[linux-dvb] Re: Umwandeln

[Marcus O.C. Metzler <mocm@convergence.de>]

Klaus Schmidinger writes:
 > Matthias Queisler wrote:
 > > 
 > > How to convert the vdr Data into MPEG2 or DivX ;-). Which format is it?
 > 
 > The VDR video files (001.vdr, 002.vdr,...) contain the PES data
 > delivered by the DVB-driver, which is supposed to be "MEPG2".
 > 
As a small reminder:
Some information about the different stream types:

1) Elementary stream (ES): 
	is the stream that contains the actual compressed
      	audio and video data, like I, P, B-Frames
       	etc., with respective headers and some
       	other information.

2) Packetized elementary stream (PES): 
	is composed of Packets containing ES data. The packets have
        headers, that specify the respective ES data, like
        0x000001E0 for the first video stream. The header also
        holds the packet length and stuff like the PTS. 

3) Program Stream (PS): 
	mainly contains PES packets with some
        additional packets containing some more
        information for the decoder, like the SCR,
        buffer sizes and mux rates. PSs are used by
        DVDs and distributed .vob files.

4) Transport Stream (TS): 
        is composed of packets that all have the
        same size (188bytes). They all start with 0x47.
        The packets are identified by their PID.
        Some of them contain audio and video data
        in the form of PES packets which are spread
        over many packets of size 188 bytes. Other
        packets contain sections which contain various
        things like the PMT, the PAT or videotext
        data. A TS is meant for transporting data
        over networks. 

5) AV_PES: 
	is the format used by the Siemens (Technotrend) DVB card internally.
        The audio AV_PES packets contain audio PES packets with a
        header that tells you wether there is a PTS in the
        packet. The video packets are video PES packets without the
        PES header (that really means the are ES streams) with a
        header that may contain a PTS. The data originally comes
        from a TS, but has already been processed by the decoder
        and is read from the decoders buffer.

For the dvb drivers (old api) it is possible to choose the output
format when loading the modules. Right now AFAIK vdr uses the PS that comes
from the driver. The new dvb api defines a dvr device (digital video
recorder) that is based on the native DVB format namely TS (thats the
way it is sent over the air). It is very unfortunate that the hardware
manufacturers chose not to implement a direct way to get the TS from
the cardn thats why we got this AV_PES format. Otherwise you would
just record the TS stream and also get all the other nice information
like teletext, EPG etc. in one nicely muxed stream. (If you have a
Haupauge Nova than you can get this)

Marcus

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Dr. Marcus Metzler                             
mocm@netcologne.de                     http://www.metzlerbros.de
mocm@convergence.de                    http://www.convergence.de

Convergence Integrated Media GmbH          
Rosenthaler Str. 51                   
D-10178 Berlin                             
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