[FFmpeg-trac] #1925(undetermined:new): Transcoding mjpeg video results in a very short frame
FFmpeg
trac at avcodec.org
Fri Nov 16 23:41:54 CET 2012
#1925: Transcoding mjpeg video results in a very short frame
-------------------------------------+-------------------------------------
Reporter: mbradshaw | Owner:
Type: defect | Status: new
Priority: normal | Component:
Version: git-master | undetermined
Keywords: | Resolution:
Blocking: | Blocked By:
Analyzed by developer: 0 | Reproduced by developer: 0
-------------------------------------+-------------------------------------
Description changed by mbradshaw:
Old description:
> '''Summary of the bug:'''
> I have a mjpeg video I've created using libav*. The video plays fine in
> QuickTime, VLC, ffplay, etc. However, when I transcode the mjpeg video
> using FFmpeg, the first frame goes from a duration of 1.315918 seconds to
> just a fraction of a second. This happens on every mjpeg file I've tested
> that I create using libav*.
>
> I've tried FFmpeg 1.0 and current git head; results are the same.
>
> I suppose it's possible I'm generating the mjpeg wrong, but it plays fine
> in everything I've tried (QuickTime, VLC, ffplay, etc.) with no warnings
> or errors, FFmpeg gives no errors or warnings when transcoding, and I've
> inspected the frames with ffprobe and I can't see anything wrong with the
> mjpeg.
>
> '''How to reproduce:'''
> Using the following command, the output file (mpg.mpg) has a short first
> frame and doesn't match the source mjpeg (mjpeg.mov). I have attached
> both files.
> {{{
> $ ffmpeg -i mjpeg.mov -vcodec mpeg2video -acodec mp2 -r 24 -bufsize
> 4000000 -maxrate 5000000 mpg.mpg
> ffmpeg version 1.0 Copyright (c) 2000-2012 the FFmpeg developers
> built on Nov 16 2012 15:00:58 with llvm-gcc 4.2.1 (LLVM build
> 2336.11.00)
> configuration:
> libavutil 51. 73.101 / 51. 73.101
> libavcodec 54. 59.100 / 54. 59.100
> libavformat 54. 29.104 / 54. 29.104
> libavdevice 54. 2.101 / 54. 2.101
> libavfilter 3. 17.100 / 3. 17.100
> libswscale 2. 1.101 / 2. 1.101
> libswresample 0. 15.100 / 0. 15.100
> [mov,mp4,m4a,3gp,3g2,mj2 @ 0x7fb25b00f200] max_analyze_duration 5000000
> reached at 5000272
> Input #0, mov,mp4,m4a,3gp,3g2,mj2, from 'mjpeg.mov':
> Metadata:
> major_brand : qt
> minor_version : 512
> compatible_brands: qt
> encoder : Lavf54.29.104
> Duration: 00:00:05.27, start: 0.000000, bitrate: 631 kb/s
> Stream #0:0(eng): Video: mjpeg (jpeg / 0x6765706A), yuvj420p,
> 1024x768, 536 kb/s, 1.02 fps, 4.58 tbr, 44100 tbn, 44100 tbc
> Metadata:
> handler_name : DataHandler
> Stream #0:1(eng): Audio: aac (mp4a / 0x6134706D), 44100 Hz, stereo,
> s16, 227 kb/s
> Metadata:
> handler_name : DataHandler
> Output #0, mpeg, to 'mpg.mpg':
> Metadata:
> major_brand : qt
> minor_version : 512
> compatible_brands: qt
> encoder : Lavf54.29.104
> Stream #0:0(eng): Video: mpeg2video, yuv420p, 1024x768, q=2-31, 200
> kb/s, 90k tbn, 24 tbc
> Metadata:
> handler_name : DataHandler
> Stream #0:1(eng): Audio: mp2, 44100 Hz, stereo, s16, 128 kb/s
> Metadata:
> handler_name : DataHandler
> Stream mapping:
> Stream #0:0 -> #0:0 (mjpeg -> mpeg2video)
> Stream #0:1 -> #0:1 (aac -> mp2)
> Press [q] to stop, [?] for help
> frame= 95 fps=0.0 q=31.0 Lsize= 766kB time=00:00:05.27
> bitrate=1189.9kbits/s dup=91 drop=0
> video:678kB audio:82kB subtitle:0 global headers:0kB muxing overhead
> 0.751412%
> }}}
>
> In the files, the symbol clash should match with the start of each frame.
