Topic: Scheduled recording - recording wrong DVB-T channel (Read 9308 times)

csy · « **on:** May 20, 2012, 02:28:41 am »

I have a peculiar problem when doing scheduled recording on one specific DVB-T channel, that it instead records an adjacent channel off the same mux. What really makes it strange is that while it is recording, it can go into LiveTV on that channel and the time-shifting recording is correct, but if I go to the TV Recording directory and start watching the recording file, it is a different channel (adjacent channel off the same mux).

To double-check, I went back to LiveTV to the active time-shifting recording which is displaying the correct channel and checked the tuner status and verified only one tuner is active, to which LiveTV is showing the correct channel but the recording file is recording a different channel.

Any ideas how to troubleshoot this?

NickF · « **Reply #1 on:** May 20, 2012, 11:47:14 am »

By the way you are describing this, it sounds as though a single tuner is recording one channel and playing another live at the same time. This isn't technically possible. A single tuner can only tune to one channel at a time. So it must be that two tuners are being used. I assume this is going on in Standard View. The question is why does a channel name choose one channel to record and another to play. Where are you choosing the channel to record and where are you choosing the channel to play live?

Nick.

Yaobing · « **Reply #2 on:** May 20, 2012, 03:25:14 pm »

Are you using transport stream format for recording? While the recording is being played, check to see if it has multiple streams.

csy · « **Reply #3 on:** May 21, 2012, 12:34:26 am »

@Yaobing: yes, TS format. Playing the recording back, stream selection shows only one video stream (the incorrect one).

@NickF, you are correct there is only one RF channel, however the RF channel contains a transport stream which contains multiple broadcast stations/channels, known as program ID's (PID's), so in my case the one tuner is receiving one RF channel containing multiple PID's. When I initially scanned the channels on the tuner, it automatically matched the PID's to the channel names via the inband EPG data. This particular station is called "PRIME" and has a specific PID for video and PID for audio, which is predefined. Unfortunately the inband EPG is non-conventional format, so I am using an external EPG source and within MC match the EPG channels to the scanned channels, which is then presented in the MC Guide. Now if I go into the Guide and schedule a program to record on "PRIME", and while recording also watch the program live, then both should be using the same PID's, but what is actually happening is LiveTV is using the correct PID's, but the recording is using the wrong PID's off the same transport stream (RF channel).

Note this issue is only happening on one specific broadcast station. All other DVB-T broadcast stations work fine. So I'm wondering if MC has some corrupt PID numbers that need to be flushed-out and reconfigured. I did try completely delete the MC EPG and remove all channels, then start again with fresh scan on all tuners, and reconfigure EPG and freshly update all EPG data, but that didn't fix the issue.

NickF · « **Reply #4 on:** May 21, 2012, 05:46:25 am »

Quote from: csy on May 21, 2012, 12:34:26 am

@NickF, you are correct there is only one RF channel, however the RF channel contains a transport stream which contains multiple broadcast stations/channels, known as program ID's (PID's), so in my case the one tuner is receiving one RF channel containing multiple PID's.

Thanks csy. I learnt something new today! Often the case here!

Do both channels get identified during the scan? It would be interesting to see the File Names for both. These include all of the parameters including PID etc.

It sounds as though the PIDs are getting mixed up somewhere, assuming it is PID which is used in MC.

Nick.

Yaobing · « **Reply #5 on:** May 21, 2012, 09:27:16 am »

Can you take a look at all the sub channels in the same transport inside MC and see if they all have correct PIDs and other parameters? Are there any duplicate entries in the group that maybe incorrect?

csy · « **Reply #6 on:** May 25, 2012, 12:33:10 am »

I had deleted all the other sub-channels out of MC (for that TS) so it only had PRIME (which again is interesting that MC is recording a sub-channel that it doesn't know about).

I did a new scan and picked-up 8 TV sub-channels plus 3 radio sub-channels on that one transport stream. All sub-channels have unique PID's for video and audio.

'PRIME' video-PID:554, audio-PID:604
The offending recorded channel is 'Parliament TV' video-PID:551, audio-PID:601

(It's a real let-down when you go to watch a recording of SGU and you end-up with politicians debating

)

Yaobing · « **Reply #7 on:** May 25, 2012, 11:42:59 am »

Can you try repeating the issue? If you can repeat it, please send the log files to me.

csy · « **Reply #8 on:** May 26, 2012, 08:45:54 pm »

Issue still exists. This time I left Parliament TV defined in MC (PRIME & Parliament sub-channels defined but deleted all others off TS). Now 'PRIME' scheduled recordings contain 'Trackside' sub-channel. So I'm wondering if the problem relates to me deleting the unwanted sub-channels from MC.

