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[linux-dvb] Re: Reconstruct PAT/PMT tables from TS?
Josef Wolf wrote:
> I'm trying to reconstruct PAT/PMT/NIT packets from the TS. I have read
> through ISO-13818, ETSI/EN-300468, ETSI/ETR-211, ETSI/ETR-162 and a lot
> of material I found on google (including some threads on this list).
> But I am still pretty much confused. The informations seem to be
> both, incomplete and contradictory. Here is what I think I have found
> out that far:
> 1. TS packets that belong to a specific PID can transport only one table.
wrong; use table_id
> 2. A table can be constructed from multiple sections.
> 3. Sections can have varying size.
> 4. Sections are sent in no particular order.
well, en300468 "recommends" ascending order (note that EIT is special)
> 5. Sections withhin a table can be replaced independently.
wrong; when a table changes the version number of all sections is incremented;
it is invalid to assemble a table from sections with different version
> 6. Section start is marked with payload_unit_start_indicator in the TS
> 7. Once a section is started, TS packets with the same PID transport
> consecutive parts of the section as long as payload_unit_start_indicator
> is zero.
yes (there is also the possibility that one TS contains multiple short
sections, or the last part of one section and the next section)
> 8. Only the last part of a section can contain an adoption field.
sections contain no adaptation field, TS packets do;
every TS packet can potentially contain one
There is plenty of source out there that implements this. You might
want to read some of it.
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