Opened 12 years ago
Last modified 11 years ago
#2348 new defect
Slowmotion when reencoding mpeg stream
| Reported by: | Carl Eugen Hoyos | Owned by: | |
|---|---|---|---|
| Priority: | normal | Component: | undetermined |
| Version: | git-master | Keywords: | dts mpeg2video mpegps |
| Cc: | Blocked By: | ||
| Blocking: | Reproduced by developer: | no | |
| Analyzed by developer: | no |
Description
http://thread.gmane.org/gmane.comp.video.ffmpeg.user/44508
A user uploaded a mpeg sample file that plays for approximately 11 seconds with current ffplay, mplayer (both -demuxer mpegps and -demuxer lavf, both -vc ffmpeg12 and -vc mpeg12), vlc and WMP.
If the sample gets re-encoded with ffmpeg, the output file plays at half speed (for 22 seconds).
$ ffmpeg -i rob-test.mpg -qscale 2 out.avi
ffmpeg version N-50651-g1123080 Copyright (c) 2000-2013 the FFmpeg developers
built on Mar 11 2013 12:49:54 with gcc 4.7 (SUSE Linux)
configuration: --enable-gpl --disable-indev=jack --enable-libopenjpeg
libavutil 52. 19.100 / 52. 19.100
libavcodec 54. 92.100 / 54. 92.100
libavformat 54. 63.104 / 54. 63.104
libavdevice 54. 3.103 / 54. 3.103
libavfilter 3. 44.101 / 3. 44.101
libswscale 2. 2.100 / 2. 2.100
libswresample 0. 17.102 / 0. 17.102
libpostproc 52. 2.100 / 52. 2.100
[mpeg @ 0x1be0f40] max_analyze_duration 5000000 reached at 5005000 microseconds
Input #0, mpeg, from 'rob-test.mpg':
Duration: 00:00:11.34, start: 0.360000, bitrate: 7140 kb/s
Stream #0:0[0x1e0]: Video: mpeg2video (Main), yuv420p, 720x480 [SAR 32:27 DAR 16:9], 29.97 fps, 29.97 tbr, 90k tbn, 59.94 tbc
Please use -q:a or -q:v, -qscale is ambiguous
Output #0, avi, to 'out.avi':
Metadata:
ISFT : Lavf54.63.104
Stream #0:0: Video: mpeg4 (FMP4 / 0x34504D46), yuv420p, 720x480 [SAR 32:27 DAR 16:9], q=2-31, 200 kb/s, 29.97 tbn, 29.97 tbc
Stream mapping:
Stream #0:0 -> #0:0 (mpeg2video -> mpeg4)
Press [q] to stop, [?] for help
frame= 341 fps=0.0 q=2.0 Lsize= 11255kB time=00:00:22.68 bitrate=4063.5kbits/s
video:11233kB audio:0kB subtitle:0 global headers:0kB muxing overhead 0.193383%
Workaround is to specify an input frame rate:
$ ffmpeg -r 30 -i rob-test.mpg -qscale 2 out.avi
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The problem has changed, speed is correct but frames are dropped now:
$ ffmpeg -i rob-test.mpg -qscale 2 out.avi ffmpeg version N-59187-g09d6cea Copyright (c) 2000-2013 the FFmpeg developers built on Dec 18 2013 12:46:12 with gcc 4.7 (SUSE Linux) configuration: --enable-gpl --enable-libzvbi libavutil 52. 58.101 / 52. 58.101 libavcodec 55. 45.102 / 55. 45.102 libavformat 55. 22.100 / 55. 22.100 libavdevice 55. 5.102 / 55. 5.102 libavfilter 4. 0.100 / 4. 0.100 libswscale 2. 5.101 / 2. 5.101 libswresample 0. 17.104 / 0. 17.104 libpostproc 52. 3.100 / 52. 3.100 Input #0, mpeg, from 'rob-test.mpg': Duration: 00:00:11.34, start: 0.360000, bitrate: 7140 kb/s Stream #0:0[0x1e0]: Video: mpeg2video (Main), yuv420p(tv), 720x480 [SAR 32:27 DAR 16:9], max. 8500 kb/s, 29.97 fps, 29.97 tbr, 90k tbn, 59.94 tbc Please use -q:a or -q:v, -qscale is ambiguous Output #0, avi, to 'out.avi': Metadata: ISFT : Lavf55.22.100 Stream #0:0: Video: mpeg4 (FMP4 / 0x34504D46), yuv420p, 720x480 [SAR 32:27 DAR 16:9], q=2-31, 200 kb/s, 29.97 tbn, 29.97 tbc Stream mapping: Stream #0:0 -> #0:0 (mpeg2video -> mpeg4) Press [q] to stop, [?] for help frame= 228 fps=0.0 q=2.0 Lsize= 7526kB time=00:00:11.37 bitrate=5418.7kbits/s dup=0 drop=113 video:7512kB audio:0kB subtitle:0 global headers:0kB muxing overhead 0.182652%