I did a 'PRIME' scheduled recording of 'Great Outdoors' with logging enabled. Please see attached. The recording contents is Trackside.

PRIME video-PID:554, audio-PID:604
Trackside video-PID:552, audio-PID:602

Yaobing · « **Reply #9 on:** May 26, 2012, 10:04:31 pm »

Thanks. Something strange here. We removed a bunch of audio and video PIDs from the stream, but did not remove 552/602, nor did we remove 554/604. So the recording should contain both, not just 552/602.

Would you email me a backup copy of your library? yaobing at jriver dot com

csy · « **Reply #10 on:** May 26, 2012, 11:52:06 pm »

Sent, thanks

Yaobing · « **Reply #11 on:** May 29, 2012, 11:16:21 am »

Thanks for the lib backup.

Your library contains the following TV channels that belong to the same transport
(transport stream ID 33, Network ID 13313, Frequency 70600):

5 PRIME - Service ID 1404, Audio PID 604, Video PID 554
9 Choice TV - Service ID 1407, Audio PID 606, Video PID 556
Parliament TV - Service ID 1401, Audio PID 601, Video PID 551
12 Maori Television - Service ID 1400, Audio PID 600, Video PID 550

When you tried to record PRIME, MC removed the PIDs for the other three channels.

I do not see Trackside in the channel list. Did you remove it? You mentioned previously removing Parliament TV, but not Trackside. Is it a new subchannel that you did not pick up during previous channel scan?

The way it is done in MC, removing a subchannel from the library will have some impact on recording. However, I would expect it still record the intended subchannel. For example, if Trackside is indeed a subchannel that you do not have in your library, then recording PRIME would result in three subchannels being removed from transport stream, but with PRIME and Trackside being left in. So your recording should contain both PRIME and Trackside subchannel streams.

csy · « **Reply #12 on:** May 31, 2012, 04:34:35 pm »

Yes I removed Trackside and 4 other unwanted TV sub-channels, plus removed 3 unwanted radio sub-channels.

I have taken the recording and opened it in VideoReDo, and you are abosolutely correct, it does contain PRIME plus all the removed sub-channels (5 TV + 3 radio sub-channels recorded)

So MC appears to be randomly selecting which sub-channel to view from the recording. Interestingly, while the recording is playing in MC, and I go to the right-click-menu to select the video & audio streams, only the currenlty playing video/audio stream is available and no others.

So where to from here? I should not have to define all the unwanted sub-channels (TV & radio) in order for MC to record only the chosen sub-channel. This is also important for data volume efficiency.

Edit: An option would be to do the same as WMC where all the scanned channels are defined but unwanted channels can be disabled from LiveTV / Guide.

Sandy B Ridge · « **Reply #13 on:** May 31, 2012, 05:30:02 pm »

Quote from: Yaobing on May 29, 2012, 11:16:21 am

The way it is done in MC, removing a subchannel from the library will have some impact on recording. However, I would expect it still record the intended subchannel. For example, if Trackside is indeed a subchannel that you do not have in your library, then recording PRIME would result in three subchannels being removed from transport stream, but with PRIME and Trackside being left in. So your recording should contain both PRIME and Trackside subchannel streams.

There are probably good programming reasons to do it this way, but it does seem rather bizarre to me....

If it is setup in this way, then surely it must be easy to implement recording two separate channels from the same mux???

SBR

Yaobing · « **Reply #14 on:** June 01, 2012, 08:38:36 am »

Quote from: csy on May 31, 2012, 04:34:35 pm

So MC appears to be randomly selecting which sub-channel to view from the recording. Interestingly, while the recording is playing in MC, and I go to the right-click-menu to select the video & audio streams, only the currenlty playing video/audio stream is available and no others.

Probably this is an issue in LAV splitter filter. I am guessing it renders only the first service appearing in the file.

Quote

So where to from here? I should not have to define all the unwanted sub-channels (TV & radio) in order for MC to record only the chosen sub-channel. This is also important for data volume efficiency.

