[FFmpeg-devel] [PATCH] DVB LATM parser

[Jai Menon]

On Sun, Feb 1, 2009 at 4:37 AM, Paul Kendall <paul at kcbbs.gen.nz> wrote:
> Micheal,
> Sorry for the long delay in this! Been really busy with other things.
> Now there is a bit of noise on the MythTV lists about this so I thought it
> time that I get back to it.
>
> On Thursday 18 September 2008 06:24:48 Michael Niedermayer wrote:
>> Hi
>>
>> On Wed, Sep 17, 2008 at 04:57:46PM +1200, Paul Kendall wrote:
>> > On Wednesday 17 September 2008 12:51:18 Michael Niedermayer wrote:
>> > > On Fri, Jul 04, 2008 at 09:28:37AM +1200, Paul Kendall wrote:
>> > > > On Thursday 03 July 2008 22:16:56 Paul Kendall wrote:
>> > > > > Hi attached is a patch that provides a AAC LATM parser
>> > > > > CODEC_ID_AAC_LATM I have been working on. The libfaad decoder is
>> > > > > also patched to provide another codec the decoding for this codec
>> > > > > id. There are minor patches to mpeg.c & mpegts.c to send stream id
>> > > > > 0x11 to this codec id.
>> > > > >
>> > > > > With this patch I can get audio working perfectly for NZ DVB-T
>> > > > > using the stock unpatched libfaad2 library.
>> > > > >
>> > > > > I would welcome comments and suggestions so this can be included in
>> > > > > the ffmpeg codebase.
>> > > > >
>> > > > > Cheers,
>> > > > > Paul Kendall
>> > > >
>> > > > Doh!
>> > > > I missed a vital part of the patch! Putting the codec in the
>> > > > allcodecs.c file! Heres a modified patch.
>> > >
>> > > I think a parser is not the correct place to remove the LATM stuff. A
>> > > parser should only split things into frames and extract information,
>> > > not remove information.
>> > > This for example is important if one wants to preserve the LATM and mux
>> > > it into another container.
>> > > LATM could be removed in a bitstream filter ....
>> >
>> > Ok, I can look into this. Is there any docs on this.
>>
>> well ... the source code :)
>> but you can ask questions here if you have any, also keep in mind if the
>> bitstream filter API has any problems it could be changed ...
>>
>> Also note that a LATM parser or some changes to the AAC parser might still
>> be required even with a bitstream filter, otherwise the AAC parser will
>> likely be confused by the LATM stuff ...
>>
> The parser needs to be modified to handle the LATM wrapping and packetize the
> stream. Should the parser also set the extradata so the decoder can use that
> to set the channels, sample rate & sample size? or should this be left to the
> bitstream filter?
>
> The bitstream filter should just check the LATM wrapping and remove if present.
>
> The decoder then gets raw AAC data and all the parameters have been set by the
> parser and so it should all work fine.
>
> Is that the plan?

Hi Paul, Is there any update on this? the approach sounds about right

-- 
Regards,

Jai