New description:
'''Summary of the bug:'''
I have a mjpeg video I've created using libav*. The video plays fine in
QuickTime, VLC, ffplay, etc. However, when I transcode the mjpeg video
using FFmpeg, the first frame goes from a duration of 1.315918 seconds to
just a fraction of a second. This happens on every mjpeg file I've tested
that I create using libav*.
I've tried FFmpeg 1.0 and current git head; results are the same.
I suppose it's possible I'm generating the mjpeg wrong, but it plays fine
in everything I've tried (QuickTime, VLC, ffplay, etc.) with no warnings
or errors, FFmpeg gives no errors or warnings when transcoding, and I've
inspected the frames with ffprobe and I can't see anything wrong with the
mjpeg.
'''How to reproduce:'''
Using the following command, the output file (mpg.mpg) has a short first
frame and doesn't match the source mjpeg (mjpeg.mov). I have attached both
files. I should note that I get the same problem when using mpeg4/aac in
an mp4 container as output format.
{{{
$ ffmpeg -i mjpeg.mov -vcodec mpeg2video -acodec mp2 -r 24 -bufsize
4000000 -maxrate 5000000 mpg.mpg
ffmpeg version 1.0 Copyright (c) 2000-2012 the FFmpeg developers
built on Nov 16 2012 15:00:58 with llvm-gcc 4.2.1 (LLVM build
2336.11.00)
configuration:
libavutil 51. 73.101 / 51. 73.101
libavcodec 54. 59.100 / 54. 59.100
libavformat 54. 29.104 / 54. 29.104
libavdevice 54. 2.101 / 54. 2.101
libavfilter 3. 17.100 / 3. 17.100
libswscale 2. 1.101 / 2. 1.101
libswresample 0. 15.100 / 0. 15.100
[mov,mp4,m4a,3gp,3g2,mj2 @ 0x7fb25b00f200] max_analyze_duration 5000000
reached at 5000272
Input #0, mov,mp4,m4a,3gp,3g2,mj2, from 'mjpeg.mov':
Metadata:
major_brand : qt
minor_version : 512
compatible_brands: qt
encoder : Lavf54.29.104
Duration: 00:00:05.27, start: 0.000000, bitrate: 631 kb/s
Stream #0:0(eng): Video: mjpeg (jpeg / 0x6765706A), yuvj420p,
1024x768, 536 kb/s, 1.02 fps, 4.58 tbr, 44100 tbn, 44100 tbc
Metadata:
handler_name : DataHandler
Stream #0:1(eng): Audio: aac (mp4a / 0x6134706D), 44100 Hz, stereo,
s16, 227 kb/s
Metadata:
handler_name : DataHandler
Output #0, mpeg, to 'mpg.mpg':
Metadata:
major_brand : qt
minor_version : 512
compatible_brands: qt
encoder : Lavf54.29.104
Stream #0:0(eng): Video: mpeg2video, yuv420p, 1024x768, q=2-31, 200
kb/s, 90k tbn, 24 tbc
Metadata:
handler_name : DataHandler
Stream #0:1(eng): Audio: mp2, 44100 Hz, stereo, s16, 128 kb/s
Metadata:
handler_name : DataHandler
Stream mapping:
Stream #0:0 -> #0:0 (mjpeg -> mpeg2video)
Stream #0:1 -> #0:1 (aac -> mp2)
Press [q] to stop, [?] for help
frame= 95 fps=0.0 q=31.0 Lsize= 766kB time=00:00:05.27
bitrate=1189.9kbits/s dup=91 drop=0
video:678kB audio:82kB subtitle:0 global headers:0kB muxing overhead
0.751412%
}}}
In the files, the symbol clash should match with the start of each frame.
--
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Ticket URL: <https://ffmpeg.org/trac/ffmpeg/ticket/1925#comment:1>
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