[vdr] Re: What the best to try HDTV ?

[Reinhard Nissl <rnissl@gmx.de>]

Hi,

jori.hamalainen@teliasonera.com wrote:

> > Meanwhile I've found what's going wrong and started coding a 
> > fix. It seems to me like I can finish it till Sunday, so 
> > anyone who recorded this broadcast should be able to watch it then.
The problem was that Pro7HD splits AC3 frames even across the original (xine's 
demuxer calls them "jumbo") PES packets which didn't happen for all other 
dolby channels so far. Therefore the logic for assembling the original PES 
packets from VDR's 2048 byte packets was simply to cheap to feed the data to 
xine in a way it could properly recognize AC3 frames. The result was a 
discarding allmost all audio frames due to incorrect recognition or wrong 
checksums.

But I was not alone: even a Technisat FTA receiver (not capable of showing a 
HDTV image but capable of playing the sound) couldn't recognize AC3 data and 
show things like bitrate, etc.

> I also tested all HDTV channels on yesterday (Thursday).
>
> HD1 - "Venus bikini model" -stuff seemed to work ok, but time to time 
> (maybe 5 times in 30 minute show) picture started stuttering (like 5 fps) 
> and I lost sound. Once it cured by itself but on other times fix was 
> changing channel to other channel than HD1 and back. Simultaneously I
> recorded the channel. And used Xine's deinterlacer.
Are you shure that this channel is HD1 (former Euro1080)? I think that this 
one is Astra HD as I have the same problems here on this channel.

I think the problem is that they broadcast "sniplets" of different stream 
which all have no continuous presentation time stamps (PTS). And whenever xine 
detects a discontinuity in PTS it drops a few frames while syncing to the new 
PTS rage and goes on in the stream which will finally lead to a buffer underrun.

You'll also get the same behaviour with xine's DVB support although it may 
take longer before the buffer underruns (= playback stops and buffering takes 
place) as xine uses a larger buffer.

> Pro7HD - Had picture (Simpsons, Talk Talk) but newer got any sound (pid or
> demux problem?). Pro7 AC-3 channel had sound on same show that came from
> HD-channel.
See my first paragraph.

> Astra HD didn't send any signal??
I assume you mean HD1 (former Euro1080). I'm not shure whether they are on air 
24x7 but maybe you just watched at a time when they broadcasted a encrypted 
stream.

> Pro7HD & Astra HD PID's were from this mailinglist from yesterday. It is
Just to make shure (Pro7HD is off air meanwhile):

Euro1080:12168:vC34:S19.2E:27500:308:256=eng:0:0:21100:0:0:0
ASTRA HD:12441:vC34:S19.2E:27500:133+80:134=eng:0:0:29700:1:1102:0

Bye.
--
Dipl.-Inform. (FH) Reinhard Nissl
mailto:rnissl@gmx.de