[mpeg2] Re: Question about the MPEX encoder board

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

On Wednesday 21 April 2004 09:47, you wrote:
> Hello,
>
> I need an MPEG2 encoder board supported by linux, and I was thinking
> about getting an MPEX board:
> http://linuxtv.org/mpeg2/mpex.xml
>
> However, the above cited web page is a little bit scary: " The driver is
> in an early stage. TS output works but no setting of encoding parameters
> like bitrate or GOP-size...". Is the web page just outdated, or is the
> driver still not mature enough? I dowloaded the driver (mpex.tar.gz),
> and it seems to be pretty old (23-Apr-2003... Almost 1 year old). Is
> this the latest version? I see that it seems to be the V4L2 saa7134
> driver; is the MPEX board supported by recent snapshots from
> http://linux.bytesex.org/v4l2 ?

Yeah, thats the place... the page on linuxtv.org is out of date.

> I am wondering if someone has an MPEX board, and if he is able to set
> the encoding parameters (CBR vs VBR, bitrate, GOP size). MPEG2 TS would
> be fine (no need for PS). Also, how is the quality of the encoded
> streams (compared for example to a KFIR)?

The MPEX is MUCH better. They don't gradually drift out of AV sync within a 
few days. We've  had them deployed on multiple sites for months. The only 
problem with them is they don't like it when the video feed is unplugged; you 
generally have to restart the userspace program reading from the card if this 
happens.

Video quality looks good.

You are able to set the bitrate parameters, but be warned that it seems quite 
sensitive to the exact parameters used; if you get them wrong, you get weird 
breakup effects.