align="center">884</td> - </tr> - </table> - - - -</dl> - -<p>The following lines are optional: - -<DL> - -<DT><B>FORCE_ENCODE_LAST_FRAME</B> - -<dd>This statement is obsolete. It does nothing. - -<p>Before Netpbm 10.26 (January 2005), <b>ppmtompeg</b> would drop -trailing B frames from your movie, since a movie can't end with a B -frame. (See <a href="#ipb">I Frames, P Frames, B Frames</a>. -You would have to specify <b>FORCE_ENCODE_LAST_FRAME</b> to stop -that from happening and get the same function that <b>ppmtompeg</b> -has today. - - -<DT><b>NIQTABLE</b> - -<dd>This statement specifies a custom non-intra quantization table. -If you don't specify this statement, <b>ppmtompeg</b> uses a default -non-intra quantization table. - -<p> -The 8 lines immediately following <b>NIQTABLE</b> specify the quantization -table. Each line defines a table row and consists of 8 integers, -whitespace-delimited, which define the table columns. - -<DT><B>IQTABLE</b> - -<dd>This is analogous to NIQTABLE, but for the intra quantization table. - -<DT><b>ASPECT_RATIO</b> <i>ratio</i> - -<dd>This statement specifies the aspect ratio for <b>ppmtompeg</b> to -specify in the MPEG output. I'm not sure what this is used for. - -<p><i>ratio</i> must be 1.0, 0.6735, 0.7031, 0.7615, 0.8055, 0.8437, -0.8935, 0.9157, 0.9815, 1.0255, 1.0695, 1.0950, 1.1575, or 1.2015. - -<DT><b>FRAME_RATE</b> <i>rate</i> -<dd>This specifies the frame rate for <b>ppmtompeg</b> to specify in the -MPEG output. Some players use this value to determine the playback rate. - -<p><i>rate</i> must be 23.976, 24, 25, 29.97, 30, 50, 59.94, or 60. - -<DT><b>BIT_RATE</b> <i>rate</i> -<DD>This specifies the bit rate for Constant Bit Rate (CBR) encoding. - -<p><i>rate</i> must be an integer. - -<DT><b>BUFFER_SIZE</b> <i>size</i> - -<dd>This specifies the value -<b>ppmtompeg</b> is to specify in the MPEG output for the Video -Buffering Verifier (VBV) buffer size needed to decode the sequence. - -<p>A Video Verifying Buffer is a buffer in which a decoder keeps the -decoded bits in order to match the uneven speed of the decoding with -the required constant playback speed. - -<p>As <b>ppmtompeg</b> encodes the image, it simulates the decoding -process in terms of how many bits would be in the VBV as each frame gets -decoded, assuming a VBV of the size you indicate. - -<P>If you specify the <b>WARN_VBV_UNDERFLOW</b> statement, -<b>ppmtompeg</b> issues a warning each time the simulation underflows -the buffer, which suggests that an underflow would occur on playback, -which suggests the buffer is too small. - -<P>If you specify the <b>WARN_VBV_OVERFLOW</b> statement, -<b>ppmtompeg</b> issues a warning each time the simulation overflows -the buffer, which suggests that an overflow would occur on playback, -which suggests the buffer is too small. - -<DT><B>WARN_VBV_UNDERFLOW</B> -<DT><B>WARN_VBV_OVERFLOW</B> - -<dd>See <b>BUFFER_SIZE</b>. - -<p>These options were new in Netpbm 10.26 (January 2005). Before that, -<b>ppmtompeg</b> issued the warnings always. - -</DL> - - -The following statements apply only to parallel operation: - -<DL> - -<DT><b>PARALLEL</b> - -<dd>This statement, paired with <b>END PARALLEL</B>, is what causes -<b>ppmtompeg</b> to operate in parallel mode. See <a -href="#parallel">Parallel Operation</a>. - -<dt><b>END PARALLEL</b> - -<DD>This goes with <b>PARALLEL</b>. - -<DT><b>PARALLEL_TEST_FRAMES</b> <i>n</i> - -<dd>The master starts off by measuring each slave's speed. It does -this by giving each slave <i>n</i> frames to encode and noting how -long the slave takes to finish. These are not just test frames, -though -- they're real frames and the results become part of the -output. -<b>ppmtompeg</b> is old and measures time in undivided seconds, so -to get useful timings, specify enough frames that it will take at -least 5 seconds to process them. The default is 10. - -<p>If you specify <b>FORCE_I_ALIGN</b>, <b>ppmtompeg</b> will increase -the test frames value enough to maintain the alignment. - -<p>If there aren't enough