[FFmpeg-devel] [PATCH] Set CODEC_CAP_SUBFRAMES for adpcm decoders
Fri Jan 22 19:21:56 CET 2010
On Fri, Jan 22, 2010 at 04:13:03PM +0000, M?ns Rullg?rd wrote:
> Michael Niedermayer <michaelni at gmx.at> writes:
> > On Thu, Jan 21, 2010 at 04:42:27PM +0000, M?ns Rullg?rd wrote:
> >> Michael Niedermayer <michaelni at gmx.at> writes:
> >> > 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
> >> General in this context means something that is always true. If there
> >> exist adpcm streams with non-byte-aligned frames, they cannot be split
> >> in the general case, which includes these streams.
> >> It may be that in the _majority_ of streams can be split, but unless
> >> there's an easy way to determine this without actually trying it, I
> >> don't think we should be requiring it.
> > We have 27 adpcm decoders, some of them can be split into frames, some
> > do not know a concept of frames != packets some maybe cannot be split.
> > They all use an AVCodec struct build out of a macro to which you added
> > the flag, thus effectively adding it to 27 different codecs, some of
> > which are not even capable of returning subframes no matter what is in
> > the bitstream.
> If someone tells me which of decoders need the flag I will fix it.
id guess none, all that allow multiple frames likely can be split trivially
Michael GnuPG fingerprint: 9FF2128B147EF6730BADF133611EC787040B0FAB
I hate to see young programmers poisoned by the kind of thinking
Ulrich Drepper puts forward since it is simply too narrow -- Roman Shaposhnik
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