As we try to figure out a better way to handle this situation, you have two options in the mean time:

Do not delete any subchannels, but use "Favorite" keyword in all channels you want (or do the opposite, by using "Ignore" keyword in all unwanted channels). You can then configure Theater view to display only the channels that you want.

Or live with the larger sized ts recording and use Haali Media Splitter instead of LAV splitter to play the TS files. With Haali Splitter you can select different subchannels while you play.

Quote from: Sandy B Ridge on May 31, 2012, 05:30:02 pm

There are probably good programming reasons to do it this way, but it does seem rather bizarre to me....

I did it this way because I was afraid of removing too many packets from the transport. So instead of saying "keep such and such packets...", the list of which may be long and I may miss some, I say "remove these packets that I know definitely are not needed, and keep the rest".

I should gain better knowledge of MPEG-2 transport stream, then I can try using an inclusion list instead of an exclusion list.

Quote

If it is setup in this way, then surely it must be easy to implement recording two separate channels from the same mux???

Yes. It would not be too hard to implement for recording in TS format. I guess this is another reason for choosing TS over jtv.

Sandy B Ridge · « **Reply #15 on:** June 01, 2012, 10:01:39 am »

Quote

Do not delete any subchannels, but use "Favorite" keyword in all channels you want (or do the opposite, by using "Ignore" keyword in all unwanted channels). You can then configure Theater view to display only the channels that you want.

Given your explanation as to how this works, then I will definitely do this.

A proposal for a short term fix:
Why not change the behaviour of the TV Channel dialogue so that it adds the keyword 'Deleted' to the channel instead of getting rid of it from the library completely. The channel list in TV under Devices could then just ignore those ones. TheaterView default EPG could come pre-programmed to ignore the ones with 'Deleted' keyword.

I might try Haali over the weekend with the HD mux to see if it works for multiple HD stream recording. It would be great to see this working before the Olympics. The BBC will have 24 HD channels of sport (all FTA) on DVB-S on new muxes and recording all of these at once would be great!

SBR

NickF · « **Reply #16 on:** June 01, 2012, 12:04:28 pm »

Hmmm! I've been watching this thinking, thank goodness this doesn't affect me, having gone through the whole scanning, weeding, tagging and guide building process again, for the last time ever, I thought. Now you seem to be suggesting that this affects us in the UK too. I think I'm going to cut my throat. This is just too hard..... I can see that Green Button on my desktop and its very enticing.

So how de we decide which channels are affected or is it all? How do we know what is a sub-channel?

And I was so looking forward to spending the whole weekend celebrating the Jubilee!

Nick.

Yaobing · « **Reply #17 on:** June 01, 2012, 12:39:49 pm »

sub-channels refer to channels that are on the same transport. For DVB, this means all channels that share the same transport stream ID (TSID). For ATSC, they are all channels that share the same physical channel. Sub-channel probably is an ATSC concept (channels 5-1 and 5-2 are two sub-channels from the station that used to use channel 5 for analog TV).

Sandy B Ridge · « **Reply #18 on:** June 01, 2012, 12:52:21 pm »

Quote from: NickF on June 01, 2012, 12:04:28 pm

Hmmm! I've been watching this thinking, thank goodness this doesn't affect me, having gone through the whole scanning, weeding, tagging and guide building process again, for the last time ever, I thought. Now you seem to be suggesting that this affects us in the UK too. I think I'm going to cut my throat. This is just too hard..... I can see that Green Button on my desktop and its very enticing.

So how de we decide which channels are affected or is it all? How do we know what is a sub-channel?

And I was so looking forward to spending the whole weekend celebrating the Jubilee!

Nick.

Shouldn't take too long Nick.

Add a keyword (temporarily) to the channels you want to keep. Ctrl-A in the channel list and F2 and tag with 'Keep'.
Rescan your DVB S & T channels. Select the untagged ones and F2 and tag with 'Delete'.

Add a rule to your Theaterview EPG to exclude ones tagged with Delete.

Simples!

SBR

csy · « **Reply #19 on:** June 01, 2012, 02:30:12 pm »

Thanks Yaobing, I appreciate your support.

I came to the same conclusion that I must have all sub-channels defined which I've now done via a re-scan, and I can now happily record and play PRIME scheduled recordings.