frames for every slave to have the indicated -number of test frames, <b>ppmtompeg</b> will give some slaves fewer. - - -<DT><b>PARALLEL_TIME_CHUNKS</b> <i>t</i> - -<dd>When you specify this statement, the master attempts to feed work -to the slaves in chunks that take <i>t</i> seconds to process. It uses -the speed measurement it made when it started up (see PARALLEL_TEST_FRAMES) -to decide how many frames to put in the chunk. This statement obviously -doesn't affect the first batch of work sent to each slave, which is the -one used to measure the slave's speed. - -<p>Smaller values of <i>t</i> increase communication, but improve load -balancing. The default is 30 seconds. - -<p>You may specify only one of PARALLEL_TIME_CHUNKS, PARALLEL_CHUNK_TAPER, -and PARALLEL_PERFECT. PARALLEL_CHUNK_TAPER is usually best. - -<DT><b>PARALLEL_CHUNK_TAPER</b> - -<DD>When you specify this statement, the master distributes work like -with PARALLEL_TIME_CHUNKS, except that the master chooses the number -of seconds for the chunks. It starts with a large number and, as it -gets closer to finishing the job, reduces it. That way, it reduces -scheduling overhead when precise scheduling isn't helpful, but still -prevents a slave from finishing early after all the work has already -been handed out to the other slaves, and then sitting idle while -there's still work to do. - -<p>You may specify only one of PARALLEL_TIME_CHUNKS, PARALLEL_CHUNK_TAPER, -and PARALLEL_PERFECT. PARALLEL_CHUNK_TAPER is usually best. - - -<DT><b>PARALLEL_PERFECT</b> - -<dd>If this statement is present, <b>ppmtompeg</b> schedules on the -assumption that each machine is about the same speed. The master will -simply divide up the frames evenly between the slaves -- each -slave gets the same number of frames. If some slaves are faster than -others, they will finish first and remain idle while the slower slaves -continue. - -<p>This has the advantage of minimal scheduling overhead. Where slaves -have different speeds, though, it makes inefficient use of the fast -ones. Where slaves are the same speed, it also has the disadvantage -that they all finish at the same time and feed their output to the -single Combine Server in a burst, which makes less efficient use of -the Combine Server and thus can increase the total elapsed time. - -<p>You may specify only one of PARALLEL_TIME_CHUNKS, PARALLEL_CHUNK_TAPER, -and PARALLEL_PERFECT. PARALLEL_CHUNK_TAPER is usually best. - -<DT><b>RSH</b> <i>remote_shell_command</i> - -<DD><b>ppmtompeg</b> executes the shell command -<i>remote_shell_command</i> to start a process on another machine. -The default command is <b>rsh</b>, and whatever command you specify -must have compatible semantics. <b>ssh</b> is usually compatible. -The command <b>ppmtompeg</b> uses is one like this: -<b>ssh remote.host.com -l username shellcommand</b>. - -<p>Be sure to set up <b>.rhosts</b> files or SSH key authorizations -where needed. Otherwise, you'll have to type in passwords. - -<p>On some HP machines, <b>rsh</b> is the restricted shell, and you want -to specify <b>remsh</b>. - -<DT><b>FORCE_I_ALIGN</b> - -<dd>This statement forces each slave to encode a chunk of frames which -is a multiple of the pattern length (see <b>PATTERN</b>). Since the -first frame in any pattern is an I frame, this forces each chunk -encoded by a slave to begin with an I frame. - -<p>This document used to say there was an argument to -<b>FORCE_I_ALIGN</b> which was the number of frames <b>ppmtompeg</b> -would use (and was required to be a multiple of the pattern length). -But <b>ppmtompeg</b> has apparently always ignored that argument, and -it does now. - -<DT><B>KEEP_TEMP_FILES</B> - -<dd>This statement causes <b>ppmtompeg</b> not to delete the temporary -files it uses to transmit encoded frames to the combine server. This -means you will be left with a file for each frame, the same as you -would get with the <b>-frames</b> option. - -<p>This is mostly useful for debugging. - -<p>This works only if you're using a shared filesystem to communicate -between the servers. - -<p>This option was new in Netpbm 10.26 (January 2005). - -</DL> - - -<H3>Parameter File Notes</h3> - -<P> If you use the <b>-combine_gops</b> option, then you need to specify -only the SIZE and OUTPUT values in the parameter file. In -addition, the parameter file may specify input GOP files in the same -manner as normal input files -- except instead of using INPUT_DIR, -INPUT, and END_INPUT, use GOP_INPUT_DIR, GOP_INPUT, and GOP_END_INPUT. -If you specify no input GOP files, then <b>ppmtompeg</b> uses by default the -output file name with suffix <b>.gop.