[linux-dvb] Re: tech questions

[Andreas Schultz <andreas@aschultz.net>]

Hi,

This all sounds a bit like the problem i got with DVD playback. I tried 
to insert LPCM frames with timestamps copied from the original AC3 
frame, the result was a total hung system that could only be recovered 
by a hard reset (i don't have a keyboard and monitor attached to this 
system).
Playing video only (not inserting the audio frames) worked for me, but i 
only tested it for very brief periods. Also only every 15th or so video 
frame from DVD has a PTS.
Others reported that the same code that crashed my system work for them 
(no lookup) but produces different results (major video distortions)

All this makes we wonder if we got us here an hardware (card revision) 
related problem.

Have fun

    Andreas

Arpi wrote:

> Hi,
> 
> 
>>Arpi writes:
>> > Hi,
>> > Ok. My hottest problem now:
>> > I'm trying to playback video-only PS/PES stream (0x1E0 packets only, all
>> > packets has PTS timestamp), but after some time (10 sec .. 30 min, depending
>> > on packet size and bitrate) picture hangs (like still image) and driver eats
>> > data very fast from that points (doesn't block until frames are played).
>> > 
>> > I'm using the test_av.c sample program to play back PES streams generated by
>> > mplayer.
>>
>>Did you switch off synching?
>>
> Tried both: true and false for AVSync. Nothing changed.
> 
> 
>> > I think the main problem is not having audio packets, while card/driver
>> > expects them.
>> > If I send a dummy audio packet (0x1C0 packet, with 4 0xFF bytes in it)
>> > then playback immediately hangs, same effect as I got after some time
>> > when sending only video packets.
>> > 
>> > So, my question: is it a driver bug, a driver limitation (can't play
>> > video-only stuff) or I just should use different ioctls?
>> > 
>>
>>For me 
>>cat <filename> | pes2vid| ntuxplayer -o 
>>
> Ok, I'll check ntuxplayer sources... (I couldn't get it compile, so
> didn't tried yet)
> Does ntuxplayer uses different method for playback than test_av.c ?
> 
> 
>>works fine. I have only tried playing a few minutes though. pes2vid
>>filters the video PES and feeds them to stdout.
>>What is the size of your video PES?
>>
> What do you mean?
> Total file size is 480mb, packet size depends on frames, usually around
> 2-40kb / packet, PES header is always 4 (id) + 2 (size) + 5 (pts) bytes.
> 
> I didn't used 0x1BA or other extra packets/headers in the file, only 0x1E0.
> It isn't file specific, tried several streams, from VCD, DVD, DVB (.vdr) etc.
> 
> If limiting packet size (so using PS instead of PES) to 32k or 2048 bytes,
> I got shorter playback time, hangup comes earlier.
> Without limiting packet size (real PES), got about 20-30 mins of playback
> before hang.

> 
> 
> A'rpi / Astral & ESP-team
> 
> --
> mailto:arpi@thot.banki.hu
> http://esp-team.scene.hu
> 
> 
> 





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