[MPlayer-dev-eng] [PATCH] [TEST AFILTER] Encode ac3 at runtime using lavc

Ulion ulion2002 at gmail.com
Thu Nov 22 13:53:57 CET 2007


2007/11/22, Reimar Döffinger <Reimar.Doeffinger at stud.uni-karlsruhe.de>:
> Hello,
> On Thu, Nov 22, 2007 at 12:34:03AM +0800, Ulion wrote:
> [...]
> > > So the only thing that is missing IMO is documenting that the AC3/DTS
> > > etc. formats actually mean those wrapped in IEC-headers.
> >
> > Currently yes, but it's better confirm what ao_mpegpes.c mean to use
> > the AC-3 format.
>
> The problem is that the current filter chain has no notion of packets/frames
> (and thus can not guarantee to keep the boundaries), but even ao_mpegpes.c
> almost needs the data split this way.

Oh, the ao_mpegpes seems need the frame info to split or do it by
itself. I do not even know what's this ao's function.

> So unless you want to "fix" the whole filter stuff to use packets
> (questionable if this is even such a good idea) we have either the
> option of supporting only IEC and those aos who need it must remove it
> (while still using the info to split by frames),

Then we can treat the iec package as somekind of package protocol to
mark frames, and let the ao decide what to do for encoded audio
streams (have to be supported by iec),

> or we support non-IEC
> and those aos probably have to implement packetizing.
> Which brings me to why I think that it is _pointless_ to support
> non-IEC, and thus we need no flag to indicate it.
>

Add non-IEC formats does not mean support them, only aos need them
(without frame info) could support non-IEC formats, others just keep
only support IEC format.
An format converter should be auto-inserted to convert non-IEC formats
to IEC format, does the current hwac3's job.

> > btw: any suggestion for generate the last ac3 frame of at the audio
> > track end, it has not enough bytes to triger the encode action in
> > current code.
>
> If nothing else, use an AF_CONTROL that indicates the end of the audio
> stream.

Is there any EOF CONTROL send to audio filters when the ad sent all audio bytes?

>
> Greetings,
> Reimar Döffinger
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>


-- 
Ulion



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