[Libav-user] AC3 -> LPCM -> MPEG2 PES

Andrey Utkin andrey.krieger.utkin at gmail.com
Tue Feb 28 10:59:21 CET 2012

2012/2/28 Pavel Sokolov <pavel at sokolov.me>:
> 27.02.2012 22:11, Andrey Utkin пишет:
>> 2012/2/27 Pavel Sokolov<pavel at sokolov.me>:
>>> How I can convert this data to LPCM?
>> Isn't _that_ called LPCM?

I'm not an expert on media formats, so i can be wrong in some point.
So comments from other people are appreciated.

> My hardware decoder in the embedded device can play sound in the LpcmDvd,
> LpcmHdDvd or LpcmBluRay formats.

First of all, you asked to get LPCM _data_.

>From this, i assume that LPCM is not a container format, but raw data
format. That is exactly what i described above, and what you get after

Now you talk about your hardware decoder... Maybe you should better
ask straightly what your mission is, like "transcode a movie for
playback on dvd-player "CORPORATION MODEL100500".

> I have found function "pcm_bluray_parse_header" in file "pcm-mpeg.c"
> Comment on this function is "Parse the header of a LPCM frame read from a
> MPEG-TS stream"
> So, I think, that LPCM must have some specific header...

(also replying to your newer letter)
Headers belong to containers (file folrmats) and codecs (stream formats).
Obviously, you have to find out which containers and codecs your
hardware supports, and then remux/reencode your existing data to that
formats. Or just mux/encode, if you create data.
Formats "LpcmDvd, LpcmHdDvd or LpcmBluRay" sound strange to me, so
tell us the model and give a link to device specs, so we can figure
out the format names which ffmpeg knows.
Andrey Utkin

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