[FFmpeg-user] Dolby E decoder

Paul B Mahol onemda at gmail.com
Mon Sep 11 11:52:05 EEST 2017


On 9/11/17, Mike Brown <brown at mrvideo.vidiot.com> wrote:
> On Mon, Sep 11, 2017 at 09:23:36AM +0200, Fr?d?ric Busnel-Joncour wrote:
>> > Looks like you need to resample audio to sample rate ac3 supports.
>>
>> I've just tried to convert two different Dolby E source from wav to u8,
>> then ffprobe recognize them as a Dolby E stream, but it says that they're
>> 44800Hz, I guess it should be 48000Hz. Perhaps there's a bug here ?
>
> Here are the results that I get:
>
> ffprobe out.dat
> ffprobe version N-87196-g6cadbb1 Copyright (c) 2007-2017 the FFmpeg
> developers
>   built with gcc 7.1.0 (GCC)
>   configuration: --enable-gpl --enable-version3 --enable-cuda --enable-cuvid
> --enable-d3d11va --enable-dxva2 --enable-libmfx --enable-nvenc
> --enable-avisynth --enable-bzlib --enable-fontconfig --enable-frei0r
> --enable-gnutls --enable-iconv --enable-libass --enable-libbluray
> --enable-libbs2b --enable-libcaca --enable-libfreetype --enable-libgme
> --enable-libgsm --enable-libilbc --enable-libmodplug --enable-libmp3lame
> --enable-libopencore-amrnb --enable-libopencore-amrwb --enable-libopenh264
> --enable-libopenjpeg --enable-libopus --enable-librtmp --enable-libsnappy
> --enable-libsoxr --enable-libspeex --enable-libtheora --enable-libtwolame
> --enable-libvidstab --enable-libvo-amrwbenc --enable-libvorbis
> --enable-libvpx --enable-libwavpack --enable-libwebp --enable-libx264
> --enable-libx265 --enable-libxavs --enable-libxvid --enable-libzimg
> --enable-lzma --enable-zlib
>   libavutil      55. 74.100 / 55. 74.100
>   libavcodec     57.105.100 / 57.105.100
>   libavformat    57. 81.100 / 57. 81.100
>   libavdevice    57.  8.100 / 57.  8.100
>   libavfilter     6.101.100 /  6.101.100
>   libswscale      4.  7.103 /  4.  7.103
>   libswresample   2.  8.100 /  2.  8.100
>   libpostproc    54.  6.100 / 54.  6.100
> [dolby_e @ 000000000068bfc0] Stream has 2 programs (configuration 0),
> channels will be output in native order.
> Input #0, s337m, from 'out.dat':
>   Duration: N/A, bitrate: N/A
>     Stream #0:0: Audio: dolby_e, 53706 Hz, 7.1, fltp
>
>
> ffprobe out.wav
> ffprobe version N-87196-g6cadbb1 Copyright (c) 2007-2017 the FFmpeg
> developers
>   built with gcc 7.1.0 (GCC)
>   configuration: --enable-gpl --enable-version3 --enable-cuda --enable-cuvid
> --enable-d3d11va --enable-dxva2 --enable-libmfx --enable-nvenc
> --enable-avisynth --enable-bzlib --enable-fontconfig --enable-frei0r
> --enable-gnutls --enable-iconv --enable-libass --enable-libbluray
> --enable-libbs2b --enable-libcaca --enable-libfreetype --enable-libgme
> --enable-libgsm --enable-libilbc --enable-libmodplug --enable-libmp3lame
> --enable-libopencore-amrnb --enable-libopencore-amrwb --enable-libopenh264
> --enable-libopenjpeg --enable-libopus --enable-librtmp --enable-libsnappy
> --enable-libsoxr --enable-libspeex --enable-libtheora --enable-libtwolame
> --enable-libvidstab --enable-libvo-amrwbenc --enable-libvorbis
> --enable-libvpx --enable-libwavpack --enable-libwebp --enable-libx264
> --enable-libx265 --enable-libxavs --enable-libxvid --enable-libzimg
> --enable-lzma --enable-zlib
>   libavutil      55. 74.100 / 55. 74.100
>   libavcodec     57.105.100 / 57.105.100
>   libavformat    57. 81.100 / 57. 81.100
>   libavdevice    57.  8.100 / 57.  8.100
>   libavfilter     6.101.100 /  6.101.100
>   libswscale      4.  7.103 /  4.  7.103
>   libswresample   2.  8.100 /  2.  8.100
>   libpostproc    54.  6.100 / 54.  6.100
> Input #0, wav, from 'out.wav':
>   Metadata:
>     encoder         : Lavf57.81.100
>   Duration: 00:00:18.92, bitrate: 6874 kb/s
>     Stream #0:0: Audio: pcm_s16le ([1][0][0][0] / 0x0001), 53706 Hz, 7.1,
> s16, 6874 kb/s
>
>
> Notice that I get 53706 Hz, 7.1 and 16bits.  The audio is 5.1.  It is for
> broacast, so it is 48kHz.
>
>> But I unfortunately can't use ffplay to play it, there a compilation bug
>> on my fedora 24 box with this last ffmpeg release (very annoying by the
>> way, I must investigate it).
>>
>
> I do not have the audio connected on my Win7 box.  I still tried it and it
> complained trying to set up 8, 6 and 4 channels.  The 53706 Hz attempted as
> well.

FFplay is broken demo. Download mpv.

>
> MB
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