[linux-dvb] The origin of the pts ?

[Peter Maersk-Moller <peter@maersk-moller.net>]

Hi

Every now and then I seem to encounter PTS-values which seems to
be less than their predecessor. As far as I remember, then the
MPEG-2 TS is recreated by TT budget/Full card thus creating
some of the header data on the-fly instead of just relaying data
exact as it was recived. Is this correct ? If yes, is the PTS
then recreated by the DVB card or is it just relayed as-is ?

The reason I'm asking is that every now and then I seem to get
a PTS of a frame belonging in the past. See the log below, where I
receive data with a TT Budget (NOVA-s), broadcast with dvbstream,
receive and decode with libmpeg2 (in mp4live).

As you can see, there may be minutes between.

Assuming libmpeg2 is decoding correct (and that I use libmpeg2
correct, could the *PTS fro mthe past* be caused by loosing data
every now and then on tha satellite down-link ?

Kind regards

--PMM


11:28:06.255-mp4live-3: Now audio can begin : video start pts 2572968808 - audio pts 2572969527  =  -719 (-7ms)
11:40:39.744-mp4live-3: Video pts problem. Current pts < previous pts
11:40:39.744-mp4live-3:  - previous pts = 2640818008
11:40:39.744-mp4live-3:  - current pts  = 2640810808
11:40:39.744-mp4live-3:  - delta pts    = -7200 (-80 ms)
11:40:39.744-mp4live-3:  - I will skip the frame
11:40:39.744-mp4live-3: Video pts problem. Current pts < previous pts
11:40:39.744-mp4live-3:  - previous pts = 2640818008
11:40:39.744-mp4live-3:  - current pts  = 2640814408
11:40:39.744-mp4live-3:  - delta pts    = -3600 (-40 ms)
11:40:39.744-mp4live-3:  - I will skip the frame
11:43:23.044-mp4live-3: Video pts problem. Current pts < previous pts
11:43:23.045-mp4live-3:  - previous pts = 2655452008
11:43:23.045-mp4live-3:  - current pts  = 2655444808
11:43:23.045-mp4live-3:  - delta pts    = -7200 (-80 ms)
11:43:23.045-mp4live-3:  - I will skip the frame
11:43:23.045-mp4live-3: Video pts problem. Current pts < previous pts
11:43:23.045-mp4live-3:  - previous pts = 2655452008
11:43:23.045-mp4live-3:  - current pts  = 2655448408
11:43:23.045-mp4live-3:  - delta pts    = -3600 (-40 ms)
11:43:23.045-mp4live-3:  - I will skip the frame
12:05:13.765-mp4live-3: Video pts problem. Current pts < previous pts
12:05:13.765-mp4live-3:  - previous pts = 2773496008
12:05:13.765-mp4live-3:  - current pts  = 2773492408
12:05:13.765-mp4live-3:  - delta pts    = -3600 (-40 ms)
12:05:13.765-mp4live-3:  - I will skip the frame
12:05:18.293-mp4live-3: Video pts problem. Current pts < previous pts
12:05:18.293-mp4live-3:  - previous pts = 2773917208
12:05:18.294-mp4live-3:  - current pts  = 2773913608
12:05:18.294-mp4live-3:  - delta pts    = -3600 (-40 ms)
12:05:18.294-mp4live-3:  - I will skip the frame
12:14:44.577-mp4live-3: Video pts problem. Current pts < previous pts
12:14:44.578-mp4live-3:  - previous pts = 2824785208
12:14:44.578-mp4live-3:  - current pts  = 2824778008
12:14:44.578-mp4live-3:  - delta pts    = -7200 (-80 ms)
12:14:44.578-mp4live-3:  - I will skip the frame
12:14:44.578-mp4live-3: Video pts problem. Current pts < previous pts
12:14:44.578-mp4live-3:  - previous pts = 2824785208
12:14:44.578-mp4live-3:  - current pts  = 2824781608
12:14:44.578-mp4live-3:  - delta pts    = -3600 (-40 ms)
12:14:44.578-mp4live-3:  - I will skip the frame
12:24:40.810-mp4live-3: Video pts problem. Current pts < previous pts
12:24:40.810-mp4live-3:  - previous pts = 2878540408
12:24:40.810-mp4live-3:  - current pts  = 2878536808
12:24:40.810-mp4live-3:  - delta pts    = -3600 (-40 ms)
12:24:40.810-mp4live-3:  - I will skip the frame