[Mplayer-dvb] Re: video newbie wants to help, advice needed

[Frank Klingenhoefer]

On Wed, Jan 23, 2002 at 02:19:19AM +0100, Alexander Neundorf wrote:
> Hi,
> 
> I'm very new to this video stuff (not programming), but now I have a lot of 
> time to work on it :-)
> 
> Well, basically I want to record data from my analog tv card and feed it 
> somehow into the dvb card, so that it will be displayed on the tv with the 
> nice translucent OSD.
> 
> As far as I am until now, mencoder is able to record video from a v4l device, 
> but not audio yet.
> This is the first point where I'd like to work.
> Can somebody give me some hints how to start, what to consider ?
> 
> Then, when this is done, AFAIK it has to be encoded into a MPEG2 PES, and 
> this can be fed into the Siemens dvb card.
> 
> This would have to happen in realtime. 
> I have a 1 GHz Athlon here.
[...]

Hi,
I have tested the following thing:

debian:/home/frank/# mp1e -m3 -s 352x288 -b 3000 -p /dev/dsp1 -vv|\
buffer -s 16kB -p 75|ntuxplayer -o

Opened OSS PCM device /dev/dsp1
Opened /dev/video ('BT878(Hauppauge (bt878))')
Video standard is 'PAL' (25.00 Hz)
Audio unmuted
Filter 'YUYV 4:2:2 w/vertical decimation'
Image format 'YUYV' 352 x 576 granted
24 capture buffers granted
Reading from stdin
Audio compression 44.1 kHz mono at 80 kbits/s (8.8 : 1)
Psychoacoustic threshold table #1
Macroblocks 22 x 18
Video compression 352 x 288, 25.0 frames/s at 3.00 Mbits/s (10.1 : 1)
Motion compensation disabled
Audio compression thread launched
Video compression thread launched
0:39 (14.1 MB), system load 100.0 %,  5.70 % dropped  
Stop at 1011783503.853849


As you can see, I'm using mp1e (CVS version) for grabbing and encoding.

If I save the stream directly to disk, I can use a picture size of
480x576 (yes it is supported by the dvb card) and a bit rate of 6000 
without frames dropped. I think these results are not so bad on my
box (0.33 GHz Celeron). But, direct feeding to ntuxplayer is more
power consuming, as you can see above.

To get these results, I had to use the 0.8.x-branch of the bttv-driver.
My audio source is the bt878 chip (functionality providet by btaudio).
(I had to patch mp1e a little bit, becouse some ioctls are not 
supported by btaudio.)

-- 
Frank