[linux-dvb] [PATCH] Multi protocol support

Manu Abraham abraham.manu at gmail.com
Wed Apr 12 16:48:36 CEST 2006


Hello Andreas,

Andreas Oberritter wrote:
>> +typedef enum {
>> +       DMX_PROTO_DVB_S,
>> +       DMX_PROTO_DVB_C,
>> +       DMX_PROTO_DVB_T,
>> +       DMX_PROTO_DSS,
>> +       DMX_PROTO_ATSC,
>> +       DMX_PROTO_DVB_S2
>> +} dmx_protocol_t;
>>     
>
> Why should a demux care how the TS was delivered? All DVB variants and
> ATSC use MPEG-2 TS, right? I don't know about DSS though.
>
>   

Some protocols need different SYNC words , stream lengths etc for the 
demuxer to work (DSS and DVB-S2 differ from DVB-S/C/T/ATSC) DSS has a 
different SYNC word and a different stream lengths, but S2 has more 
modes of operation which again needs this.

So there are 3 different categories
(1) DVB--> DVB-S/C/T/ATSC
(2) DSS
(3) DVB-S2 --> multiple modes


>> +typedef enum {
>> +       DMX_TRANSPORT,
>> +       DMX_GENERIC_PACKET,
>> +       DMX_GENERIC_CONTINUOUS,
>> +       DMX_RESERVED
>> +} dmx_bbheader_t;
>>     
>
> What is this data type good for? It seems to be unused.
>   

The stream can be a TS (normally) but can be other types as well. This 
one will need quite a bit of work, but this just the start ..

>> +typedef enum {
>> +       FE_PROTO_DVB_S,
>> +       FE_PROTO_DVB_C,
>> +       FE_PROTO_DVB_T,
>> +       FE_PROTO_DSS,
>> +       FE_PROTO_ATSC,
>> +       FE_PROTO_DVB_S2
>> +} fe_protocol_t;
>>     
>
> I don't think that protocol is a proper name. In DVB terms S, C and T
> are called delivery systems.
>   


What would be your suggestion .. ? FE_SYS_XXXX. Or any other suggestion ?


>> +typedef enum {
>> +       FE_TRANSPORT,
>> +       FE_GENERIC_PACKET,
>> +       FE_GENERIC_CONTINUOUS,
>> +       FE_RESERVED
>> +} fe_bbheader_t;
>>     
>
> See dmx_bbheader_t.
>
> IIRC it was discouraged to introduce new typedefs.
>
> How does an program know which delivery systems are supported by a frontend?
>   

Any suggestions .. ?
we need to know the delivery system as well the stream type from the 
frontend and the demux
at this point for some new devices we will need to create an adapter 
device too, since the bridge device also needs to know about this 
(aligned transfers etc), which IMHO, should be handled in the adapter 
device only as it doesn't fit into the frontend or the demux.


Regards,
Manu




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