Thanks for the suggestion of using 'favorite' keyword, then config Theater View to display only those. I'm not sure how to do this but I'll have a play

Sandy B Ridge · « **Reply #20 on:** June 01, 2012, 03:37:53 pm »

Quote from: csy on June 01, 2012, 02:30:12 pm

Thanks for the suggestion of using 'favorite' keyword, then config Theater View to display only those. I'm not sure how to do this but I'll have a play

See NickFs great wiki topic on this. There's a set way of doing it!

SBR

NickF · « **Reply #21 on:** June 01, 2012, 04:18:55 pm »

Quote from: Sandy B Ridge on June 01, 2012, 12:52:21 pm

Shouldn't take too long Nick.

Add a keyword (temporarily) to the channels you want to keep. Ctrl-A in the channel list and F2 and tag with 'Keep'.
Rescan your DVB S & T channels. Select the untagged ones and F2 and tag with 'Delete'.

Add a rule to your Theaterview EPG to exclude ones tagged with Delete.

Simples!

SBR

So when I re-scan, do I end up with duplicates of the ones I marked "Keep"? And I will end up with a channel list of millions of channels with all those encrypted ones, the porn and all the other stuff I just don't want.

And now, when we record, we have to try to find the channel we wanted to record amongst multiple streams, having to use a mouse or keyboard, rather than a remote.

This is a mess and needs to be sorted urgently.

Edit: sorry, got a bit over excited. Must be the four days of Jubilee celebrations ahead.

.....I'm sure that green button is bigger than it was.

Nick.

NickF · « **Reply #22 on:** June 01, 2012, 05:58:51 pm »

Does this mean that each time we record an HD channel, we burn up umpteen gigabytes or storage with all the other HD channels in the same TSID?

And do we have to pass all that bandwidth across our networks to and from our NAS drives? Will my HDDs even handle that bandwidth?

I can feel myself getting a bit excited again. Back to the Jubilee.

Nick.

Yaobing · « **Reply #23 on:** June 01, 2012, 06:10:21 pm »

Quote from: NickF on June 01, 2012, 05:58:51 pm

Does this mean that each time we record an HD channel, we burn up umpteen gigabytes or storage with all the other HD channels in the same TSID?

If you record in TS format and if you had deleted some channels, then the deleted channels will appear in the recording of a not-deleted channel. If you had not deleted any channel (but use keyword to exclude channels) then each recording will only contain the intended recording.

NickF · « **Reply #24 on:** June 01, 2012, 06:24:13 pm »

Quote from: Yaobing on June 01, 2012, 06:10:21 pm

If you record in TS format and if you had deleted some channels, then the deleted channels will appear in the recording of a not-deleted channel. If you had not deleted any channel (but use keyword to exclude channels) then each recording will only contain the intended recording.

So if the unwanted channels are in the library but not in the guide, we are OK?

Nick.

Yaobing · « **Reply #25 on:** June 01, 2012, 07:14:09 pm »

Quote from: NickF on June 01, 2012, 06:24:13 pm

So if the unwanted channels are in the library but not in the guide, we are OK?

Yes.

Sandy B Ridge · « **Reply #26 on:** June 02, 2012, 01:12:50 am »

Quote from: NickF on June 01, 2012, 04:18:55 pm

So when I re-scan, do I end up with duplicates of the ones I marked "Keep"?

No, I don't think duplicates (exact copies) are made in the library. You'll get lots of (1)channels with other audio tracks etc. The ones you previously deleted.

Quote

And I will end up with a channel list of millions of channels with all those encrypted ones, the porn and all the other stuff I just don't want.

They'll be in the library for sure, but only be listed unless you put in a rule to exclude them: ie. Exclude channels containing 'Deleted' in the smartlist properties.

Quote

And now, when we record, we have to try to find the channel we wanted to record amongst multiple streams, having to use a mouse or keyboard, rather than a remote.

No, only the ones marked not 'Deleted' appear in the EPG if you set up the rule correctly. So your EPG will look exactly the same.

Quote

This is a mess

Agree it's a bit of a mess!

SBR

NickF · « **Reply #27 on:** June 02, 2012, 02:58:35 am »

OK, I'm going for it! I'm going to back up my library first.

If I come out the other end in one piece, I'll update the wiki to reflect the outcome of this discussion. I realise this may only be temporary until Yaobing comes up with some clever solution - no pressure, Yaobing!

Nick.

