On 16/02/07 07:02:10, timecop wrote: > >Thanks for Your reply. After reading some docs about mpeg-TS I still > >have > >difficulties to realize the effects of loosing TS packets to the > >macroblocks > >(16x16 pixels) of the mpeg-2 video. Is there at least one full macroblock > >in a > >TS packet? > > I never dealt with mpeg2 on the "macroblock" level in TS, but as you > probably read, a single mpeg "frame" will span several TS packets. > > >To put my question in other words: > >If my dvb-t device doesn't get the full stream will this always lead > >to > >missing macroblocks or can it yield less obvious loss of quality > >(like > >unsharpness)? > > Losing a single TS packet, in HD, and especially in SD broadcast will > not lead to "unsharpness", you will receive visible ruined image > artifacts, which usually look like inverted/green/or otherwise random > stream of blocks after the missed packet, as mpeg decoder resyncs to > try to decode. Thanks a lot. This makes it clear. > > >Does the type of device influence the qualtity of the recieved stream? > >(Why do > >devices differ in prices so much?) > The only difference would be a more sensitive tuner. > If your C/N ratio is high, BER is low/or zero, and no continuity > errors in the stream, you're getting everything at full quality. This is very valuable to know. Sadly I couldn't find any info on this in the net. What would You recon is ment with "signal strength" and "signal quality" in the M$ windows dvb-t programme? Would it be SIG and SNR as reportet by dvbsnoop or tzap? What do the other values discribe? SNR is never changing although it is reported. Here is some output of usbsnoop and tzap: tzap ard using '/dev/dvb/adapter0/frontend0' and '/dev/dvb/adapter0/demux0' reading channels from file '/home/lynx/.tzap/channels.conf' tuning to 191500000 Hz video pid 0x0201, audio pid 0x0202 status 03 | signal 8675 | snr 0000 | ber 001fffff | unc 00000000 | status 1f | signal 8435 | snr 0000 | ber 00000000 | unc 00000013 | FE_HAS_LOCK status 1f | signal 8455 | snr 0000 | ber 00000000 | unc 00000000 | FE_HAS_LOCK status 1f | signal 844e | snr 0000 | ber 00000000 | unc 00000000 | FE_HAS_LOCK dvbsnoop -s signal -pd 9 -n 9 -timeout 1000 dvbsnoop V1.4.00 -- http://dvbsnoop.sourceforge.net/ DEMUX : /dev/dvb/adapter0/demux0 DVR : /dev/dvb/adapter0/dvr0 FRONTEND: /dev/dvb/adapter0/frontend0 --------------------------------------------------------- Transponder/Frequency signal strength statistics... max cycle count: 9 Capabilities: BER: 1 SNR: 1 SIG: 1 STAT: 1 UBLK: 1 --------------------------------------------------------- cycle: 1 d_time: 0.001 s Sig: 33912 SNR: 0 BER: 0 UBLK: 0 Stat: 0x1f [SIG CARR VIT SYNC LOCK ] cycle: 2 d_time: 1.017 s Sig: 34416 SNR: 0 BER: 0 UBLK: 0 Stat: 0x1f [SIG CARR VIT SYNC LOCK ] cycle: 3 d_time: 1.020 s Sig: 33891 SNR: 0 BER: 0 UBLK: 0 Stat: 0x1f [SIG CARR VIT SYNC LOCK ] cycle: 4 d_time: 1.020 s Sig: 33933 SNR: 0 BER: 0 UBLK: 0 Stat: 0x1f [SIG CARR VIT SYNC LOCK ] cycle: 5 d_time: 1.020 s Sig: 33933 SNR: 0 BER: 0 UBLK: 0 Stat: 0x1f [SIG CARR VIT SYNC LOCK ] cycle: 6 d_time: 1.016 s Sig: 33945 SNR: 0 BER: 0 UBLK: 0 Stat: 0x1f [SIG CARR VIT SYNC LOCK ] cycle: 7 d_time: 1.016 s Sig: 33959 SNR: 0 BER: 0 UBLK: 0 Stat: 0x1f [SIG CARR VIT SYNC LOCK ] cycle: 8 d_time: 1.016 s Sig: 33956 SNR: 0 BER: 0 UBLK: 0 Stat: 0x1f [SIG CARR VIT SYNC LOCK ] cycle: 9 d_time: 1.016 s Sig: 33939 SNR: 0 BER: 0 UBLK: 0 Stat: 0x1f [SIG CARR VIT SYNC LOCK ] Regards, Lynx _______________________________________________ linux-dvb mailing list linux-dvb@xxxxxxxxxxx http://www.linuxtv.org/cgi-bin/mailman/listinfo/linux-dvb
