Opened 11 years ago
Closed 4 years ago
#2333 closed defect (needs_more_info)
mkv + ac3 remux adds a little time
| Reported by: | Squeeto | Owned by: | |
|---|---|---|---|
| Priority: | normal | Component: | undetermined |
| Version: | unspecified | Keywords: | |
| Cc: | Blocked By: | ||
| Blocking: | Reproduced by developer: | no | |
| Analyzed by developer: | no |
Description
ffmpeg adds time to the muxed mkv and demuxed mkv:
ffmpeg version N-50025-gb8bb661 Copyright (c) 2000-2013 the FFmpeg developers
built on Feb 17 2013 02:37:45 with gcc 4.7.2 (GCC)
configuration: --enable-gpl --enable-version3 --disable-w32threads --enable-avisynth --enable-bzlib --enable-fontconfig --enable-frei0r --enable-gnutls --enable-libass --enable-libbluray --enable-libcaca --enable-libfreetype --enable-libgsm --enable-libmp3lame --enable-libopencore-amrnb --enable-libopencore-amrwb --enable-libopenjpeg --enable-libopus --enable-librtmp --enable-libschroedinger --enable-libsoxr --enable-libspeex --enable-libtheora --enable-libtwolame --enable-libvo-aacenc --enable-libvo-amrwbenc --enable-libvorbis --enable-libvpx --enable-libx264 --enable-libxavs --enable-libxvid --enable-zlib
libavutil 52. 17.101 / 52. 17.101
libavcodec 54. 91.103 / 54. 91.103
libavformat 54. 63.100 / 54. 63.100
libavdevice 54. 3.103 / 54. 3.103
libavfilter 3. 38.100 / 3. 38.100
libswscale 2. 2.100 / 2. 2.100
libswresample 0. 17.102 / 0. 17.102
libpostproc 52. 2.100 / 52. 2.100
ffmpeg -i input.mkv -i input.ac3 -map 0:0 -map 1:0 -vcodec copy -acodec copy -y done.mkv
Input #0, matroska,webm, from 'input.mkv':
Duration: 00:00:12.85, start: 0.000000, bitrate: 6039 kb/s
Input #0, ac3, from 'input.ac3':
Duration: 00:00:12.86, start: 0.000000, bitrate: 256 kb/s
Input #0, matroska,webm, from 'done.mkv':
Metadata:
ENCODER : Lavf54.63.100
Duration: 00:00:12.93, start: 0.000000, bitrate: 6256 kb/s
ffmpeg -i done.mkv -an -vcodec copy -y demux.mkv
ffmpeg -i done.mkv -acodec copy -vn -y demux.ac3
Input #0, matroska,webm, from 'demux.mkv':
Metadata:
ENCODER : Lavf54.63.100
Duration: 00:00:12.91, start: 0.000000, bitrate: 6008 kb/s
Input #0, ac3, from 'demux.ac3':
Duration: 00:00:12.86, start: 0.000000, bitrate: 256 kb/s
Change History (8)
follow-ups: 2 5 comment:1 by , 11 years ago
comment:2 by , 11 years ago
Replying to cehoyos:
To make this a valid ticket, please provide your failing command line including complete, unedited console output and please consider using a "Code block".
