mirror of
https://gitlab.freedesktop.org/gstreamer/gstreamer.git
synced 2024-12-20 23:36:38 +00:00
e6d83d8f96
The libjpeg-turbo has a built-in support for performing colorspace
conversion. The performance of this conversion is much better than
doing the same separately using videoconvert. Implement support for
this conversion to RGBx/xRGB/BGRx/xBGR formats. Other formats can
be easily added later.
- The decoding of various pixel formats can be tested and compared to
non-libjpeg-turbo decoding as follows:
for gfmt in {RGB,BGR}{,x} x{RGB,BGR} ; do
echo "$gfmt"
gst-launch-1.0 -q \
videotestsrc pattern=colors ! \
video/x-raw,format=${gfmt} ! \
fakesink dump=true | \
head -n 200 | tail -n 1
gst-launch-1.0 -q --gst-plugin-path=build/ext/jpeg/ \
videotestsrc pattern=colors ! \
video/x-raw,format=${gfmt} ! \
jpegenc ! \
jpegdec ! \
video/x-raw,format=${gfmt} ! \
fakesink dump=true | \
head -n 200 | tail -n 1
done
Result looks as follows, i.e. comparable:
RGB
00000c70 (0x7f7736fbdd10): 05 33 19 05 33 26 05 33 33 05 33 40 05 33 4c 05 .3..3&.33.3@.3L.
00000c70 (0x7f389e8f7d10): 05 32 17 04 32 22 04 32 31 04 32 3e 04 32 4a 04 .2..2".21.2>.2J.
RGBx
00000c70 (0x7f79efd0ad10): cc 07 22 ff d9 07 22 ff e6 07 22 ff f3 07 22 ff .."..."..."...".
00000c70 (0x7fb6989f3d10): cd 06 22 00 d9 06 22 00 e6 06 22 00 f4 06 22 00 .."..."..."...".
BGR
00000c70 (0x7fa0a6c42d10): 05 0c 33 05 19 33 05 26 33 05 33 33 05 40 33 05 ..3..3.&3.33.@3.
00000c70 (0x7fc74165fd10): 05 08 32 04 17 32 04 22 32 04 31 32 04 3e 32 04 ..2..2."2.12.>2.
BGRx
00000c70 (0x7fbf399f1d10): 22 07 cc ff 22 07 d9 ff 22 07 e6 ff 22 07 f3 ff "..."..."..."...
00000c70 (0x7f50e3d1cd10): 22 06 cd 00 22 06 d9 00 22 06 e6 00 22 06 f4 00 "..."..."..."...
xRGB
00000c70 (0x7f0b950a2d10): ff cc 07 22 ff d9 07 22 ff e6 07 22 ff f3 07 22 ..."..."..."..."
00000c70 (0x7f4416b8dd10): 00 cd 06 22 00 d9 06 22 00 e6 06 22 00 f4 06 22 ..."..."..."..."
xBGR
00000c70 (0x7f237d74dd10): ff 22 07 cc ff 22 07 d9 ff 22 07 e6 ff 22 07 f3 ."..."..."..."..
00000c70 (0x7f095547dd10): 00 22 06 cd 00 22 06 d9 00 22 06 e6 00 22 06 f4 ."..."..."..."..
^^ ^^ ^^ ^^
Notice how the alpha channel is set to arbitrary value in case of the
libjpeg-turbo decoding into RGBx/BGRx/xRGB/xBGR pixel formats. This is
documented in libjpeg-turbo README.md as follows:
"
When using the RGBX, BGRX, XBGR, and XRGB colorspaces during decompression, the
X byte is undefined, and in order to ensure the best performance, libjpeg-turbo
can set that byte to whatever value it wishes.
"
- The interlaced num_fields=2 mjpeg stream can be generated and
tested as follows (this does require mjpegtools):
$ gst-launch-1.0 videotestsrc num-buffers=10 ! jpegenc ! multifilesink location=in%04d.jpg
$ jpeg2yuv -f 25 -I t -L 0 -j in%04d.jpg | yuv2lav -f avi -o result.avi
...
$ gst-launch-1.0 --gst-plugin-path=build/ext/jpeg/ filesrc location=result.avi ! \
avidemux ! jpegdec ! video/x-raw,format=RGBx ! videoconvert ! autovideosink
Signed-off-by: Marek Vasut <marex@denx.de>
Part-of: <https://gitlab.freedesktop.org/gstreamer/gstreamer/-/merge_requests/1091>
|
||
|---|---|---|
| .. | ||
| gstjpeg.c | ||
| gstjpeg.h | ||
| gstjpegdec.c | ||
| gstjpegdec.h | ||
| gstjpegelements.h | ||
| gstjpegenc.c | ||
| gstjpegenc.h | ||
| gstjpegplugin.c | ||
| gstsmokedec.c | ||
| gstsmokedec.h | ||
| gstsmokeenc.c | ||
| gstsmokeenc.h | ||
| meson.build | ||
| README | ||
| smokecodec.c | ||
| smokecodec.h | ||
| smokeformat.h | ||
The Smoke Codec --------------- This is a very simple compression algorithm I was toying with when doing a Java based player. Decoding a JPEG in Java has acceptable speed so this codec tries to exploit that feature. The algorithm first compares the last and the new image and finds all 16x16 blocks that have a squared difference bigger than a configurable threshold. Then all these blocks are compressed into an NxM JPEG. The quality of the JPEG is inversely proportional to the number of blocks, this way, the picture quality degrades with heavy motion scenes but the bitrate stays more or less constant. Decoding decompresses the JPEG and then updates the old picture with the new blocks. TODO: ---- - make format extensible - motion vectors - do some real bitrate control