[MPlayer-dev-eng] Re: [PATCH] v4l capture RC1(?)

[Wander Winkelhorst]

Hi,

> Hi,
>
> > Greetings,
> > this patch adds the following features to V4L module:
> >
> > - multithreaded audio/video buffering (I know mplayer crew hates threads
> > but it seems to me as the only way of doing reliable a/v capture)
> i agree. i don't like threads, but it seems it's th only way here, as v4l
> ioctl blocks and you can't delay more than 1 frames...
>
> > - a/v timebase synchronization (sample count vs. gettimeofday)
> > - "immediate" mode support for mplayer
> > - fixed colorspace stuff - RGB?? and YUY2 modes now work as expected

I don't know exactly what you were trying to fix, but i still need I420 or
else I get those blue faces again

> > - native ALSA audio capture (optional - just #define ALSA_CAPTURE)
>
> sounds cool :)
>
> could others - with v4l card, i don't have any - test it with various
> configuration/hardware and report results?
>

I have a (very cheap) Bt848 TV card, an AthlonXP 1600+ and 320 mb ram,
running Linux 2.4.19

This code works far better than the old. The old code would drop frames
*and sound* while capturing to 640x480. The new code does 786x576 without
dropping any frames or sound. When it does drop frames, it drops a frame every
second or so and not a bunch of frames at once. It never has dropped any audio.
The a/v sync is good as well.

For those intrested in what i use to capture, here is how i start mencoder:

mencoder  -tv on:driver=v4l:width=768:height=576:outfmt=I420 -vc rawi420 -npp
 lb -oac pcm -lavcopts vcodec=mpeg4:vbitrate=1500 -o /tmp/movie.avi

Especially the "-npp lb" option improves video quality greatly :)
I reencode the sound later on: (don't have enough power left to do mp3 encoding
as well)

mencoder /tmp/movie.avi -oac mp3lame -lameopts q=0:aq=0:mode=3 -ovc copy -o
/tmp/movie2.avi

The new code does eats quite a bit of memory though, especially when you set
the gbuffers values of bttv high
(insmod bttv card=39 gbuffers=32 ate 1G of ram when capturing)

Regards,

Wander Winkelhorst

> A'rpi / Astral & ESP-team
>
> --
> Developer of MPlayer, the Movie Player for Linux - http://www.MPlayerHQ.hu
>
> --__--__--
>