</b><i>gop_num</i>, with <i>gop_num</i> -starting from 0, as the input files. - -<p>If you use the <b>-combine_frames</b> option, then you need to -specify only the SIZE, GOP_SIZE, and OUTPUT values in the -parameter file. In addition, the parameter file may specify input -frame files in the same manner as normal input files -- except instead -of using INPUT_DIR, INPUT, and END_INPUT, use FRAME_INPUT_DIR, -FRAME_INPUT, and FRAME_END_INPUT. If no input frame files are -specified, then the default is to use the output file name with suffix -<b>.frame.</b><i>frame_num</i>, with <i>frame_num</i> starting from 0, -as the input files. - -<p>Any number of spaces and tabs may come between each option and value. Lines -beginning with <b>#</b> are ignored. Any other lines are ignored except for -those between INPUT and END_INPUT. This allows you to use the same -parameter file for normal usage and for <b>-combine_gops</b> and -<b>-combine_frames</b>. - -<P>The file format is case-sensitive so all keywords should be in -upper case. - -<P>The statements may appear in any order, except that the order within -a block statement (such as INPUT ... END INPUT) is significant. - -<P><b>ppmtompeg</b> is prepared to handle up to 16 B frames between -reference frames when encoding with input from stdin. (To build a -modified <b>ppmtompeg</b> with a higher limit, change the constant -B_FRAME_RUN in frame.c and recompile). - -<H2 id="general">GENERAL USAGE INFORMATION</H2> - -<H3 id="qscale">Qscale</h3> - -<p>The quantization scale values (qscale) give a trade-off between -quality and compression. Using different Qscale values has very little -effect on speed. The qscale values can be set separately for I, P, and -B frames. - -<p>You select the qscale values with the <B>IQSCALE</b>, -<b>PQSCALE</b>, and <b>BSCALE</b> parameter file statements. - -<p>A qscale value is an integer from 1 to 31. Larger numbers give -better compression, but worse quality. In the following, the quality -numbers are peak signal-to-noise ratio, defined as: -<img src="ppmtompeg-snr.gif" alt="signal-to-noise formula" height="52" width="302"> -where MSE is the mean squared error. - - -<p>Flower garden tests: - -<table border="1" cellpadding="5" cellspacing="0" summary="Qscale vs Quality"> - <caption>Qscale vs Quality</caption> -<?makeman r r r r. ?> -<?makeman _ ?> - <tr align="center"> - <th>Qscale</th> - <th>I Frames</th> - <th>P Frames</th> - <th>B Frames</th> - </tr> - <tr> - <td align="right">1</td> - <td align="right">43.2</td> - <td align="right">46.3</td> - <td align="right">46.5</td> - </tr> - <tr> - <td align="right">6</td> - <td align="right">32.6</td> - <td align="right">34.6</td> - <td align="right">34.3</td> - </tr> - <tr> - <td align="right">11</td> - <td align="right">28.6</td> - <td align="right">29.5</td> - <td align="right">30.0</td> - </tr> - <tr> - <td align="right">16</td> - <td align="right">26.3</td> - <td align="right">26.8</td> - <td align="right">28.6</td> - </tr> - <tr> - <td align="right">21</td> - <td align="right">24.7</td> - <td align="right">25.0</td> - <td align="right">27.9</td> - </tr> - <tr> - <td align="right">26</td> - <td align="right">23.5</td> - <td align="right">23.9</td> - <td align="right">27.5</td> - </tr> - <tr> - <td align="right">31</td> - <td align="right">22.6</td> - <td align="right">23.0</td> - <td align="right">27.3</td> - </tr> -</table> - -<table border="1" cellpadding="5" cellspacing="0" -summary="Qscale vs Compression"> - <caption>Qscale vs Compression</caption> -<?makeman r r r r. ?