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
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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.
 

alerino

Well-Known Member
Joined
Aug 11, 2007
Messages
3,200
Lomaxx said:
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.

have you tried the new Panplayer (modified mplayer)?

i have an old usb tv card, but can't get it to work, could you help me out? Kernel recognizes it as em28xx chipset but no driver support.
 
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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.
 

alerino

Well-Known Member
Joined
Aug 11, 2007
Messages
3,200
found some info here => http://linuxtv.org/wiki/index.php/Em28xx_devices


that's what i get from dmesg and lsusb outputs

pandora dmesg
Code:
[ 3862.612548] usb 1-2: new high speed USB device using ehci-omap and address 6
[ 3862.769531] usb 1-2: configuration #1 chosen from 1 choice
[ 3862.786590] usb 1-2: New USB device found, idVendor=eb1a, idProduct=2800
[ 3862.793395] usb 1-2: New USB device strings: Mfr=0, Product=0, SerialNumber=0

pandora lsusb
Code:
Bus 001 Device 001: ID 1d6b:0002 Linux Foundation 2.0 root hub
Bus 001 Device 006: ID eb1a:2800 eMPIA Technology, Inc. Terratec Cinergy 200

ubuntu box dmesg

Code:
[ 9784.710049] usb 1-2: new high speed USB device using ehci_hcd and address 6
[ 9784.863478] usb 1-2: configuration #1 chosen from 1 choice
[ 9784.956609] em28xx: New device @ 480 Mbps (eb1a:2800, interface 0, class 0)
[ 9784.956750] em28xx #0: em28xx chip ID = 1
[ 9785.172541] em28xx #0: board has no eeprom
[ 9785.292539] em28xx #0: preparing read at i2c address 0x60 failed (error=-19)
[ 9785.412544] em28xx #0: Identified as Unknown EM2800 video grabber (card=0)
[ 9800.800057] em28xx #0: Your board has no unique USB ID and thus need a hint to be detected.
[ 9800.800062] em28xx #0: You may try to use card=<n> insmod option to workaround that.
[ 9800.800064] em28xx #0: Please send an email with this log to:
[ 9800.800065] em28xx #0: 	V4L Mailing List <linux-media@vger.kernel.org>
[ 9800.800066] em28xx #0: Board eeprom hash is 0x00000000
[ 9800.800068] em28xx #0: Board i2c devicelist hash is 0x1b800080
[ 9800.800069] em28xx #0: Here is a list of valid choices for the card=<n> insmod option:


[ 9801.310586] em28xx #0: Config register raw data: 0xd5
[ 9801.510043] em28xx #0: AC97 command still being executed: not handled properly!
[ 9801.510047] em28xx #0: AC97 chip type couldn't be determined
[ 9801.510048] em28xx #0: Unknown AC97 audio processor detected!
[ 9804.610058] em28xx #0: v4l2 driver version 0.1.2
[ 9808.530149] em28xx #0: V4L2 video device registered as /dev/video1
[ 9808.530188] usbcore: registered new interface driver em28xx
[ 9808.530191] em28xx driver loaded
[ 9808.578463] em28xx-audio.c: probing for em28x1 non standard usbaudio
[ 9808.578466] em28xx-audio.c: Copyright (C) 2006 Markus Rechberger
[ 9808.578793] Em28xx: Initialized (Em28xx Audio Extension) extension
[ 9815.660056] Error while configuring em28xx mixer
 
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