Please note the Duration discrepancies:
ffmpeg -i input.mkv -i input.ac3 -map 0:0 -map 1:0 -vcodec copy -acodec copy -y done.mkv
ffmpeg version N-50025-gb8bb661 Copyright (c) 2000-2013 the FFmpeg developers
built on Feb 17 2013 02:37:45 with gcc 4.7.2 (GCC)
configuration: --enable-gpl --enable-version3 --disable-w32threads --enable-avisynth --enable-bzlib --enable-fontconfig --enable-frei0r --enable-gnutls --enable-libass --enable-libbluray --enable-libcaca --enable-libfreetype --enable-libgsm --enable-libmp3lame --enable-libopencore-amrnb --enable-libopencore-amrwb --enable-libopenjpeg --enable-libopus --enable-librtmp --enable-libschroedinger --enable-libsoxr --enable-libspeex --enable-libtheora --enable-libtwolame --enable-libvo-aacenc --enable-libvo-amrwbenc --enable-libvorbis --enable-libvpx --enable-libx264 --enable-libxavs --enable-libxvid --enable-zlib
libavutil 52. 17.101 / 52. 17.101
libavcodec 54. 91.103 / 54. 91.103
libavformat 54. 63.100 / 54. 63.100
libavdevice 54. 3.103 / 54. 3.103
libavfilter 3. 38.100 / 3. 38.100
libswscale 2. 2.100 / 2. 2.100
libswresample 0. 17.102 / 0. 17.102
libpostproc 52. 2.100 / 52. 2.100
Input #0, matroska,webm, from 'input.mkv':
Duration: 00:00:12.85, start: 0.000000, bitrate: 6039 kb/s
Stream #0:0(eng): Video: h264 (High), yuv420p, 1920x1080, SAR 1:1 DAR 16:9, 29.97 fps, 29.97 tbr, 20k tbn, 59.94 tbc (default)
[ac3 @ 025ad320] max_analyze_duration 5000000 reached at 5024000 microseconds
[ac3 @ 025ad320] Estimating duration from bitrate, this may be inaccurate
Input #1, ac3, from 'input.ac3':
Duration: 00:00:12.86, start: 0.000000, bitrate: 256 kb/s
Stream #1:0: Audio: ac3, 48000 Hz, stereo, fltp, 256 kb/s
Output #0, matroska, to 'done.mkv':
Metadata:
encoder : Lavf54.63.100
Stream #0:0(eng): Video: h264 (H264 / 0x34363248), yuv420p, 1920x1080 [SAR 1:1 DAR 16:9], q=2-31, 29.97 fps, 1k tbn, 20k tbc (default)
Stream #0:1: Audio: ac3 ([0] [0][0] / 0x2000), 48000 Hz, stereo, 256 kb/s
Stream mapping:
Stream #0:0 -> #0:0 (copy)
Stream #1:0 -> #0:1 (copy)
Press [q] to stop, [?] for help
frame= 385 fps=0.0 q=-1.0 Lsize= 9876kB time=00:00:12.86 bitrate=6289.3kbits/s
video:9468kB audio:402kB subtitle:0 global headers:0kB muxing overhead 0.065323%
ffmpeg -i done.mkv -an -vcodec copy -y demux.mkv
ffmpeg version N-50025-gb8bb661 Copyright (c) 2000-2013 the FFmpeg developers
built on Feb 17 2013 02:37:45 with gcc 4.7.2 (GCC)
configuration: --enable-gpl --enable-version3 --disable-w32threads --enable-avisynth --enable-bzlib --enable-fontconfig --enable-frei0r --enable-gnutls --enable-libass --enable-libbluray --enable-libcaca --enable-libfreetype --enable-libgsm --enable-libmp3lame --enable-libopencore-amrnb --enable-libopencore-amrwb --enable-libopenjpeg --enable-libopus --enable-librtmp --enable-libschroedinger --enable-libsoxr --enable-libspeex --enable-libtheora --enable-libtwolame --enable-libvo-aacenc --enable-libvo-amrwbenc --enable-libvorbis --enable-libvpx --enable-libx264 --enable-libxavs --enable-libxvid --enable-zlib
