The arguments define the set of streams (all from the same multiplex, or transponder) that are to be recorded at the same time into each file.
Each stream definition must start with a filename, followed by either channel names or pid numbers. Also, you must specify the duration of the stream. Finally, an offset time can be specified that delays the start of the stream (for example, if the start time of the programs to be recorded are staggered).
A file defined by channel name(s) may optionally also contain a language spec and an output spec:
The output spec determines which type of streams are included in the recording. By default, "video" and "audio" tracks are recorded. You can override this by specifying the output spec. For example, if you also want the subtitle track to be recorded, then you need to specify the output includes video, audio, and subtitles. This can be done either by specifying the types in full or by just their initials.
For example, any of the following specs define video, audio, and subtitles:
"audio, video, subtitle" "a, v, s" "avs"
Note that, if the file format explicitly defines the type of streams required, then there is no need to specify an output spec. For example, specifying that the file format is mp3 will ensure that only the audio is recorded.
In a similar fashion, the language spec determines the audio streams to be recorded in the program. Normally, the default audio stream is included in the recorded file. If you want either an alternative audio track, or additional audio tracks, then you use the language spec to define them. The spec consists of a space seperated list of language names. If the spec contains a '+' then the audio streams are added to the default; otherwise the default audio is excluded and only those other audio tracks in the spec are recorded. Note that the specification order is important, audio streams from the language spec are matched with the audio details in the specified order. Once a stream has been skipped there is no back tracking (see the examples below for clarification).
For example, if a channel has the audio details: eng:601 eng:602 fra:603 deu:604 (i.e. 2 English tracks, 1 French track, 1 German) then
Results in the default audio (pid 601) and the next english track (pid 602) recorded
Results in just the french track (pid 603) recorded
Results in the second english (pid 602) and the french track (pid 603) recorded
Results in an error. The english tracks have already been skipped to match the french track, and so will not be matched again.
Note that the output spec overrides the language spec. If the output does not include audio, then the language spec is ignored.
Timeslip recording uses the now/next live EPG information to track the start and end of the program being recorded. This information is transmit by the broadcaster and (hopefully) is a correct reflection of the broadcast of the program. Using this feature should then allow recordings to be adjusted to account for late start of a program (for example, due to extended news or sports events).
To use the feature you MUST specify the event id of the program to be recorded. This information is the same event id that is gathered by the "epg()" function. By default, the timeslip will automatically extend the end of the recording by up to 1 hour (recording stops automatically when the now/next information indicates the real end of the program).
Sets the event id to be 41140
Optionally you can specify a different maximum timeslip time using the 'max_timeslip' argument. Specify the time in minutes (or HH:MM or HH:MM:SS). Note that this has a different effect depending on the timeslip setting (which specifies the program 'edge'):
Sets the maximum timslip time to be 2 hours (i.e. by default, the recording end can be extended by up to 2 hours)
Also, you can set the 'edge' of the program that is to be timeslipped using the timeslip parameter:
Timeslips only the end of the recording. This means that the recording will record for the normal duration, and then check to see if the specified event (event_id) has finished broadcasting. If not, the recording continues until the program finishes OR the maximum timeslip duration has expired.
This is the default.
Timeslips only the start of the recording. This means that the recording will not start until the event begins broadcasting. Once started, the specified duration will be recorded.
Note that this can mean that you miss a few seconds at the start of the program (which is why the default is to just extend the end of the recording).
Performs both start and end recording timeslipping.
Example valid sets of arguments are:
Record channel BBC1 into file f1.mpeg, include subtitles, add second English audio track, record for 1 hour, start recording 10 minutes from now
Record channel BBC2 into file f2.mp3, audio only, record for 30 minutes
Record pids 600 & 601 into file f3.ts, record for 30 minutes
The TSID definition defines the transponder (multiplex) to use. Use this when pids define the streams rather than channel names and the pid value(s) may occur in multiple TSIDs.
If you define default language or output specs, these will be used in all file definitions unless that file definition has it's own output/language spec. For example, if you want all files to include subtitles you can specify it once as the default rather than for every file.
For full details of the DVBT functions, please see Linux::DVB::DVBT: