[FFmpeg-devel] [RFC/PATCH 6/8] tidsp: add mp4v configuration

[Michael Niedermayer]

On Tue, Sep 07, 2010 at 12:44:12PM +0300, Felipe Contreras wrote:
> On Tue, Sep 7, 2010 at 5:45 AM, Ronald S. Bultje <rsbultje at gmail.com> wrote:
> > On Sun, Sep 5, 2010 at 6:15 PM, Felipe Contreras
> > <felipe.contreras at gmail.com> wrote:
> >> +struct mp4vdec_args {
> >> + ? ? ? uint32_t size;
> >> + ? ? ? uint16_t num_streams;
> >> +
> >> + ? ? ? uint16_t in_id;
> >> + ? ? ? uint16_t in_type;
> >> + ? ? ? uint16_t in_count;
> >> +
> >> + ? ? ? uint16_t out_id;
> >> + ? ? ? uint16_t out_type;
> >> + ? ? ? uint16_t out_count;
> >> +
> >> + ? ? ? uint16_t reserved;
> >> +
> >> + ? ? ? uint32_t max_width;
> >> + ? ? ? uint32_t max_height;
> >> + ? ? ? uint32_t color_format;
> >> + ? ? ? uint32_t max_framerate;
> >> + ? ? ? uint32_t max_bitrate;
> >> + ? ? ? uint32_t endianness;
> >> + ? ? ? uint32_t profile;
> >> + ? ? ? int32_t max_level;
> >> + ? ? ? uint32_t mode;
> >> + ? ? ? int32_t preroll;
> >> + ? ? ? uint32_t display_width;
> >> +};
> >
> > What are all these?
> 
> These are arguments needed to start the DSP algorithm.
> 
> > Why are they specifically-sized fields? Can you
> > document some of them? Do they describe bitstream (in which case they
> > should likely be read from AVCodecContext rather than be copied here,
> > no?)? Do they describe the system (e.g. endianness, in which case you
> > shouldn't make it a variable since it's highly unlikely that halfway
> > the movie, the endianness of the running system will switch)? Do they
> > describe the hardware (max_bitrate - is that static or configurable or
> > dependent on hardware/driver version?)?
> 
> You can think of a DSP algorithm as a normal program, written in C
> code even, except that it runs in a separate processor (C64x). You
> communicate to it through the tidspbridge driver, and each algorithm
> requires different arguments, but of course the fields have to have
> specific sizes.

one would expect that such a communication struct be in a header and
documented
[...]
--
Michael     GnuPG fingerprint: 9FF2128B147EF6730BADF133611EC787040B0FAB

While the State exists there can be no freedom; when there is freedom there
will be no State. -- Vladimir Lenin
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