Opened 7 years ago
Closed 6 years ago
#7291 closed defect (fixed)
24bit flac converted to alac, bit-depth atom in output file incorrectly set at 16bit
Reported by: | pssturges | Owned by: | |
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Priority: | normal | Component: | avformat |
Version: | git-master | Keywords: | mov alac |
Cc: | Blocked By: | ||
Blocking: | Reproduced by developer: | no | |
Analyzed by developer: | no |
Description
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
Attachments (1)
Change History (5)
by , 7 years ago
Attachment: | 24bitflac.flac added |
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comment:1 by , 7 years ago
Component: | ffmpeg → avformat |
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Keywords: | mov alac added |
Version: | unspecified → git-master |
comment:2 by , 7 years ago
My understanding of patches sent to developmentlist is that have to had run the regression test which I havne't done.
https://www.ffmpeg.org/developer.html#Submitting-patches
comment:3 by , 7 years ago
The patch is to libavformat/movenc.c but it has been updated since I created the "patch" so line number may be wrong.
1081,1083c1085
< < if (track->par->codec_id == AV_CODEC_ID_FLAC || < track->par->codec_id == AV_CODEC_ID_ALAC) { --- > if (track->par->codec_id == AV_CODEC_ID_FLAC) {
comment:4 by , 6 years ago
Resolution: | → fixed |
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Status: | new → closed |
Fixed in d9a91d58a17ff485a02cd63581ba6f528315c767.
Replying to pssturges:
Then why did you open this ticket?
Please send the patch - made with correct attribution and
git format-patch
- to the development mailing list.