>On Thu, May 25, 2006, christophpfister@xxxxxxxxxxx wrote:
>> Arrrrgh, twice the same error :(
>>
>> [snip]
>> >>If the transmitter broadcasts MIS, I have to set a stream_id
>> >>(otherwise I'd get a garbage mix of multiple TS, right?).
>> >>Do I then have to set the sismis to DVBFE_SISMIS_MULTIPLE
>> >>(because it's MIS) or DVBFE_SISMIS_SINGLE (because I want
>> >>to filter out just one of them)?
>> [snip]
>> >sismis and stream_id are only used in backward compatible mode.
>> >In the mis mode both hp and lp streams are received, whereas in sis mode
>> >stream_id is used to select hp or lp stream.
>> [snip]
>>
>> sismis and stream_id are only used in backward compatible mode.
>> In the sis mode there is only one stream to receive, whereas in mis mode
>> stream_id is used to select hp or lp stream.
>>
>> Sorry for any confusion.
>
>I was just about to complain ;-)
>
>
>My question was regarding the semantics of and/or naming
>of the sismis flag. I'm sorry for the unclear wording,
>I'll try again:
>
>- SIS/MIS is part of baseband signalling (BBHEADER): My understanding
> is that the demod can receive the BBHEADER without prior knowledge
> if it is SIS or MIS. Thus you don't have to tell it about that.
>
>- However, if it is MIS: You have to enable the stream-id filter in
> the demod and set a stream_id (ISI), otherwise you'd get either
> garbage (two or more TS mixed together) or nothing (depending
> on how demod hw/fw handles this error)
>
>- Similarly, if it is SIS, you have to disable the stream-id
> filter because you don't know the stream_id to filter on
> (unless the demod hw/fw does disregard the filter anyway if
> it sees the stream is SIS)
>
>Consequently, I would rename "enum dvbfe_sismis_flag sismis"
>to a boolean "enable_stream_id_filter". Because this
>type and name would reflect what it actually does.
>
>So, not a functional change, the drivers would use
>enable_stream_id_filter in exactly the same way as
>sismis, but it is easier to understand how to use
>the API.
>
>Provided that my understanding of the matter is correct, of course.
>
>
>Johannes
Yes, you're understanding is correct.
I have a nice idea about this (because sismis is only used at bc mode).
What do you think of the following?
[snip]
+/*
+ * Optional Backwards Compatible Mode
+ * NOTE: Applies to DVB-S2 only
+ */
+enum dvbfe_obc_mode {
+ DVBFE_OBC_IGNORE = (0 << 0),
+ DVBFE_OBC_OFF = (1 << 0),
+ DVBFE_OBC_SIS = (1 << 1),
+ DVBFE_OBC_MIS = (1 << 2)
+};
[snip]
+/*
+ * DVB-S2 parameters
+ */
+struct dvbs2_params {
+ __u32 symbol_rate;
+
+ enum dvbfe_modulation modulation;
+ enum dvbfe_fec fec;
+ enum dvbfe_obc_mode obc_mode;
+ enum dvbfe_rolloff rolloff;
+ __u8 stream_id; /* only used if obc_mode == DVBFE_OBC_MIS */
+
+ __u8 pad[32];
+};
Christoph
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