[FFmpeg-user] Dolby E decoder

Paul B Mahol onemda at gmail.com
Fri Sep 8 10:34:50 EEST 2017


On 9/8/17, Mike Brown <brown at mrvideo.vidiot.com> wrote:
> On Fri, Sep 08, 2017 at 12:54:12AM +0200, Carl Eugen Hoyos wrote:
>> (Sorry, my knowledge of SMPTE 337M is limited but I know that so far,
>> this is the only "format" for which FFmpeg supports Dolby-E, and that
>> adding support for other formats will be possible but hasn't been
>> done yet.)
>
> From what I understand, reading the synopsis of SMPTE-337M, is that it is
> not a container specifically for Dolby-E.  I couldn't anything out of it to
> indicate that it can even handle Dolby-E.
>
> That said, I do deal with SMPTE-302M, which is the spec for which Dolby-E is
> applied to Transport Streams.  In my case satellite feeds (not for the
> consumer).  The spec talks about MPEG-2 TS streams, but it applies to H.264
> streams as well.
>
> Right now, I use ffmpeg to extract the stream into a 2-ch WAVE file, in
> which
> I use in another program to extract the audio into 6 mono WAVE files.  I
> then
> use ffmpeg to encode a AC3 file.
>
> Are you saying that I can use ffmpeg and get to a final ac3 file in a single
> step?

No, you would need to copy audio to raw container, this raw container would be
then detected as Dolby-E.

ffmpeg -i input.wav -c:a copy -f u8 out.u8

ffmpeg -i out.u8 -c:a ac3 .....


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