> -<?makeman _ ?> - <tr align="center"> - <th>Qscale</th> - <th>I Frames</th> - <th>P Frames</th> - <th>B Frames</th> - </tr> - <tr> - <td align="right">1</td> - <td align="right">2</td> - <td align="right">2</td> - <td align="right">2</td> - </tr> - <tr> - <td align="right">6</td> - <td align="right">7</td> - <td align="right">10</td> - <td align="right">15</td> - </tr> - <tr> - <td align="right">11</td> - <td align="right">11</td> - <td align="right">18</td> - <td align="right">43</td> - </tr> - <tr> - <td align="right">16</td> - <td align="right">15</td> - <td align="right">29</td> - <td align="right">97</td> - </tr> - <tr> - <td align="right">21</td> - <td align="right">19</td> - <td align="right">41</td> - <td align="right">173</td> - </tr> - <tr> - <td align="right">26</td> - <td align="right">24</td> - <td align="right">56</td> - <td align="right">256</td> - </tr> - <tr> - <td align="right">31</td> - <td align="right">28</td> - <td align="right">73</td> - <td align="right">330</td> - </tr> -</table> - - -<h3>Search Techniques</h3> - -<p>There are several different motion vector search techniques -available. There are different techniques available for P frame -search and B frame search. Using different search techniques present -little difference in quality, but a large difference in compression -and speed. - -<p>There are 4 types of P frame search: Exhaustive, TwoLevel, -SubSample, and Logarithmic. - -<p>There are 3 types of B frame search: Exhaustive, Cross2, and -Simple. - -The recommended search techniques are TwoLevel and Logarithmic for -P frame search, and Cross2 and Simple for B frame search. Here are -some numbers comparing the different search methods: - -<table border="1" cellpadding="5" cellspacing="0" -summary="P frame motion vector search"> - <caption>P frame Motion Vector Search (Normalized)</caption> -<?makeman r c c c. ?> -<?makeman _ ?> - <tr align="center"> - <th>Technique</th> - <th>Compression<a href="#smallbetter"><sup>1</sup></a></th> - <th>Speed <a href="#largefaster"><sup>2</sup></a></th> - <th>Quality <a href="#largebetter"><sup>3</sup></a></th> - </tr> - <tr> - <td align="right">Exhaustive</td> - <td align="center">1000</td> - <td align="center">1000</td> - <td align="center">1000</td> - </tr> - <tr> - <td align="right">SubSample</td> - <td align="center">1008</td> - <td align="center">2456</td> - <td align="center">1000</td> - </tr> - <tr> - <td align="right">TwoLevel</td> - <td align="center">1009</td> - <td align="center">3237</td> - <td align="center">1000</td> - </tr> - <tr> - <td align="right">Logarithmic</td> - <td align="center">1085</td> - <td align="center">8229</td> - <td align="center">998</td> - </tr> -</table> - -<table border="1" cellpadding="5" cellspacing="0" -summary="B frame motion vector search"> - <caption>B frame Motion Vector Search (Normalized)</caption> -<?makeman r c c c. ?> -<?makeman _ ?> - <tr align="center"> - <th>Technique</th> - <th>Compression<a href="#smallbetter"><sup>1</sup></a></th> - <th>Speed<a href="#largefaster"><sup>2</sup></a></th> - <th>Quality<a href="#largebetter"><sup>3</sup></a></th> - </tr> - <tr> - <td align="right">Exhaustive</td> - <td align="center">1000</td> - <td align="center">1000</td> - <td align="center">1000</td> - </tr> - <tr> - <td align="right">Cross2</td> - <td align="center">975</td> - <td align="center">1000</td> - <td align="center">996</td> - </tr> - <tr> - <td align="right">Simple</td> - <td align="center">938</td> - <td align="center">1765</td> - <td align="center">991</td> - </tr> -</table> - -<a name="smallbetter"> </a><sup>1</sup>Smaller numbers are better -compression. - -<a name="largefaster"> </a><sup>2</sup>Larger numbers mean faster -execution. - -<a name="largebetter"> </a><sup>3</sup>Larger numbers mean better quality. - -<p>For some reason, Simple seems to give better compression, but it -depends on the image sequence. - -<p>Select the search techniques with the <B>PSEARCH_ALG</B> and -<B>BSEARCH_ALG</b> parameter file statements. - - -<a name="gop"></a> -<h3>Group Of Pictures (GOP)</h3> - -<p>A Group of Pictures (GOP) is a roughly independently decodable -sequence of frames. An MPEG video stream is made of one or more -GOP's. You may specify how many frames should be in each GOP with the -<b>GOP_SIZE</b> parameter file statement. A GOP always starts with an -I frame. - -<p>Instead of encoding an entire sequence, you can encode a single -GOP. To do this, use the <b>-gop</b> command option. You can later -join the resulting GOP files at any time by running <b>ppmtompeg</b> -with the <b>-combine_gops</b> command option. - - -<h3>Slices</h3> - -<p>A slice is an independently decodable unit in a frame. It can be -as small as one macroblock, or it can be as big as the entire frame. -Barring transmission error, adding slices does not change quality or -speed; the only effect is slightly worse compression. More slices are -used for noisy transmission so that errors are more recoverable. Since -usually errors are not such a problem, we usually just use one slice -per frame. - -<p>Control the slice size with the <B>SLICES_PER_FRAME</B> parameter -file statement. - -<p>Some MPEG playback systems require that each slice consist of whole -rows of macroblocks. If you are encoding for this kind of player, if -the height of the image is H pixels, then you should set the -SLICES_PER_FRAME to some number which divides H/16. For example, if -the image is 240 pixels (15 macroblocks) high, then you should use -only 15, 5, 3, or 1 slices per frame. - -<p>Note: these MPEG playback systems are really wrong, since the MPEG -standard says this doesn't have to be so. - - - -<h3>Search Window</h3> - -<p>The search window is the window in which <b>ppmtompeg</b> searches -for motion vectors. The window is a square. You can specify the size -of the square, and whether to allow half-pixel motion vectors or not, -with the <b>RANGE</b> and <b>PIXEL</B> parameter file statements. - -<h3 id="ipb">I Frames, P Frames, B Frames</h3> - -<p>In MPEG-1, a movie is represented as a sequence of MPEG frames, -each of which is an I Frame, a P Frame, or a B Frame. Each represents -an actual frame of the movie (don't get confused by the dual use of -the word "frame." A movie frame is a graphical image. An MPEG frame -is a set of data that describes a movie frame). - -<p>An I frame ("intra" frame) describes a movie frame in isolation -- -without respect to any other frame in the movie. A P frame -("predictive" frame) describes a movie frame by describing how it -differs from the movie frame described by the latest preceding I or -P frame. A B frame ("bidirectional" frame) describes a movie frame by -describing how it differs from the movie frames described by the -nearest I or P frame before <em>and</em> after it. - -<p>Note that the first frame of a movie must be described by an I -frame (because there is no previous movie frame) and the last movie -frame must be described by an I or P frame (because there is no -subsequent movie frame). - -<p>Beyond that, you can choose which frames are represented by which -types. You specify a pattern, such as IBPBP and <b>ppmtompeg</b> -simply repeats it over and over throughout the movie. The pattern -affects speed, quality, and stream size. Here is a chart which shows -some of the trade-offs: - -<table border="1" cellpadding="5" cellspacing="0" -summary="Comparison of I/P/B Frames"> - <caption>Comparison of I/P/B Frames (Normalized)</caption> -<?makeman r c c c. ?> -<?makeman _ ?