All posts by John Pilkington
Below are all of John Pilkington's postings, with the most recent are at the bottom of the page.
This is MythTV 0.26-fixes under Fedora 17 (Linux), so I can't relate directly to experience under Windows. I posted because people were concluding that something had changed but didn't know what. This is a real change, I don't see any causal link to the PSB1 retune, and no-one else on the MythTV lists has reported seeing it. My recordings are fine, but I had to modify the part of my editing script that selects the streams I want to keep: select "mpeg2video (Main)" instead of "Video". I don't think many people regularly do this sort of edit.
Does MCE have an "mpeg2video (Main)" codec?
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My Panasonic TV, and MythTV, have no problem with PSB2. My editing script looked for streams recognised as "Video" by ffmpeg, and suddenly found 4 in individual channels of PSB2. Now it looks for "mpeg2video (Main)", finds just one, and works again.
I asked on the MythTV list if any other transmitters had this. Only one response so far. Winter Hill Chs 4 and 5 DO NOT show multiple Video streams with ffmpeg. I suspect a misconfiguration of the PSB2 feed for Waltham.
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I have added before-and-after extracts from my logs from the ProjectX demuxer to the thread on MythTV-users that I quoted on 20 June. They may help. Both recordings from Waltham, Channel 4.
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As further confirmation of what I've said earlier, I've just used the VLC 'Codec info' tool to examine a recording of 'Ennerdale', ITV1 from Waltham, made a few minutes ago. I can't copy-and-paste it, but that shows 4 video streams too. Only the first stream has values for Resolution, Frame rate and Decoded format.
Video IDs are 514, 2051, 2251, 2252
The Video 'Track selector' shows 4 tracks, all of which play identically.
This seems to be specific to the PSB2 mux from Waltham, and it has affected all my recordings since the PSB1 frequency shift. It may not be an intended change, and I don't know if it really is responsible for the WMC problems, but it's there.
VLC media player 2.0.7 Twoflower, Fedora 17
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Emmerdale again. ITV1, Waltham.
7 streams, 4 are video.
Other muxes show only 1 video stream.
Stream 0. Type Video. Original ID 514.
Codec MPEG-1/2 Video (mpgv)
Resolution 704x576. Frame rate 50.
Decoded format Planar 4:2:0 YUV
Stream 1.Type Audio. Original ID 652
Codec MPEG Audio layer 1/2/3 (mpga)
Language English. Channels Stereo.
Sample rate 48000 Hz. Bitrate 192 kb/s
Stream 2. Type Audio. Original ID 662
Codec, Language, as stream 1.
Description: visual impaired commentary
Stream 3. Type Subtitle. Original ID 1027
Codec DVB Subtitles (dvbs)
Language English
Description DVB subtitles
Stream 4. Type Video. Original ID 2051
Codec MPEG-1/2 Video {mpgv)
Stream 5. As stream 4 but ID 2251
Stream 6. As stream 4 but ID 2252
HTH
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All the info I have posted so far has been taken from files recorded by MythTV. I've just tried the VLC 'Codec info' tool while watching live TV with VLC
Media > Open Capture Device > TV (digital) > DVB-T > Mux freq 737833 > Bandwidth 8 Mhz > Play
and selecting within the mux by
Playback > Programme
The stream analysis looks similar and the EPG info comes up too. You might get more insights from this if the Windows version works in the same way. Good luck!
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John: I have emailed as you suggested, with the stream info from my post of 24 June. I've had an auto-reply.
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Since other people were reporting loss of signal it seems likely that the distant transmissions were just being picked up instead where the aerial was suitably pointed.
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I have a response to my email of 10 July. It's similar to John's as reported on 8 July. Mast operator reports no issues, info passed to infrastructure team, will contact me again if they have anything to say. Ho hum.
There has been a change; I've quoted details.
It might be within their specs and I can live with it. Good luck.
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Page 1
Thursday 20 June 2013 10:35PM
Here is a link to a post I made shortly after the Waltham retune of 29 May. Several channels in PSB2 now appear to ffmpeg to have multiple video streams. Before the retune these extra streams were classed as data, as they still are in PSB1. Relabelling of the streams has not affected replay of my recordings but did break a script I used to edit them.
I have had no reports of similar changes from other transmitters.
UK DVB-T Channels 4, 5; multiple video streams | MythTV | Users