Sandy B Ridge · « **Reply #28 on:** June 02, 2012, 03:38:23 am »

DVB-S tuning seems to put every single channel in the library, but DVB-T seems to exclude some. I assume it is the 'encrypted' ones with no valid Audio & Video PID in the lookup table. The log shows these channels whilst tuning, but they never appear in MC's channel list or the library. Does this mean that these streams are also recorded with the intended subchannel since they aren't in the library? Does the DVB T tuning engine need tweaking to include these in the library too? Otherwise they get recorded too.

BTW these DVB T channels aren't 'encrypted' as such, the PIDs are hidden in MHEG (IIRC) code.

SBR

NickF · « **Reply #29 on:** June 02, 2012, 04:14:59 am »

Quote from: Sandy B Ridge on June 02, 2012, 03:38:23 am

DVB-S tuning seems to put every single channel in the library, but DVB-T seems to exclude some. I assume it is the 'encrypted' ones with no valid Audio & Video PID in the lookup table. The log shows these channels whilst tuning, but they never appear in MC's channel list or the library. Does this mean that these streams are also recorded with the intended subchannel since they aren't in the library? Does the DVB T tuning engine need tweaking to include these in the library too? Otherwise they get recorded too.

BTW these DVB T channels aren't 'encrypted' as such, the PIDs are hidden in MHEG (IIRC) code.

SBR

I'm not sure which DVB-T channels you are referring to. I see Sky Sports 1 and 2, for example. They both appear in the library and show valid PIDs.

Nick.

Sandy B Ridge · « **Reply #30 on:** June 02, 2012, 05:17:28 am »

Quote from: NickF on June 02, 2012, 04:14:59 am

I'm not sure which DVB-T channels you are referring to. I see Sky Sports 1 and 2, for example. They both appear in the library and show valid PIDs.

I can't remember what they are called, they are the dodgy payTV ones, I'll retune later and let you know if you like. They are the ones you can access with the red button, but don't need a smart card for. They 'hide' by not having a valid PID until you enable them via the red button MHEG code. If you had the PID they would be manually tuneable. It works this way so that they can make Freeview TVs without CAMs and PayTv can still make money from you.

For Sky Sports you need a card and CAM. I think it is still via TopupTV. So they are true encrypted and need the CAM/Card for decrypting. So they have a valid PID in the lookup table -- no need to 'hide' it since you can't view the stream without means to decrypt it.

The satellite Market is sewn up by Sky so most will have the skybox to Descramble the channels, so channels on dvbs aren't hidden in the same way.

SBR

NickF · « **Reply #31 on:** June 07, 2012, 07:14:20 am »

I have now updated the Television instructions in the wiki advising users not to delete channels.

Nick.

Sandy B Ridge · « **Reply #32 on:** July 26, 2012, 06:15:24 pm »

Now that MC18 is being worked on, I'd suggest that this mess is given priority in the development cycle. It just does not make sense for a DVB program to record streams in this way.

DVB-T in the UK has 5 muxes of channels (1 x HD and 4 x SD). I would like to delete all the shopping channels and porn channels from the library. However if I do this, then by recording an SD channel I have a 50% chance of inadvertently recording a porn channel stream onto my PC (since 2 muxes carry such channels). This is wholly unacceptable.

Please find a way of just recording the sub-stream that I actually want... rather than stuff that I don't want.

SBR

Edit: Oops, wrong facts-I just checked my local transmitter. 6 muxes, 5 SD, 4 contain porn! So 80% chance of recording garbage. Yuk!

pahunt · « **Reply #33 on:** July 27, 2012, 01:20:51 am »

Quote from: Sandy B Ridge on July 26, 2012, 06:15:24 pm

Now that MC18 is being worked on, I'd suggest that this mess is given priority in the development cycle. It just does not make sense for a DVB program to record streams in this way.

DVB-T in the UK has 5 muxes of channels (1 x HD and 4 x SD). I would like to delete all the shopping channels and porn channels from the library. However if I do this, then by recording an SD channel I have a 50% chance of inadvertently recording a porn channel stream onto my PC (since 2 muxes carry such channels). This is wholly unacceptable.

Please find a way of just recording the sub-stream that I actually want... rather than stuff that I don't want.

SBR

Edit: Oops, wrong facts-I just checked my local transmitter. 6 muxes, 5 SD, 4 contain porn! So 80% chance of recording garbage. Yuk!

I agree with this 100%. If this could be sorted I could finally get rid of WMC completely.

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Author Topic: Scheduled recording - recording wrong DVB-T channel (Read 9308 times)