OpenDCT: An open source digital cable tuner.

[EnterNoEscape]

Originally Posted by jarredduq

I'm running 0.5.8 beta and Comcast has started migrating more channels to h.264. I've noticed that tuning is extremely slow for the channels on h.264. It's around 15 seconds compared to about 3 with MPEG2. Also, it comes up with the no signal message for about 5 seconds before the video starts playing.

It's working, but I'm wondering if there is a setting I need to change to speed up the tuning.

Thanks in advance.

Based on how long it's taking for OpenDCT to determine what streams are available, there's a good chance that Comcast mangled the PAT or PMT packets. That would imply the video and audio streams are present, but the packets that allow us to know what belongs to what are missing, so after some time it's assumed that whatever video stream and audio streams were discovered must be the content we want to stream.

There is another related possibility if you're using an HDHomeRun Prime. We've had a few users whereby the PMT packet appears to not get decrypted by the HDHomeRun. I didn't make any correlations to the H.264 codec. If this is what's happening, it's an outstanding issue for the built-in SageTV remuxer too since it doesn't handle the situation and someone needs to fix it so it can deal with it correctly. I haven't seen this happen to me once and I'm using the media server remuxer (SageTV built-in) full time in production. I'm also running the 20160426atest1 beta firmware.

[jarredduq]

Originally Posted by EnterNoEscape

Based on how long it's taking for OpenDCT to determine what streams are available, there's a good chance that Comcast mangled the PAT or PMT packets. That would imply the video and audio streams are present, but the packets that allow us to know what belongs to what are missing, so after some time it's assumed that whatever video stream and audio streams were discovered must be the content we want to stream.

There is another related possibility if you're using an HDHomeRun Prime. We've had a few users whereby the PMT packet appears to not get decrypted by the HDHomeRun. I didn't make any correlations to the H.264 codec. If this is what's happening, it's an outstanding issue for the built-in SageTV remuxer too since it doesn't handle the situation and someone needs to fix it so it can deal with it correctly. I haven't seen this happen to me once and I'm using the media server remuxer (SageTV built-in) full time in production. I'm also running the 20160426atest1 beta firmware.

I enabled the following: consumer.ffmpeg.h264_pts_hack=true. Now it tunes normally on the H.264 stations.

I'm on 20160630atest2 firmware.

[EnterNoEscape]

I'm fairly certain that didn't do anything for you if you're running the latest beta since that feature has been removed because it actually did more harm than good and was there for slower Android devices. I usually don't remove properties from opendct.properties, so it's probably still there from a previous upgrade. However, I am glad things seem to be working better for you.

[LaoChe]

I was referred to the OpenDCT project as a possible solution to my problem but after browsing through about 20 pages of this forum as well as the GitHub site I am having trouble figuring out if this will actually help or what it even does.

My problem is that my entire cable lineup as far as I can tell is broadcast in unencrypted clearQAM but the channels seem to be constantly changing. If I run a channel scan in Sage I will get 120 channels that all map correctly and can be viewed (i.e. 55-0-549 maps to channel 549 AMC) but if I run another scan 5 minutes later all the channels will have changed. Some new ones will show up but every single channel that I've already mapped will have changed (i.e 55-0-549 can no longer be tuned but now 122-0-549 is tuneable and maps to channel 549 AMC). I keep rescanning because there always seem to be a few channels missing.

Somebody said that OpenDCT might be able to look at the last part of the channel and keep me from losing all of my mappings but I can't figure out if that is really something it does. If so a follow up question would be can it retain override information for channels that don't map exactly as they should (e.g. 122-0-721 and 55-0-721 and 62-0-721 all actually map to channel 521, not 721).

I apologize for such a dumb question but I have spent an hour already looking through postings and the GitHub site and I would like to find out if this is even a potential solution to my problem before I keep reading any more.

Edit: somebody suggested this might be an issue with switched digital video - not sure if that changes the answer.

Thanks a lot.

[Fuzzy]

Originally Posted by LaoChe

I was referred to the OpenDCT project as a possible solution to my problem but after browsing through about 20 pages of this forum as well as the GitHub site I am having trouble figuring out if this will actually help or what it even does.

My problem is that my entire cable lineup as far as I can tell is broadcast in unencrypted clearQAM but the channels seem to be constantly changing. If I run a channel scan in Sage I will get 120 channels that all map correctly and can be viewed (i.e. 55-0-549 maps to channel 549 AMC) but if I run another scan 5 minutes later all the channels will have changed. Some new ones will show up but every single channel that I've already mapped will have changed (i.e 55-0-549 can no longer be tuned but now 122-0-549 is tuneable and maps to channel 549 AMC). I keep rescanning because there always seem to be a few channels missing.

Somebody said that OpenDCT might be able to look at the last part of the channel and keep me from losing all of my mappings but I can't figure out if that is really something it does. If so a follow up question would be can it retain override information for channels that don't map exactly as they should (e.g. 122-0-721 and 55-0-721 and 62-0-721 all actually map to channel 521, not 721).

I apologize for such a dumb question but I have spent an hour already looking through postings and the GitHub site and I would like to find out if this is even a potential solution to my problem before I keep reading any more.