libavutil 52. 17.101 / 52. 17.101
libavcodec 54. 91.103 / 54. 91.103
libavformat 54. 63.100 / 54. 63.100
libavdevice 54. 3.103 / 54. 3.103
libavfilter 3. 38.100 / 3. 38.100
libswscale 2. 2.100 / 2. 2.100
libswresample 0. 17.102 / 0. 17.102
libpostproc 52. 2.100 / 52. 2.100
Input #0, matroska,webm, from 'done.mkv':
Metadata:
ENCODER : Lavf54.63.100
Duration: 00:00:12.93, start: 0.000000, bitrate: 6256 kb/s
Stream #0:0(eng): Video: h264 (High), yuv420p, 1920x1080, SAR 1:1 DAR 16:9, 29.97 fps, 29.97 tbr, 1k tbn, 59.94 tbc (default)
Stream #0:1: Audio: ac3, 48000 Hz, stereo, fltp, 256 kb/s
Output #0, matroska, to 'demux.mkv':
Metadata:
encoder : Lavf54.63.100
Stream #0:0(eng): Video: h264 (H264 / 0x34363248), yuv420p, 1920x1080 [SAR 1:1 DAR 16:9], q=2-31, 29.97 fps, 1k tbn, 1k tbc (default)
Stream mapping:
Stream #0:0 -> #0:0 (copy)
Press [q] to stop, [?] for help
frame= 385 fps=0.0 q=-1.0 Lsize= 9471kB time=00:00:12.81 bitrate=6055.1kbits/s
video:9468kB audio:0kB subtitle:0 global headers:0kB muxing overhead 0.038442%
ffmpeg -i done.mkv -acodec copy -vn -y demux.ac3
ffmpeg version N-50025-gb8bb661 Copyright (c) 2000-2013 the FFmpeg developers
built on Feb 17 2013 02:37:45 with gcc 4.7.2 (GCC)
configuration: --enable-gpl --enable-version3 --disable-w32threads --enable-avisynth --enable-bzlib --enable-fontconfig --enable-frei0r --enable-gnutls --enable-libass --enable-libbluray --enable-libcaca --enable-libfreetype --enable-libgsm --enable-libmp3lame --enable-libopencore-amrnb --enable-libopencore-amrwb --enable-libopenjpeg --enable-libopus --enable-librtmp --enable-libschroedinger --enable-libsoxr --enable-libspeex --enable-libtheora --enable-libtwolame --enable-libvo-aacenc --enable-libvo-amrwbenc --enable-libvorbis --enable-libvpx --enable-libx264 --enable-libxavs --enable-libxvid --enable-zlib
libavutil 52. 17.101 / 52. 17.101
libavcodec 54. 91.103 / 54. 91.103
libavformat 54. 63.100 / 54. 63.100
libavdevice 54. 3.103 / 54. 3.103
libavfilter 3. 38.100 / 3. 38.100
libswscale 2. 2.100 / 2. 2.100
libswresample 0. 17.102 / 0. 17.102
libpostproc 52. 2.100 / 52. 2.100
Input #0, matroska,webm, from 'done.mkv':
Metadata:
ENCODER : Lavf54.63.100
Duration: 00:00:12.93, start: 0.000000, bitrate: 6256 kb/s
Stream #0:0(eng): Video: h264 (High), yuv420p, 1920x1080, SAR 1:1 DAR 16:9, 29.97 fps, 29.97 tbr, 1k tbn, 59.94 tbc (default)
Stream #0:1: Audio: ac3, 48000 Hz, stereo, fltp, 256 kb/s
Output #0, ac3, to 'demux.ac3':
Metadata:
encoder : Lavf54.63.100
Stream #0:0: Audio: ac3, 48000 Hz, stereo, 256 kb/s
Stream mapping:
Stream #0:1 -> #0:0 (copy)
Press [q] to stop, [?] for help
size= 402kB time=00:00:12.93 bitrate= 254.7kbits/s
video:0kB audio:402kB subtitle:0 global headers:0kB muxing overhead 0.000000%
ffmpeg -i demux.mkv
ffmpeg version N-50025-gb8bb661 Copyright (c) 2000-2013 the FFmpeg developers
built on Feb 17 2013 02:37:45 with gcc 4.7.2 (GCC)
