[dvblast-devel] DVblast Operation steps

[Georgi Chorbadzhiyski]

On 06.9.2013 г. 01:39, "Gonçalo Azevedo (Gmail)" wrote:
> I was writing a document about this subject and doubt come out.
>
> In the previous messages and with the Block diagram i did, you told me that the DVBlast first Demultiplexes the signal that come form the DBV-T receiver and then Multiplexed again... with the information that you give in the configuration file about PID/SID, Streaming IP's etc.
> So why the dvblast demux and mux again ? what really happens in this process? the packets will suffer changes? what changes? can you help me?

Basically there are two types of packets in the stream. Data packets (audio,
video, subtitles, teletext) and control packets (the so called PSI tables).
dvblast doesn't touch data packets just chooses the right ones based on
the PSI tables. Couple of control tables are rebuild - PAT, PMT, SDT.

You should read about mpeg transport stream to get a better overall
understanding of the structures:

https://en.wikipedia.org/wiki/MPEG_transport_stream
http://wiki.multimedia.cx/index.php?title=MPEG-2_Transport_Stream

dvblast uses biTStream to manipulate (demux and mux) the tables.

http://www.videolan.org/developers/bitstream.html

-- 
Georgi Chorbadzhiyski
http://github.com/gfto
http://georgi.unixsol.org/