[vdr] RE : AW: About the VDR SoftDevice Plugin

["Philippe Gaultier" <philippe@accuitee.com>]

> When the plugin runs (and doesn't crash due other issues ;-) it decodes
> all
> frames, so I think the code should be (more or less) correct. Maybe you
> can
> dump the packets passed to avcodec in a file and try to replay with an
> other
> software.
> What hardware do you have, maybe you set up replay type wrong. (e.g.
> replay audio AND video. If there's no audio the device can't sync or so)
> 
> Roland

Ok thanks for the information.

I'm working on the SigmaDesign Xcard, it embeds an MPEG1/2/4 decoder.
I wrote the OSD part (finished) and I'm now working on the MPEG2 part.

I used your code "as is" (just stripped out all the synchro and avcodec
stuff) and everything is all right except LiveTV.

The problem during the LiveTV playback is that the decoder only present
IFRAMES. 
The only "work around" I found is to play a recording and then to switch
back to the channel I want to see (sometimes, it works and LiveTV is
perfect).

Some questions now :

- My mpeg decoder needs an Elementary Stream (m2v)
- VDR delivers PES.
- I'm not in trouble with synchro because I only want to display the video
over my Device.

1) as I do not fully understand your code, could you tell me if you strip
off all the PES header and if the following code could do the same job :

-----------8<-----------
while(<I have some data to demux and extract in the buffer>)
{
  if((Data[pes+0]==0x00)&&(Data[pes+1]==0x00)&&(Data[pes+2]==0x01))
  {
    es_len=Data[pes+4]*256+Data[pes+5]+6-(9+Data[pes+8]);
    es_start=pes_start+9+Data[pes+8];
    // additional code to extract PTS and DTS
    if((Data[pes+6]&0xC0)==0x80))
    {
	// we have an MPEG2 bitstream
	if ((Data[pes+3]>=0xE0)&&(Data[pes+3]<=0xEF))
        myDevice->PlayVideo(inbuf_ptr+es_start,es_len);
      else if ((Data[pes+3]>=0xC0)&&(Data[pes+3]<=0xCF))
        myDevice->PlayAudio(inbuf_ptr+es_start,es_len);
    }
  }
  // jump to the next Pes
  pes +=Data[pes+4]*256+Data[pes+5]+6;
}
-----------8<-----------

2) Do you now if the MPEG Elementary Stream contains PTS and DTS ?
2') Do you know where I can find datasheets about MPEG2 Elementary Streams ?

3) Why did you add a ringBuffer for the video part in SoftDevice 0.0.4?


Thank you 

Philippe


PES Reminder
-----------8<-----------
PES header :
Byte -> Value
  00 -> 0x00
  01 -> 0x00
  02 -> 0x01
  03 -> 0xE0 <-> 0xEF
  04 -> LenHi
  05 -> LenLow Len = buf[04]*256+ buf[05]
  06 -> buf[06]&0xC0 == 0x80 -> Mpeg2
    07 -> Flags PTS|DTS|ESCR|ESRATE|DSM|COPY|CRC|EXTENSION
    08 -> Optional Header Length -> Header = buf[08]+9
.....
.....
-----------8<-----------




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