configuration: --enable-gpl --enable-version3 --disable-w32threads --enable-avisynth --enable-bzlib --enable-fontconfig --enable-frei0r --enable-gnutls --enable-libass --enable-libbluray --enable-libcaca --enable-libfreetype --enable-libgsm --enable-libmp3lame --enable-libopencore-amrnb --enable-libopencore-amrwb --enable-libopenjpeg --enable-libopus --enable-librtmp --enable-libschroedinger --enable-libsoxr --enable-libspeex --enable-libtheora --enable-libtwolame --enable-libvo-aacenc --enable-libvo-amrwbenc --enable-libvorbis --enable-libvpx --enable-libx264 --enable-libxavs --enable-libxvid --enable-zlib
libavutil 52. 17.101 / 52. 17.101
libavcodec 54. 91.103 / 54. 91.103
libavformat 54. 63.100 / 54. 63.100
libavdevice 54. 3.103 / 54. 3.103
libavfilter 3. 38.100 / 3. 38.100
libswscale 2. 2.100 / 2. 2.100
libswresample 0. 17.102 / 0. 17.102
libpostproc 52. 2.100 / 52. 2.100
Input #0, matroska,webm, from 'demux.mkv':
Metadata:
ENCODER : Lavf54.63.100
Duration: 00:00:12.91, start: 0.000000, bitrate: 6008 kb/s
Stream #0:0(eng): Video: h264 (High), yuv420p, 1920x1080, SAR 1:1 DAR 16:9, 29.97 fps, 29.97 tbr, 1k tbn, 59.94 tbc (default)
At least one output file must be specified
ffmpeg -i demux.ac3
ffmpeg version N-50025-gb8bb661 Copyright (c) 2000-2013 the FFmpeg developers
built on Feb 17 2013 02:37:45 with gcc 4.7.2 (GCC)
configuration: --enable-gpl --enable-version3 --disable-w32threads --enable-avisynth --enable-bzlib --enable-fontconfig --enable-frei0r --enable-gnutls --enable-libass --enable-libbluray --enable-libcaca --enable-libfreetype --enable-libgsm --enable-libmp3lame --enable-libopencore-amrnb --enable-libopencore-amrwb --enable-libopenjpeg --enable-libopus --enable-librtmp --enable-libschroedinger --enable-libsoxr --enable-libspeex --enable-libtheora --enable-libtwolame --enable-libvo-aacenc --enable-libvo-amrwbenc --enable-libvorbis --enable-libvpx --enable-libx264 --enable-libxavs --enable-libxvid --enable-zlib
libavutil 52. 17.101 / 52. 17.101
libavcodec 54. 91.103 / 54. 91.103
libavformat 54. 63.100 / 54. 63.100
libavdevice 54. 3.103 / 54. 3.103
libavfilter 3. 38.100 / 3. 38.100
libswscale 2. 2.100 / 2. 2.100
libswresample 0. 17.102 / 0. 17.102
libpostproc 52. 2.100 / 52. 2.100
[ac3 @ 0226b420] max_analyze_duration 5000000 reached at 5024000 microseconds
[ac3 @ 0226b420] Estimating duration from bitrate, this may be inaccurate
Input #0, ac3, from 'demux.ac3':
Duration: 00:00:12.86, start: 0.000000, bitrate: 256 kb/s
Stream #0:0: Audio: ac3, 48000 Hz, stereo, fltp, 256 kb/s
At least one output file must be specified
comment:3 by , 11 years ago
Has my question been properly requested?
It has been a week so I am not sure if you are still waiting.
Recap:
input.mkv 12.85 sec input.ac3 12.86 done.mkv (ffmpeg copy) 12.93 demux.mkv 12.91 demux.ac3 12.86
comment:4 by , 11 years ago
If I understand correctly, you fear that remuxing makes your audio files longer. The only way to prove this is to decode both the original file and the remuxed file to wav files and compare them.
