#10878: Muxing PCM_S24LE Audio Into MP4 Incorrectly Marked as 16-Bit -------------------------------------+------------------------------------- Reporter: | Owner: (none) HyperStryker | Type: defect | Status: new Priority: important | Component: | undetermined Version: git-master | Resolution: Keywords: pcm_s24le | Blocked By: mp4 wav mov muxing ipcm | Blocking: | Reproduced by developer: 0 Analyzed by developer: 0 | -------------------------------------+------------------------------------- Description changed by HyperStryker: Old description:

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, 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 }}}

New description: 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 }}} -- -- Ticket URL: <https://trac.ffmpeg.org/ticket/10878#comment:1> FFmpeg <https://ffmpeg.org> FFmpeg issue tracker

#10878: Muxing PCM_S24LE Audio Into MP4 Incorrectly Marked as 16-Bit -------------------------------------+------------------------------------- Reporter: | Owner: (none) HyperStryker | Type: defect | Status: new Priority: important | Component: | undetermined Version: git-master | Resolution: Keywords: pcm_s24le | Blocked By: mp4 wav mov muxing ipcm | Blocking: | Reproduced by developer: 0 Analyzed by developer: 0 | -------------------------------------+------------------------------------- Comment (by HyperStryker): Replying to [comment:2 Gyan]:

Which ffmpeg version? ffmpeg version 2024-02-15-git-a2cfd6062c-full_build-www.gyan.dev -- Ticket URL: <https://trac.ffmpeg.org/ticket/10878#comment:3> FFmpeg <https://ffmpeg.org> FFmpeg issue tracker

#10878: Muxing PCM_S24LE Audio Into MP4 Incorrectly Marked as 16-Bit -------------------------------------+------------------------------------- Reporter: | Owner: (none) HyperStryker | Type: defect | Status: closed Priority: important | Component: | undetermined Version: git-master | Resolution: fixed Keywords: pcm_s24le | Blocked By: mp4 wav mov muxing ipcm | Blocking: | Reproduced by developer: 0 Analyzed by developer: 0 | -------------------------------------+------------------------------------- Changes (by Marton Balint): * status: new => closed * resolution: => fixed Comment: Fixed in b56b343e43e595c62f204d5797d33645f4c46d96 and 35dc129940246088d376e5c343b8076ffbea2b64. -- Ticket URL: <https://trac.ffmpeg.org/ticket/10878#comment:5> FFmpeg <https://ffmpeg.org> FFmpeg issue tracker