PID - TS Packet identifier
Elementary streams (video, audio) and information tables are packed to the TS-packets. Each packet has unique identifier - PID.
PID value should be in range from 0 to 8191. Range from 0 to 31 and 8191 preallocated and shouldn't used for elementary streams. For elementary streams possible to use any PID in range from 32 to 8190.
How to find PID values in the stream?
- With VLC player. Play the stream, then open Tools - Media Information - Codec. The "Original ID" field contains PID value
- With Astra analyzer. Launch in console:
astra --analyze "stream address"
CBR/VBR - Bitrate
Stream bitrate has two types:
- VBR - variable bitrate, depends of the stream compression ratio
- CBR - constant bitrate, this is VBR stream stuffed with NULL-TS packets NULL-TS packets have constant PID - 8191 and don't have payload, only zeros.
To generate CBR streams in Astra append the cbr option into the output address. Value should be in Kbit/s. For example:
Note: the "no_sync" option disables CBR
For versions below 5.63 - the CBR option must be used in conjunction with the "sync" option"
If stream bitrate higher than "cbr" value, then stream passed as is. Option works only for UDP-output. For any other formats no reason to use CBR.