Or do I misunderstand the issue?
comment:5 by , 11 years ago
I started this question at http://ffmpeg.zeranoe.com/forum; it was there that the demuxed times were asked for trouble-shooting purposes.
I only want to mux the input.mkv and input.ac3. I would prefer to use ffmpeg but I noticed that mkvmerge makes a done.mkv of 12.86 seconds. Why does ffmpeg add a little time? Does it matter? Can I still splice together done.mkv, done2.mkv, done3.mkv, etc. and expect doneTotal.mkv to be okay?
I am not concerned that input.ac3 is a little longer than input.mkv.
Thank you
comment:6 by , 11 years ago
Hi again.
I found this branch of ffmpeg called ffmbc that creates an output mkv file of 12.86 seconds as I am hoping for.
ffmpeg -i done_ffmbc.mkv
ffmpeg version N-50025-gb8bb661 Copyright (c) 2000-2013 the FFmpeg developers
built on Feb 17 2013 02:37:45 with gcc 4.7.2 (GCC)
configuration: --enable-gpl --enable-version3 --disable-w32threads --enable-avisynth --enable-bzlib --enable-fontconfig --enable-frei0r --enable-gnutls --enable-libass --enable-libbluray --enable-libcaca --enable-libfreetype --enable-libgsm --enable-libmp3lame --enable-libopencore-amrnb --enable-libopencore-amrwb --enable-libopenjpeg --enable-libopus --enable-librtmp --enable-libschroedinger --enable-libsoxr --enable-libspeex --enable-libtheora --enable-libtwolame --enable-libvo-aacenc --enable-libvo-amrwbenc --enable-libvorbis --enable-libvpx --enable-libx264 --enable-libxavs --enable-libxvid --enable-zlib
libavutil 52. 17.101 / 52. 17.101
libavcodec 54. 91.103 / 54. 91.103
libavformat 54. 63.100 / 54. 63.100
libavdevice 54. 3.103 / 54. 3.103
libavfilter 3. 38.100 / 3. 38.100
libswscale 2. 2.100 / 2. 2.100
libswresample 0. 17.102 / 0. 17.102
libpostproc 52. 2.100 / 52. 2.100
Input #0, matroska,webm, from 'done_ffmbc.mkv':
Metadata:
ENCODER : FFmbc 0.7
Duration: 00:00:12.86, start: 0.000000, bitrate: 6289 kb/s
Stream #0:0: Video: h264 (High), yuv420p, 1920x1080, SAR 1:1 DAR 16:9, 20k fps, 20k tbr, 1k tbn, 59.94 tbc (default)
Stream #0:1: Audio: ac3, 48000 Hz, stereo, fltp, 256 kb/s (default)
At least one output file must be specified
comment:7 by , 11 years ago
maybe it's rounding up or something, when reporting time back to the container?
