[FFmpeg-trac] #11576(avcodec:new): amrwb constant bitrate wrong time estimation

[FFmpeg]

#11576: amrwb constant bitrate wrong time estimation
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             Reporter:  LanMarc77    |                    Owner:  (none)
                 Type:  defect       |                   Status:  new
             Priority:  important    |                Component:  avcodec
              Version:  unspecified  |               Resolution:
             Keywords:               |               Blocked By:
             Blocking:               |  Reproduced by developer:  0
Analyzed by developer:  0            |
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Comment (by LanMarc77):

 Using this file https://github.com/anars/blank-audio/blob/master/30
 -minutes-of-silence.mp3 and the static builds from here:
 https://johnvansickle.com/ffmpeg/ I could verify that ffmpeg 4.4.1 and
 7.0.2 encode the 30minutes silence using -acodec amr_wb -ar 16000 -ac 1
 -ab 23850 into the exact same file. sha256sums match.
 But ffprobe from 4.4.1 shows the correct 00:30:00.30 while version 7.0.2
 shows 00:31:01.33.
 Judging by these numbers it seems always 3.3% too long.
 This pretty much aligns with the frame overhead. One frame for the above
 amr-wb bitsize is 61bytes containing 2bytes frame overhead and 59bytes
 data. 61/59 also boils down to 3.3%.
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Ticket URL: <https://trac.ffmpeg.org/ticket/11576#comment:1>
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