[FFmpeg-trac] #7291(ffmpeg:new): 24bit flac converted to alac, bit-depth atom in output file incorrectly set at 16bit
FFmpeg
trac at avcodec.org
Sun Jul 1 14:17:00 EEST 2018
#7291: 24bit flac converted to alac, bit-depth atom in output file incorrectly set
at 16bit
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Reporter: pssturges | Type: defect
Status: new | Priority: normal
Component: ffmpeg | Version: unspecified
Keywords: | Blocked By:
Blocking: | Reproduced by developer: 0
Analyzed by developer: 0 |
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Summary of the bug: 24bit flac converted to alac, bit-depth atom in output
file incorrectly set at 16bit not 24bit
How to reproduce:
{{{
% ffmpeg -i 24bitflac.flac -y -map 0:0 -c:a:0 alac 24bitalac.m4a
ffmpeg version 2.8.14-0ubuntu0.16.04.1
mp4file --dump 24bitalac.m4a | grep sample
"24bitalac.m4a": sampleSize = 16 (0x0010)
"24bitalac.m4a": sampleSize = 0 (0x00000000)
"24bitalac.m4a": sampleCount = 6096 (0x000017d0)
}}}
This causes the resultant file to play as white noise in some players as
they attempt to play it as 16bit file. Logitech Media Server is one such
player.
An extensive investigation of this issue can be found on the slim devices
forum found here:
https://forums.slimdevices.com/showthread.php?102059-24-bit-ALAC-files-
being-truncated-to-16-bit
Forum member 'bpa' has suggested a patch in that thread which I have
tested and found to correct the problem
--
Ticket URL: <https://trac.ffmpeg.org/ticket/7291>
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