> - <tr align="center"> - <th>Frame Type</th> - <th>Size</th> - <th>Speed</th> - <th>Quality</th> - </tr> - <tr> - <td align="right">I frames</td> - <td align="center">1000</td> - <td align="center">1000</td> - <td align="center">1000</td> - </tr> - <tr> - <td align="right">P frames</td> - <td align="center">409</td> - <td align="center">609</td> - <td align="center">969</td> - </tr> - <tr> - <td align="right">B frames</td> - <td align="center">72</td> - <td align="center">260</td> - <td align="center">919</td> - </tr> - </table> - -(this is with constant qscale) - -<p>A standard sequence is IBBPBBPBBPBBPBB. - -<p>Select the sequence with the <B>PATTERN</B> parameter file statement. - -<p>Since the last MPEG frame cannot be a B frame (see above), if the -pattern you specify indicates a B frame for the last movie frame of -the movie, <b>ppmtompeg</b> makes it an I frame instead. - -<p>Before Netpbm 10.26 (January 2005), <b>ppmtompeg</b> instead drops -the trailing B frames by default, and you need the -<b>FORCE_ENCODE_LAST_FRAME</b> parameter file statement to make it do -this. - -<p>The MPEG frames don't appear in the MPEG-1 stream in the same order that -the corresponding movie frames appear in the movie -- the B frames come after -the I and P frames on which they are based. For example, if the movie is -4 frames that you will represent with the pattern IBBP, the MPEG-1 stream -will start with an I frame describing movie frame 0. The next frame in -the MPEG-1 stream is a P frame describing movie frame 3. The last two -frames in the MPEG-1 stream are B frames describing movie frames 1 and 2, -respectively. - - -<h3>Specifying Input and Output Files</h3> - -<p>Specify the input frame images with the <B>INPUT_DIR</B>, -<B>INPUT</B>, <B>END_INPUT</B>, <B>BASE_FILE_FORMAT</B>, -<B>SIZE</B>, <B>YUV_FORMAT</B> and <b>INPUT_CONVERT</B> parameter -file statements. - -<p>Specify the output file with the <b>OUTPUT</b> parameter file statement. - - -<h3>Statistics</h3> - -<p><b>ppmtompeg</b> can generate a variety of statistics about the -encoding. See the <b>-stat</b>, <b>-snr</b>, <b>-mv_histogram</b>, -<b>-quiet</b>, <b>-no_frame_summary</b>, and <b>-bit_rate_info</b> -options. - - -<H2 id="parallel">PARALLEL OPERATION</H2> - -<P>You can run <b>ppmtompeg</b> on multiple machines at once, encoding -the same MPEG stream. When you do, the machines are used as shown in -the following diagram. We call this "parallel mode." - -<p><img src="ppmtompeg-par.gif" alt="ppmtompeg-par.gif"> - -<p>To do parallel processing, put the statement - -<pre> - PARALLEL -</pre> - -in the parameter file, followed by a listing of the machines, one -machine per line, then - -<pre> - END_PARALLEL -</pre> - -Each of the machine lines must be in one of two forms. If the machine -has filesystem access to the input files, then the line is: - -<p> -<i>machine</i> <i>user</i> <i>executable</i> - -<P>The executable is normally <b>ppmtompeg</b> (you may need to give -the complete path if you've built for different architectures). If -the machine does not have filesystem access to the input files, the line -is: - -<P><b>REMOTE</b> <i>machine</i> <i>user</i> <i>executable</i> -<i>parameter file</i> - -<p>The <b>-max_machines</b> command option limits the number of -machines <b>ppmtompeg</b> will use. If you specify more machines in -the parameter file than <b>-max_machines</b> allows, <b>ppmtompeg</b> -uses only the machines listed first. This is handy if you want to -experiment with different amounts of parallelism. - -<p>In general, you should use full path file names when describing -executables and parameter files. This <em>includes</em> the parameter -file argument on the original invocation of <b>ppmtompeg</b>. - -<p>All file names must be the same on all systems (so if e.g. you're -using an NFS filesystem, you must make sure it is mounted at the same -mountpoint on all systems). - -<P>Because not all of the processes involved in parallel operation -have easy access to the input files, you must specify the <B>SIZE</B> -parameter file statement when you do parallel operation. - -<p>The machine on which you originally invoke <b>ppmtompeg</b> is the -master machine. It hosts a "combine server,", a -"decode server," and a number of "i/o servers," -all as separate processes. The other machines in the network (listed -in the parameter file) are slave machines. Each hosts a single -process that continuously requests work from the master and does it. -The slave process does the