On Friday 15 Jun 2007, Jonathan McDowell wrote:
On 12/06/07, Alex Stansfield mailing-lists@jinkies.net wrote:
If anyone knows any more about how the system works or has the DTG specification (can't see it on their website) please let me know.
MythTV seems to have added support:
Hmmm. I worked out the scheme using dvbsnoop last night, then decided it couldn't possibly be so simple. Seems I was right after all...
The data is transmitted in the EIT. Each entry has zero, 1 or 2 Content Identifier Descriptors, with table ID 0x76. The format of this descriptor seems to be:
Descriptor tag, 8 bits (always 0x76) Descriptor length, 8 bits crid_type, 6 bits crid_location, 2 bits (always seems to be 00) crid_len, 8 bits crid_data, crid_len bytes.
If crid_type = 0x31 then crid_data contains the program ID, which I think is supposed to uniquely identify the programme irrespective of repeats etc.
If crid_type = 0x32 then crid_data contains the series ID, which should be the same across all episodes of a series. The series ID is sometimes omitted if the programme is a one-off.
I'm not sure just how unique these identifiers are supposed to be; the series identifiers are generally 5-digit numbers or 6-character alpha strings preceded by "/", while the program ID seems to have the episode number appended.
On Sandy Heath I only see this data on the BBC, "4" and sky channels, not ITV.
Dave