[FFmpeg-devel] [PATCH] Set CODEC_CAP_SUBFRAMES for adpcm decoders

Michael Niedermayer michaelni
Thu Jan 21 16:36:47 CET 2010

On Thu, Jan 21, 2010 at 02:12:26PM +0000, M?ns Rullg?rd wrote:
> Benjamin Larsson <banan at ludd.ltu.se> writes:
> > M?ns Rullg?rd wrote:
> >> I thought adpcm was one of those non-byte-aligned codecs, at least
> >> some variants.
> >
> > It is.
> Which means frame-splitting is not generally possible.

ADPCM in general comes in frames with a header of an initial sample
and a series of adaptive delta coded fixed length (generally
4 bit) symbols
but there are exceptions. The general case though certainly can be split
into frames. And quite trivially so as they are constant size, its 34bytes
per channel according to the source for CODEC_ID_ADPCM_IMA_QT.
Is there something with this file that makes this impossible or unwanted?
If theres a performance loss due to the smaller packets we surely could
add some flag to indicate that the spliting should be ommited where its
not needed ...


Michael     GnuPG fingerprint: 9FF2128B147EF6730BADF133611EC787040B0FAB

It is not what we do, but why we do it that matters.
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