[vdr] Implementing new device into a plugin :

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

Hi,

As I told you before, I'm working on a new class derived from cDevice
(cEm84Device).

My device can decode several audio format (AC3, DTS, PCM) and video
format (MPEG2, MPEG1).
This device is also OSD capable but I'll work on it later.

To create this new class I read the VDR documentation but I have
questions about the following methods :

1) void cDevice::Play( void ) [virtual]
What is the difference between the playModes
pmNone, pmAudioVideo, pmAudioOnly, pmAudioOnlyBlack,
pmExtern_THIS_SHOULD_BE_AVOIDED

2) int cDevice::PlayVideo ( const uchar *Data, int Length ) [virtual]
DOC : "Actually plays the given data block as video. The data must be
part of a PES (Packetized Elementary Stream) which can contain one video
and one audio strem."

  a) I can't figure out which part of VDR is sending me this Packet
  b) Does it mean that I have to demux the packet to get only the video
part
  c) How many frames are passed to this method ? (only one, more ?)

3) int cDevice::PlayAudio ( const uchar *Data, int Length ) [virtual]
DOC : "Plays additional audio streams, like Dolby Digital. A derived
class must call the base class function to make sure data is distributed
to all registered cAudio objects."

  a) Why this method seems different from the PlayVideo one? Does it
mean that a device can only replay video ? 
  b) Same questions as above (PlyaVideo) for the Data sent (Multiple
frames ? Demux needed?)

4) Question about the VDR design :
I understand that the first purpose of VDR was to build an application
based on DVB card but since some people have written plugins like the
streamServer / streamClient, could you explain me why you don't move the
DVB code to a plugin ?

5) As your software is every time less DVB dependant, Here is my last
question :
Are you going to change the VDR design ? Let me explain :
As the VDR software can replay many different video/audio format, don't
you think that i twill be easier if th VDR core handle streams and the
plugins all the input / output method ?
For example : 
It should be interessant to make the following actions at the same time:
Read Data from the "DVB plugin" on the current channel
Write this stream to the HD
Read Data from a file (CD-R or HD)
Send this Data to the matching Demuxer Plugin which will send the chosen
videostream to the display plugin and the chosen audio stream to the
audio hardware

I don't know if you will understand what I mean because of my bad
english but in fact, I think that your software should be cut into to
parts :
 - VDR core : stream handling
 - VDR Plugins : Input, Output elements (Video, Audio, EPG, ...).

I'm not a skilled developper but I think that VDR is not anymore a DVB
only plateform. 

If someone can give me some explanations, they will be appreciated.

Thanks a lot to all the developpers who made this project so powerfull.

Philippe



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