computation to encode MPEG frames. It -processes frames in batches identified by the master. - -<p>The master uses a remote shell command to start a process on a -slave machine. By default, it uses an <b>rsh</b> shell command to do -this. But use the <b>RSH</b> parameter file statement to control -this. The shell command the master executes remotely is -<b>ppmtompeg</b>, but with options to indicate that it is to perform -slave functions. - -<p>The various machines talk to each other over TCP connections. Each -machine finds and binds to a free TCP port number and tells its -partners the port number. These port numbers are at least 2048. - -<p>Use the PARALLEL_TEST_FRAMES, PARALLEL_TIME_CHUNKS, and -PARALLEL_PERFECT parameter file statements to control the way the -master divides up work among the slaves. - -<p>Use the <b>-nice</b> command option to cause all slave processes to run -"nicely," i.e. as low priority processes. That way, this substantial and -long-running CPU load will have minimal impact on other, possibly -interactive, users of the systems. - -<A NAME="speed"> </A> -<H2>SPEED</h2> - -<p>Here is a look at <b>ppmtompeg</b> speed, in single-node (not parallel) -operation: - -<table border="1" cellpadding="5" cellspacing="0" summary="Compression speed"> - <caption>Compression Speed</caption> -<?makeman r c. ?> -<?makeman _ ?> - <tr align="center"> - <th>Machine Type</th> - <th>Macroblocks per second<sup>1</sup></th> - </tr> - <tr> - <td align="right">HP 9000/755</td> - <td align="center">280</td> - </tr> - <tr> - <td align="right">DEC 3000/400</td> - <td align="center">247</td> - </tr> - <tr> - <td align="right">HP 9000/750</td> - <td align="center">191</td> - </tr> - <tr> - <td align="right">Sparc 10</td> - <td align="center">104</td> - </tr> - <tr> - <td align="right">DEC 5000</td> - <td align="center">68</td> - </tr> -</table> -<sup>1</sup>A macroblock is a 16x16 pixel square - -<p>The measurements in the table are with inputs and outputs via a -conventional locally attached filesystem. If you are using a network -filesystem over a single 10 MB/s Ethernet, that constrains your speed more -than your CPU speed. In that case, don't expect to get better than 4 -or 5 frames per second no matter how fast your CPUs are. - -<p>Network speed is even more of a bottleneck when the slaves do not -have filesystem access to the input files -- i.e. you declare them -REMOTE. - -<p>Where I/O is the bottleneck, size of the input frames can make a big -difference. So YUV input is better than PPM, and JPEG is better than -both. - -<p>When you're first trying to get parallel mode working, be sure to -use the <b>-debug_machines</b> option so you can see what's going on. -Also, <b>-debug_sockets</b> can help you diagnose communication -problems. - - -<H2 id="authors">AUTHORS</H2> - -<UL> - -<LI>Kevin Gong - University of California, Berkeley, <A -HREF="mailto:keving@cs.berkeley.edu">keving@cs.berkeley.edu</A> - -<LI>Ketan Patel - University of California, Berkeley, <A -HREF="mailto:kpatel@cs.berkeley.edu">kpatel@cs.berkeley.edu</A> - -<LI>Dan Wallach - University of California, Berkeley, <A -HREF="mailto:dwallach@cs.berkeley.edu">dwallach@cs.berkeley.edu</A> - -<LI>Darryl Brown - University of California, Berkeley, <A -HREF="mailto:darryl@cs.berkeley.edu">darryl@cs.berkeley.edu</A> - -<LI>Eugene Hung - University of California, Berkeley, <A -HREF="mailto:eyhung@cs.berkeley.edu">eyhung@cs.berkeley.edu</A> - -<LI>Steve Smoot - University of California, Berkeley, <A -HREF="mailto:smoot@cs.berkeley.edu">smoot@cs.berkeley.edu</A> - -</UL> - -<HR> -<A NAME="index"> </A> -<H2>Table Of Contents</H2> -<UL> -<LI><A HREF="#synopsis">SYNOPSIS</A></LI> -<LI><A HREF="#description">DESCRIPTION</A></LI> -<LI><A HREF="#options">OPTIONS</A></LI> -<LI><A HREF="#parmfile">PARAMETER FILE</A></LI> -<LI><A HREF="#general">GENERAL USAGE INFORMATION</A></LI> -<LI><A HREF="#parallel">PARALLEL OPERATION</A></LI> -<LI><A HREF="#speed">SPEED</A></LI> -<LI><A HREF="#authors">AUTHORS</A></LI> -</UL> -</BODY> -</HTML>