[vdr] Cutting problems?

[Wolfgang Fritz <wolfgang.fritz@gmx.net>]

Hello,

If a replay a cutted recording, I often see short video distortions at 
the cuts, mostly block artefacts. This happens with direct replay on the 
DVB card and also when replaying the .vdr file on the PC with mplayer.

If I convert the recording to DVD format with the vdr2dvd.pl script, the 
demuxer ds.jar gives messages like this:

use config file /usr/local/etc/ds.ini ...
V0.61h (21.01.2003)

=> working with collection 0
=> write output files to /home/wofritz/dvd/tmp/

=> File 0:  /home/wofritz/dvd/tmp/vdralltemp.vdr  (26770639 bytes)
=> File is a Video/Audio/TTX PES
-> found PES-ID 0xE7 (MPEG Video)emp.vdr
-> found PES-ID 0xC0 (MPEG Audio)
-> video basics: 720*576 @ 25fps @ 0.6735 (4:3) @ 15000000bps, vbvBuffer 112
cut detected @ GOP#0 / new Timecode 00:00:00.000
cut detected @ GOP#17 / new Timecode 00:00:08.120
cut detected @ GOP#31 / new Timecode 00:00:14.800
cut detected @ GOP#49 / new Timecode 00:00:23.400
cut detected @ GOP#120 / new Timecode 00:00:57.440
video: fr/ct/1p/cg/og/dg  1591/5/0/133/0/0
videolength: 1591f @ 00:01:03.640
avg. nom. bitrate 3129330bps (min/max: 1849200/5693600)
set first sequence_header bitrate to 5693600bps
===> new File: /home/wofritz/dvd/tmp/vdralltemp.mpv
--> MPEG Audio (0xC0)
Audio PTS: first packet 01:34:53.934, last packet 01:36:17.334
Video PTS: start 1.GOP 01:34:54.381, end last GOP 01:36:17.381
-> adjusting audio at video-timeline
=> src_audio: MPEG-1,Layer2,48kHz,stereo,192kbps,CRC @ 00:00:00.000
-> 18 frame(s) (432ms) inserted @ 00:00:07.680.mp
-> 18 frame(s) (432ms) inserted @ 00:00:14.376.mp
-> 18 frame(s) (432ms) inserted @ 00:00:22.968.mp
-> 14 frame(s) (336ms) inserted @ 00:00:57.096.mp
audio frames: wri/pre/skip/ins/add 2652/0/0/68/0  @ 00:01:03.648 done..
===> new File: /home/wofritz/dvd/tmp/vdralltemp.mp2

I can understand that ds.jar detects the cuts by the jumps in the 
timecode, but what I do not understand is that it has to insert audio 
frames at the cuts for several hundred milliseconds to maintain A/V sync.

If I replay the resulting DVD image file with mplayer, I can notice the 
short pauses in the audio at the cuts, but the video distortions are gone.

It seems to me as if video and audio are cutted at different times and 
some audio is "lost" at the cuts.

Has anybody seen these effects too?

Wolfgang




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