[FFmpeg-devel] LATM BitStreamFilter

Paul Kendall paul
Wed Apr 29 10:49:50 CEST 2009

On Wednesday 29 April 2009 08:37:24 pm M?ns Rullg?rd wrote:
> Paul Kendall <paul at kcbbs.gen.nz> writes:
> > Can I ask why LATM is preferred as a bit stream filter rather than
> > as a decoder, or built into the AAC decoder, as ADTS is?
> ADTS is part of the AAC spec.  LATM is not.
Good answer.

So I have an outstanding question regards the LATM bsf.
I have a parser for LATM which uses a specific codec ID, which is set
in mpegts.c.  The parser packetizes the stream. The filter removes
the LATM wrapping and leaves RAW AAC data. How do I now get that
into the AAC codec? Do I set the codec_id in the AVCodecContext
that is passed to the filter function to CODEC_ID_AAC so the
data is routed to the AAC decoder?

Also, not that I may have to make patches to ffmpeg.c so I can
specify an input bsf and/or an output bsf. So the BSF can be applied
after before decoding or after encoding.

Perhaps BSFs need to specify an in or out, unwrap/wrap mode.


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