comment:8 by , 4 years ago
| Resolution: | → needs_more_info |
|---|---|
| Status: | new → closed |
I am closing this as needs_more_info, because there have been no samples provided. Nevertheless, based upon the information from your post at zeranoe's forum I can already guess what happened here. But for the record, here is the post I am basing my answer on:
Here is the first and last packets from: original mkv = zoutput.mkv original ac3 = zoutput_f.ac3 mux = done2 and demuxed = zvideo.mkv and zaudio.ac3 [zoutput.mkv] [PACKET] codec_type=video stream_index=0 pts=0 pts_time=0.000000 dts=N/A dts_time=N/A duration=N/A duration_time=N/A convergence_duration=N/A convergence_duration_time=N/A size=238017 pos=241 flags=K [/PACKET] [PACKET] codec_type=video stream_index=0 pts=255588 pts_time=12.779400 dts=254921 dts_time=12.746050 duration=667 duration_time=0.033350 convergence_duration=N/A convergence_duration_time=N/A size=27305 pos=27899741 flags=_ [/PACKET] [zoutput_f.ac3] [PACKET] codec_type=audio stream_index=0 pts=0 pts_time=0.000000 dts=0 dts_time=0.000000 duration=2880 duration_time=0.032000 convergence_duration=N/A convergence_duration_time=N/A size=1024 pos=0 flags=K [/PACKET] [PACKET] codec_type=audio stream_index=0 pts=1154880 pts_time=12.832000 dts=1154880 dts_time=12.832000 duration=2880 duration_time=0.032000 convergence_duration=N/A convergence_duration_time=N/A size=1024 pos=410624 flags=K [/PACKET] [done2] [PACKET] codec_type=video stream_index=0 pts=67 pts_time=0.067000 dts=N/A dts_time=N/A duration=N/A duration_time=N/A convergence_duration=N/A convergence_duration_time=N/A size=238017 pos=705 flags=K [/PACKET] [PACKET] codec_type=audio stream_index=1 pts=12899 pts_time=12.899000 dts=12899 dts_time=12.899000 duration=32 duration_time=0.032000 convergence_duration=N/A convergence_duration_time=N/A size=1024 pos=28340735 flags=K [/PACKET] [zvideo.mkv] [PACKET] codec_type=video stream_index=0 pts=67 pts_time=0.067000 dts=N/A dts_time=N/A duration=N/A duration_time=N/A convergence_duration=N/A convergence_duration_time=N/A size=238017 pos=644 flags=K [/PACKET] [PACKET] codec_type=video stream_index=0 pts=12846 pts_time=12.846000 dts=12813 dts_time=12.813000 duration=33 duration_time=0.033000 convergence_duration=N/A convergence_duration_time=N/A size=27305 pos=27899931 flags=_ [/PACKET] [zaudio.ac3] [PACKET] codec_type=audio stream_index=0 pts=0 pts_time=0.000000 dts=0 dts_time=0.000000 duration=2880 duration_time=0.032000 convergence_duration=N/A convergence_duration_time=N/A size=1024 pos=0 flags=K [/PACKET] [PACKET] codec_type=audio stream_index=0 pts=1154880 pts_time=12.832000 dts=1154880 dts_time=12.832000 duration=2880 duration_time=0.032000 convergence_duration=N/A convergence_duration_time=N/A size=1024 pos=410624 flags=K [/PACKET]
zoutput.mkv seems to be using two reorder frames (more on this later) and the very last packet in storage/coding order is not the last packet in display order, but only the second-to-last in display order. This both explains why the pts-dts-offset of the last packet (according to coding order) only amounts to one frame and why the duration of this file is 12.85s (actually 12.7794s+2*0,03335s = 12.8461s).
Before 9d4fdfe24c731d1880797dee65365154b41c1dea (fixing #4487), the timestamps (video and audio, keeping sync) would be shifted so that the dts is nonnegative which in case of reorder frames means that the very first pts can't be zero. In this case the shifting changed the first pts in done2 to 67ms (equal to two frames; hence me thinking that there are two reorder frames). This also adds 67ms to the duration (because FFmpeg's Matroska muxer uses max(timestamp + duration) (max over all packets) as duration; it does not subtract the lowest timestamp), explaining why the interleaved file is longer.
When demuxing the audio from this file to an elementary stream (which does not have explicit timestamps at all), the shifting can't be preserved at all, hence you have the original duration again.
But when remuxing the video to another Matroska file, the timestamps can be preserved; given that even the dts of the first packet is nonnegative, no further shifting is required and the timestamps of the remuxed video are the same as the timestamps in the interleaved file. The shifting adds the duration of two frames to the video's reported duration, resulting in 12.91s (up from 12.85s (notice that 12.85s was rounded up from a more precise value which is the reason why adding 67ms to the duration results in a reported increase of only 60ms)).
To make this a valid ticket, please provide your failing command line including complete, unedited console output and please consider using a "Code block".