Small Update About Dvb-T On Pandora


lomaxx

Active Member
Joined
Sep 22, 2008
Messages
747
I gave DVB-T on my Pandora another try and i managed to get a somewhat pleasing result without overclocking. So far i only cropped the image to 800x480 (DVB-video is 704x576) as the software-scaler is far too slow. So there is a small part missing, but so far that didn't disturb too much and the framerate offers a smooth video-output. Audio is out of sync for a very few (maybe 5) seconds in the beginning, but after that is fine.

Hardware used: An old DVB-T-USB-stick named "Yakumo Quickstick Basic DVB-T" (not produced anymore, company does not exist anymore)

As player i used the modfied mplayer included in panplayer with the following parameters:

Code:
mplayer -vo xv -ao sdl -ac mad -framedrop -vf crop=800:480 dvb://<channelname_configured_in_channels.conf>

I am far from being an mplayer- or video-expert, but here is what i noticed about each parameter:

"-vo xv" is not really necessary. I just tried both "xv" and "x11" video-outputs since they scale in different ways in fullscreen-mode
"-ao sdl" brings a great performance gain AFAIK
"-ac mad" - Without this audio was not playing when using panplayers mplayer.
"-framedrop" actually also works without, but I still use
"-vf crop=800:480" crops the image. I also tried "scale", but as already mentioned this is by far too slow.

If someone knows more about what might improve the output, please let me know. Especially a faster scaling-method would be appreciated.
And feel free to ask for more details if you need them.
 

WizardStan

Mega GP Mania
Joined
May 24, 2008
Messages
16,733
Wasn't really sure this belonged in the news section (although it is good to hear) so I moved it to general talk.
 

lomaxx

Active Member
Joined
Sep 22, 2008
Messages
747
I just noticed that the cropping/scaling-issue is just one for DVB-PAL-users as NTSC seems to have a height of 480 pixels.

@Alerino: If i saw it right, then your tv-box is not an DVB (digital video broadcast) one, but an analog one. Isn't it? I will try to help you, but i myself am always having problems with stuff like this. ;) I simply got too few background-knowledge and easily get confused. And i try around a lot, which i can't do without having the hardware. Well let's see what i can find out.

According to this site your Transcend TV-box is "bases on EMPIA Technology EM2800 chip. The signal receiving selector is TVision TVF9531-B/DF, while the ADC is Philips SAA7113(7114)H." Maybe this information will help us to get it running.

Here is some more information about this chip, but I'm not sure if there are some helpful bits in there. Maybe the v4l-dvb-wiki is the better place to start.

I just did a "opkg list-installed | grep v4l" on the pandora as root. I can't remember if this is installed by default or if i installed it myself as it's been a while that i started doing tests with my dvb-stick. I can't even say if we really need it, but i guess we do. Anyway, i had three results: "kernel-module-v4l1-compat", "kernel-module-v4l2-common" and "kernel-module-v4l2-int-device".

So far for now. If i find more useful information, then i will report back.
 
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