[FFmpeg-trac] #6607(ffplay:new): ffplay has difficulty decoding 4.0 PCM

FFmpeg trac at avcodec.org
Wed Aug 23 12:59:50 EEST 2017


#6607: ffplay has difficulty decoding 4.0 PCM
-----------------------------------+---------------------------------------
             Reporter:  kieranjol  |                     Type:  defect
               Status:  new        |                 Priority:  normal
            Component:  ffplay     |                  Version:  unspecified
             Keywords:             |               Blocked By:
             Blocking:             |  Reproduced by developer:  0
Analyzed by developer:  0          |
-----------------------------------+---------------------------------------
 Summary of the bug:
 ffplay and VLC have issues playing 4.0 PCM audio, whether in WAV, MOV or
 MKV containers. When making `sine` waves with `lavfi`, ffplay produces
 silence for 4.0, though 2, 5, 6 channel audio is played back OK. VLC
 produces throbbing, distoreted audio but that's outside of the scope of
 this issue I guess.
 How to reproduce:
 Generate a sine wave with ffmpeg and then play it back with ffplay.
 {{{
 ./ffmpeg -f lavfi -i "sine=frequency=1000:duration=5:sample_rate=48000"
 -ac 4 -c:a pcm_s24le test.wav
 ffmpeg version N-87034-geca2a49 Copyright (c) 2000-2017 the FFmpeg
 developers
   built with Apple LLVM version 7.3.0 (clang-703.0.31)
   configuration:
   libavutil      55. 74.100 / 55. 74.100
   libavcodec     57.103.100 / 57.103.100
   libavformat    57. 76.100 / 57. 76.100
   libavdevice    57.  7.101 / 57.  7.101
   libavfilter     6.100.100 /  6.100.100
   libswscale      4.  7.102 /  4.  7.102
   libswresample   2.  8.100 /  2.  8.100
 Input #0, lavfi, from 'sine=frequency=1000:duration=5:sample_rate=48000':
   Duration: N/A, start: 0.000000, bitrate: 768 kb/s
     Stream #0:0: Audio: pcm_s16le, 48000 Hz, mono, s16, 768 kb/s
 File 'test.wav' already exists. Overwrite ? [y/N] y
 Stream mapping:
   Stream #0:0 -> #0:0 (pcm_s16le (native) -> pcm_s24le (native))
 Press [q] to stop, [?] for help
 Output #0, wav, to 'test.wav':
   Metadata:
     ISFT            : Lavf57.76.100
     Stream #0:0: Audio: pcm_s24le ([1][0][0][0] / 0x0001), 48000 Hz, 4.0,
 s32, 4608 kb/s
     Metadata:
       encoder         : Lavc57.103.100 pcm_s24le
 size=    2813kB time=00:00:05.00 bitrate=4608.2kbits/s speed= 432x
 video:0kB audio:2812kB subtitle:0kB other streams:0kB global headers:0kB
 muxing overhead: 0.003542%

 ./ffplay test.wav
 ffplay version N-87034-geca2a49 Copyright (c) 2003-2017 the FFmpeg
 developers
   built with Apple LLVM version 7.3.0 (clang-703.0.31)
   configuration:
   libavutil      55. 74.100 / 55. 74.100
   libavcodec     57.103.100 / 57.103.100
   libavformat    57. 76.100 / 57. 76.100
   libavdevice    57.  7.101 / 57.  7.101
   libavfilter     6.100.100 /  6.100.100
   libswscale      4.  7.102 /  4.  7.102
   libswresample   2.  8.100 /  2.  8.100
 Input #0, wav, from 'test.wav':
   Metadata:
     encoder         : Lavf57.76.100
   Duration: 00:00:05.00, bitrate: 4608 kb/s
     Stream #0:0: Audio: pcm_s24le ([1][0][0][0] / 0x0001), 48000 Hz, 4.0,
 s32 (24 bit), 4608 kb/s
    3.46 M-A: -0.000 fd=   0 aq=  577KB vq=    0KB sq=    0B f=0/0

 }}}
 Patches should be submitted to the ffmpeg-devel mailing list and not this
 bug tracker.

--
Ticket URL: <https://trac.ffmpeg.org/ticket/6607>
FFmpeg <https://ffmpeg.org>
FFmpeg issue tracker


More information about the FFmpeg-trac mailing list