[mpeg2] Re: Setting Audio, Video, and PCR PIDs

[Andrew de Quincey <adq_dvb@lidskialf.net>]

On Thursday 13 May 2004 11:59, Luca Abeni wrote:
> Hi all,
>
> the attached patch permits to specify the PIDs to be used, instead of
> using the hardcoded ones. I lightly tested it, and everything seems to
> work.
>
> I added three fields to the mpeg_params structure, I hope it is ok...
> The I got the code for computing the CRC32 from ffmpeg, that is licensed
> under LGPL, hence I assume it is ok... I don't know if the authors' list
> at the beginning of the file must be updated (I think the crc32 code and
> table is by Fabrice Bellard). If yes, let me know, and I'll send an
> updated patch. Otherwise, if you alread have some crc32 code... ;-)

We should probably use the in-kernel crc32 library...

> The patch also fixes two things that I believe are typos:
> 1) if (params->bitrate_mode == MPEG_BITRATE_MODE_MAX &&
>                     params->video_target_bitrate <=
> params->video_max_bitrate)
> does not seem to be correct... Maybe is should be
> if (params->bitrate_mode == MPEG_BITRATE_MODE_VBR &&
>                     params->video_target_bitrate >=
> params->video_max_bitrate)
>
> 2) the check on params->video_max_bitrate was performed even in the CBR
> case
>
> I apologize if I misunderstood the code...

Nice one! I'll have a look later; in the middle of fixing DVB stuff right now.

I have a slightly updated version with some better default bitrate parameters 
and tweaks... should I merge our two patches together & repost?

> Now, I am thinking about adding code for setting the video format (it is
> currently hardcoded to D1). Is it ok to add yet another field to
> mpeg_params?

Fine by me - if you can, try and make it flexible; I was aiming for something 
that used by other MPEG encoders at a future date.