Fix crash when decoding 1920x1080 jpeg to YUV420
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Hans de Goede
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commit
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@ -0,0 +1,91 @@
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From 757d7910ddf43d9a9187dddae4f51a57fb723e8d Mon Sep 17 00:00:00 2001
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From: Hans de Goede <hdegoede@redhat.com>
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Date: Thu, 20 Nov 2014 13:03:35 +0100
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Subject: [PATCH] v4lconvert: Fix decoding of jpeg data with no vertical
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sub-sampling
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Our YUV output is always 2x subsampled in both vertical and horizontal
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direction, but some cameras generate JPEG data which is only subsampled in
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the horizontal direction.
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Since averaging the extra UV data these JPEGs contains is seomwhat slow,
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and UV data is not all that important anyways, we simple take every other
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line. Or at least that is the intent.
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But before this commit the code was not doing this properly, for each 16
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Y input lines 1 - 16 we also get 16 UV input lines 1 - 16, but we only need
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8 output lines. so we should store input line 1 or 2 in output line 1, input
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line 3 or 4 in output line 2, etc. Instead we were storing input lines
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9 - 16 into output lines 1 - 8, which leads to some unwanted color bleeding.
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More over this also leads for 1920x1080 JPEG to us writing (1080 / 8 + 1) / 2
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* 8 = 544 UV output lines rather then 540, this means that the last 4 U output
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lines overwrite the first 4 V output lines, and worse that the last 4 V output
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lines overrun the output buffer.
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So far this only lead to some wrong colors in various places, but since that
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we dynamically allocate the output buffer to just the right size this actually
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causes a crash.
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This commit fixes both the crash, and the wrong colors.
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Signed-off-by: Hans de Goede <hdegoede@redhat.com>
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---
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lib/libv4lconvert/jpeg.c | 37 ++++++++++++++++++++++++-------------
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1 file changed, 24 insertions(+), 13 deletions(-)
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diff --git a/lib/libv4lconvert/jpeg.c b/lib/libv4lconvert/jpeg.c
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index aa9cace..0142d44 100644
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--- a/lib/libv4lconvert/jpeg.c
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+++ b/lib/libv4lconvert/jpeg.c
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@@ -242,23 +242,34 @@ static int decode_libjpeg_h_samp2(struct v4lconvert_data *data,
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y_rows[y] = ydest;
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ydest += width;
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}
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- for (y = 0; y < 8; y++) {
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- u_rows[y] = udest;
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- v_rows[y] = vdest;
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- udest += width / 2;
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- vdest += width / 2;
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+ /*
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+ * For v_samp == 1 were going to get 1 set of uv values per
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+ * line, but we need only 1 set per 2 lines since our output
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+ * has v_samp == 2. We store every 2 sets in 1 line,
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+ * effectively using the second set for each output line.
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+ */
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+ if (v_samp == 1) {
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+ for (y = 0; y < 8; y++) {
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+ u_rows[y] = udest;
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+ v_rows[y] = vdest;
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+ y++;
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+ u_rows[y] = udest;
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+ v_rows[y] = vdest;
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+ udest += width / 2;
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+ vdest += width / 2;
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+ }
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+ } else { /* v_samp == 2 */
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+ for (y = 0; y < 8; y++) {
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+ u_rows[y] = udest;
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+ v_rows[y] = vdest;
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+ udest += width / 2;
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+ vdest += width / 2;
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+ }
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}
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+
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y = jpeg_read_raw_data(cinfo, rows, 8 * v_samp);
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if (y != 8 * v_samp)
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return -1;
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-
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- /* For v_samp == 1 were going to get another set of uv values,
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- but we need only 1 set since our output has v_samp == 2, so
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- rewind u and vdest and overwrite the previous set. */
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- if (cinfo->output_scanline % 16) {
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- udest -= width * 8 / 2;
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- vdest -= width * 8 / 2;
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- }
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}
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return 0;
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}
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--
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2.1.0
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@ -1,12 +1,13 @@
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Name: v4l-utils
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Version: 1.6.0
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Release: 1%{?dist}
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Release: 2%{?dist}
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Summary: Utilities for video4linux and DVB devices
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Group: Applications/System
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# libdvbv5, dvbv5 utils, ir-keytable and v4l2-sysfs-path are GPLv2 only
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License: GPLv2+ and GPLv2
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URL: http://www.linuxtv.org/downloads/v4l-utils/
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Source0: http://linuxtv.org/downloads/v4l-utils/v4l-utils-%{version}.tar.bz2
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Patch1: 0001-v4lconvert-Fix-decoding-of-jpeg-data-with-no-vertica.patch
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BuildRequires: libjpeg-devel qt4-devel kernel-headers desktop-file-utils
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BuildRequires: alsa-lib-devel doxygen
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# For /lib/udev/rules.d ownership
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@ -97,6 +98,7 @@ files for developing applications that use libdvbv5.
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%prep
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%setup -q
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%patch1 -p1
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%build
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@ -190,6 +192,9 @@ gtk-update-icon-cache %{_datadir}/icons/hicolor &>/dev/null || :
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%changelog
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* Thu Nov 20 2014 Hans de Goede <hdegoede@redhat.com> - 1.6.0-2
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- Fix crash when decoding 1920x1080 jpeg to YUV420
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* Sun Oct 05 2014 Mauro Carvalho Chehab - 1.6.0-1
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- Upgrade to version 1.6.0
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