Opened 8 months ago
Closed 7 months ago
#10878 closed defect (fixed)
Muxing PCM_S24LE Audio Into MP4 Incorrectly Marked as 16-Bit
Reported by: | HyperStryker | Owned by: | |
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Priority: | important | Component: | undetermined |
Version: | git-master | Keywords: | pcm_s24le mp4 wav mov muxing ipcm |
Cc: | Blocked By: | ||
Blocking: | Reproduced by developer: | no | |
Analyzed by developer: | no |
Description (last modified by )
Summary of the bug:
When muxing an H264-encoded video in a .MOV container with a .WAV file containing PCM_S24LE audio to an .MP4 container (discarding original video audio), the resulting file purportedly contains PCM_S24LE audio, but is incorrectly marked as 16-bit when checking the resulting .MP4 file in Mediainfo:
Audio ID : 2 Format : PCM Format settings : Little / Signed Codec ID : ipcm Duration : 56 min 5 s Bit rate mode : Constant Bit rate : 1 536 kb/s Maximum bit rate : 2 304 kb/s Channel(s) : 2 channels Channel layout : L R Sampling rate : 48.0 kHz Bit depth : 16 bits Stream size : 924 MiB (8%) Default : Yes Alternate group : 1
FFmpeg in the command line shows the resulting audio still in the PCM_S24LE format when muxing (using an PCM_S24LE audio-only .MOV file instead of .WAV, made no practical difference):
Stream #0:1(eng): Audio: pcm_s24le (ipcm / 0x6D637069), 48000 Hz, stereo, s32 (24 bit), 2304 kb/s (default) Metadata: creation_time : 2024-02-21T04:54:45.000000Z handler_name : Apple Sound Media Handler vendor_id : timecode : 00:00:00:00
Further, to verify it was FFmpeg and not Mediainfo, when extracting/stream-copying the audio from the .MP4 file back into a .WAV file, FFmpeg notes:
[wav @ 000002532f935a80] requested bits_per_coded_sample (16) and actually stored (24) differ
This lined up with me checking the same .MP4 file in Adobe Audition, which reported the file as containing 24-bit audio instead of 16-bit.
How to reproduce:
Muxing .MOV and .WAV to .MP4
ffmpeg -i in1.mov -i in2.wav -map 0:v -map 1:a -c copy out.mp4
Stream copying back to .WAV
ffmpeg -i out.mp4 -map 0:a -c copy out2.wav
Change History (5)
comment:1 by , 8 months ago
Description: | modified (diff) |
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follow-up: 3 comment:2 by , 8 months ago
comment:3 by , 8 months ago
Replying to Gyan:
Which ffmpeg version?
ffmpeg version 2024-02-15-git-a2cfd6062c-full_build-www.gyan.dev
comment:4 by , 8 months ago
comment:5 by , 7 months ago
Resolution: | → fixed |
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Status: | new → closed |
Which ffmpeg version?