[FFmpeg-trac] #6841(undetermined:new): 1ms gap in WebM Opus files encoded with ffmpeg

[FFmpeg]

#6841: 1ms gap in WebM Opus files encoded with ffmpeg
-------------------------------------+-------------------------------------
             Reporter:  ntrrgc       |                    Owner:
                 Type:  defect       |                   Status:  new
             Priority:  normal       |                Component:
              Version:  unspecified  |  undetermined
             Keywords:               |               Resolution:
             Blocking:               |               Blocked By:
Analyzed by developer:  0            |  Reproduced by developer:  0
-------------------------------------+-------------------------------------

Comment (by ntrrgc):

 Replying to [comment:1 cehoyos]:
 > Is the issue reproducible with {{{-f lavfi -i sine=d=1}}}?
 Yes.

 > Please test current FFmpeg git head and provide the command line you
 tested together with the complete, uncut console output to make this a
 valid ticket.

 {{{
 % ~/Apps/ffmpeg-bin/ffmpeg -f lavfi -i sine=d=1 -c:a libopus buggy-
 timestamps.webm
 ffmpeg version N-89088-gce001bb8fc Copyright (c) 2000-2017 the FFmpeg
 developers
   built with gcc 7 (GCC)
   configuration: --enable-libopus --prefix=/home/ntrrgc/Apps/ffmpeg-build
 --bindir=/home/ntrrgc/Apps/ffmpeg-bin
   libavutil      56.  0.100 / 56.  0.100
   libavcodec     58.  3.102 / 58.  3.102
   libavformat    58.  2.100 / 58.  2.100
   libavdevice    58.  0.100 / 58.  0.100
   libavfilter     7.  0.101 /  7.  0.101
   libswscale      5.  0.101 /  5.  0.101
   libswresample   3.  0.101 /  3.  0.101
 Input #0, lavfi, from 'sine=d=1':
   Duration: N/A, start: 0.000000, bitrate: 705 kb/s
     Stream #0:0: Audio: pcm_s16le, 44100 Hz, mono, s16, 705 kb/s
 File 'buggy-timestamps.webm' already exists. Overwrite ? [y/N] y
 Stream mapping:
   Stream #0:0 -> #0:0 (pcm_s16le (native) -> opus (libopus))
 Press [q] to stop, [?] for help
 [libopus @ 0x2a3b480] No bit rate set. Defaulting to 64000 bps.
 Output #0, webm, to 'buggy-timestamps.webm':
   Metadata:
     encoder         : Lavf58.2.100
     Stream #0:0: Audio: opus (libopus), 48000 Hz, mono, s16, 64 kb/s
     Metadata:
       encoder         : Lavc58.3.102 libopus
 [Parsed_sine_0 @ 0x2a24c20] EOF timestamp not reliable
 size=      10kB time=00:00:01.01 bitrate=  80.1kbits/s speed=42.4x
 video:0kB audio:9kB subtitle:0kB other streams:0kB global headers:0kB
 muxing overhead: 11.461192%

 % mkvinfo -v /tmp/buggy-timestamps.webm | head -n 50
 + EBML head
 |+ EBML version: 1
 |+ EBML read version: 1
 |+ EBML maximum ID length: 4
 |+ EBML maximum size length: 8
 |+ Doc type: webm
 |+ Doc type version: 4
 |+ Doc type read version: 2
 + Segment, size 2312240
 |+ Seek head (subentries will be skipped)
 |+ EbmlVoid (size: 185)
 |+ Segment information
 | + Timestamp scale: 1000000
 | + Multiplexing application: Lavf57.71.100
 | + Writing application: Lavf57.71.100
 | + Duration: 192.434s (00:03:12.434)
 |+ Segment tracks
 | + A track
 |  + Track number: 1 (track ID for mkvmerge & mkvextract: 0)
 |  + Track UID: 1
 |  + Lacing flag: 0
 |  + Language: und
 |  + Codec ID: A_OPUS
 |  + Codec delay: 6.500ms (6500000ns)
 |  + Seek pre-roll: 80.000ms (80000000ns)
 |  + Track type: audio
 |  + Audio track
 |   + Channels: 2
 |   + Sampling frequency: 48000
 |   + Bit depth: 16
 |  + CodecPrivate, length 19
 |+ Cluster
 | + Cluster timestamp: 0.000s
 | + SimpleBlock (key, track number 1, 1 frame(s), timestamp 0.000s =
 00:00:00.000)
 |  + Frame with size 389
 | + SimpleBlock (key, track number 1, 1 frame(s), timestamp 0.021s =
 00:00:00.021)
 |  + Frame with size 212
 | + SimpleBlock (key, track number 1, 1 frame(s), timestamp 0.041s =
 00:00:00.041)
 |  + Frame with size 180
 | + SimpleBlock (key, track number 1, 1 frame(s), timestamp 0.061s =
 00:00:00.061)
 |  + Frame with size 58
 | + SimpleBlock (key, track number 1, 1 frame(s), timestamp 0.081s =
 00:00:00.081)
 |  + Frame with size 64
 | + SimpleBlock (key, track number 1, 1 frame(s), timestamp 0.101s =
 00:00:00.101)
 |  + Frame with size 71
 | + SimpleBlock (key, track number 1, 1 frame(s), timestamp 0.121s =
 00:00:00.121)
 |  + Frame with size 65
 | + SimpleBlock (key, track number 1, 1 frame(s), timestamp 0.141s =
 00:00:00.141)
 |  + Frame with size 64
 | + SimpleBlock (key, track number 1, 1 frame(s), timestamp 0.161s =
 00:00:00.161)

 % ~/Apps/ffmpeg-bin/ffmpeg -version
 ffmpeg version N-89088-gce001bb8fc Copyright (c) 2000-2017 the FFmpeg
 developers
 built with gcc 7 (GCC)
 configuration: --enable-libopus --prefix=/home/ntrrgc/Apps/ffmpeg-build
 --bindir=/home/ntrrgc/Apps/ffmpeg-bin
 libavutil      56.  0.100 / 56.  0.100
 libavcodec     58.  3.102 / 58.  3.102
 libavformat    58.  2.100 / 58.  2.100
 libavdevice    58.  0.100 / 58.  0.100
 libavfilter     7.  0.101 /  7.  0.101
 libswscale      5.  0.101 /  5.  0.101
 libswresample   3.  0.101 /  3.  0.101

 }}}

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Ticket URL: <https://trac.ffmpeg.org/ticket/6841#comment:2>
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