Graphic card requirements for transcoding

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lukas23
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Graphic card requirements for transcoding

Postby lukas23 » 02 May 2007 11:19

Hi all,

I want to stream some content from my DVB-T card, transcoding it previously to either MPEG and/or OGG (vorbis&theora).

When I play the content locally in the computer where I have my DVB-T card installed, I can watch and hear everything properly, although I receive several warnings (I've attached them in the next lines)

Code: Select all

#Only 1 example of each warning is displayed, even though I get many more [00000290] main demuxer warning: no access_demux module matched "dvb" [00000291] dvb access warning: CAMInit: opening CAM device failed (No such file or directory) [00000291] dvb access warning: unimplemented query in control libdvbpsi error (PSI decoder): TS discontinuity (received 5, expected 0) for PID 0 libdvbpsi error (PSI decoder): TS discontinuity (received 12, expected 0) for PID 18 libdvbpsi error (PSI decoder): TS discontinuity (received 8, expected 0) for PID 592 [00000294] ts demuxer warning: first packet for pid=547 cc=0xc libdvbpsi error (PSI decoder): TS discontinuity (received 10, expected 0) for PID 560 [00000294] ts demuxer warning: pmt error: pid=557 already defined [00000294] ts demuxer warning: first packet for pid=561 cc=0xf [00000346] main private warning: dts != current_pts (223310) [00000346] main private warning: vout synchro warning: pts != current_date (-40000) [00000342] main audio output warning: PTS is out of range (680921), dropping buffer [00000342] main audio output warning: output date isn't PTS date, requesting resampling (52592) [00000343] main video output warning: late picture skipped (46967)
But the problem comes when I want to stream that content in my internal network. I get this error:

Code: Select all

[00000308] [Media: DVB] main demuxer warning: no access_demux module matched "dvb" [00000309] [Media: DVB] dvb access warning: CAMInit: opening CAM device failed (No such file or directory) [00000309] [Media: DVB] dvb access warning: unimplemented query in control libdvbpsi error (PSI decoder): TS discontinuity (received 15, expected 0) for PID 18 libdvbpsi error (PSI decoder): TS discontinuity (received 7, expected 0) for PID 0 libdvbpsi error (PSI decoder): TS discontinuity (received 12, expected 0) for PID 592 [00000312] [Media: DVB] ts demuxer warning: skipping program (not selected) libdvbpsi error (PSI decoder): TS discontinuity (received 14, expected 0) for PID 544 [00000296] [Media: DVB] main input warning: clock gap, unexpected stream discontinuity
and I don't know what can cause it

Is it possible that a VIA integrated graphic card is not powerful enough to transocode the content?

Any help will be really apreciated.

Jean-Baptiste Kempf
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Postby Jean-Baptiste Kempf » 02 May 2007 13:01

transcoding is NOT done by the graphic card, but CPU
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lukas23
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Postby lukas23 » 02 May 2007 15:03

And having a look at the error, is it possible to get it due to a low processor speed? Or this error is related to something else?

Thanks again

jclark
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Re: Graphic card requirements for transcoding

Postby jclark » 02 May 2007 22:50

Hi all,

I want to stream some content from my DVB-T card, transcoding it previously to either MPEG and/or OGG (vorbis&theora).

When I play the content locally in the computer where I have my DVB-T card installed, I can watch and hear everything properly, although I receive several warnings (I've attached them in the next lines)
I have not had the chance to experiment extensively with VLC, but I have seen cases when one is transcoding, the processor is not able to keep up the 'live video' display on the machine where the transcoding occurs.

This in some sense doesn't have anything to do wtih the 'video' card, but the power of the processor and memory interface to bring in data via some I/O port, manipulate data, then send it out some other I/O port.

Perhaps disabling the realtime display locally would allow the processor to just transcode and distribute to the net, as you seem to want to do...

lukas23
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Postby lukas23 » 04 May 2007 10:34

Problem solved :D

After having a look at several post and browsing almost the hole internet, I started from scratch to check what could be wrong. For some reason that I don't understand, VLC was not able to stream the channel I was able to play locally. As you may know, there's a DVB tool called SCAN that allows you to perfom a frequency scan to chech which are the available channels in your area. It gives you all the params you need to set up a DVB tune properly. I did it and I got 3 parameters for the "programs" field. I just add the 2 I had missed (because the first time I just checked a web page for the program number) and everything worked (with warnings, but worked).

So, at the end, it was as easy as replacing --program 545 with --programs 545,546,515 and start streaming :wink:

Thanks for your help


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