Edit: somebody suggested this might be an issue with switched digital video - not sure if that changes the answer.

Thanks a lot.

You will need a CableCard tuner, and a Tuning Adapter (provided by the cablecompany along with the CableCard) to use an SDV network. When you DO get these things, OpenDCT is what will connect them to SageTV.

[EnterNoEscape]

Originally Posted by Fuzzy

You will need a CableCard tuner, and a Tuning Adapter (provided by the cablecompany along with the CableCard) to use an SDV network. When you DO get these things, OpenDCT is what will connect them to SageTV.

I'll add that if your provider uses SDV, ClearQAM will be a very unreliable path. I would just get a CableCARD tuner. You'll just have a lot of headaches if you don't.

[tmiranda]

I read in another thread that if I have OpenDCT configured on a cablecard tuner I can also use it to tune ClearQAM channels on another tuner. How do I do that?

I my case I have a HDHomeRun Prime configured using OpenDCT and an old HDHomeRun that I have manually remapped all of the channels. I think if I use OpenDCT to tune the old HDHomeRun I won't have to worry about remapping, is that correct?

[EnterNoEscape]

Correct. It should determine that the Prime has a CableCARD present and it will use that to tune old HDHomeRun. In fact what you're describing is very close to what I'm doing at my house. All you need to do is use the old HDHomeRun through the OpenDCT network encoder instead of directly though SageTV.

All SageTV does is give OpenDCT a normal virtual channel to tune, OpenDCT looks the channel up if it doesn't already know the mapping, then it tunes the channel in by frequency and program on the ClearQAM tuner.

The only thing I will mention for HDHomeRun exclusive owners is that OpenDCT does actually need to tune the channel in on the Prime (less than 100ms) to get the frequency and program information, but since this is cached (to disk), it only needs to do that once. To completely avoid this issue, tune into your ClearQAM channels ahead of time and then it won't matter if no CableCARD tuners are available at the moment because there won't be any new mappings that need to be looked up. This is not a problem for InfiniTV owners because the InfiniTV provides an entire table of all the mappings.

If you wanted to reset the remapping "cache," you could just delete the associated lineup from the OpenDCT config/lineups directory. This caching is why I don't recommend using this approach for constantly changing mappings (SDV).

[Fuzzy]

Originally Posted by EnterNoEscape

Correct. It should determine that the Prime has a CableCARD present and it will use that to tune old HDHomeRun. In fact what you're describing is very close to what I'm doing at my house. All you need to do is use the old HDHomeRun through the OpenDCT network encoder instead of directly though SageTV.

All SageTV does is give OpenDCT a normal virtual channel to tune, OpenDCT looks the channel up if it doesn't already know the mapping, then it tunes the channel in by frequency and program on the ClearQAM tuner.

The only thing I will mention for HDHomeRun exclusive owners is that OpenDCT does actually need to tune the channel in on the Prime (less than 100ms) to get the frequency and program information, but since this is cached (to disk), it only needs to do that once. To completely avoid this issue, tune into your ClearQAM channels ahead of time and then it won't matter if no CableCARD tuners are available at the moment because there won't be any new mappings that need to be looked up. This is not a problem for InfiniTV owners because the InfiniTV provides an entire table of all the mappings.

If you wanted to reset the remapping "cache," you could just delete the associated lineup from the OpenDCT config/lineups directory. This caching is why I don't recommend using this approach for constantly changing mappings (SDV).

How does OpenDCT know to do this? I ask because I've got a Prime connected to my cable, and was going to connect an old HDHR to my antenna, and was planning on using OpenDCT for it as well, but don't want it trying to tune it to QAM channels simply because a Prime is configured as well.

[EnterNoEscape]

OpenDCT is passive by default. OpenDCT will not reconfigure your HDHomeRun devices unless you explicitly edit opendct.properties to do so; by default it uses them as you last configured them and does not enforce your last configuration in any way. If you have it set to ATSC on the HDHomeRun, it will remain ATSC.

If you have a tuner set up to use ClearQAM, but don't use the tuner via OpenDCT, it will not perform lookups on your HDHomeRun Prime even if the tuner is loaded. If you are paranoid, you can also exclude capture devices from being loaded all together.

[Fuzzy]

Originally Posted by EnterNoEscape

OpenDCT is passive by default. OpenDCT will not reconfigure your HDHomeRun devices unless you explicitly edit opendct.properties to do so; by default it uses them as you last configured them and does not enforce your last configuration in any way. If you have it set to ATSC on the HDHomeRun, it will remain ATSC.

If you have a tuner set up to use ClearQAM, but don't use the tuner via OpenDCT, it will not perform lookups on your HDHomeRun Prime even if the tuner is loaded. If you are paranoid, you can also exclude capture devices from being loaded all together.

Not a matter of paranoia, just curious. I do see now that there is a property to disable the feature, and also see that it handles it differently if the tuner is set to ATSC anyway.

[jarredduq]

Originally Posted by EnterNoEscape

I'm fairly certain that didn't do anything for you if you're running the latest beta since that feature has been removed because it actually did more harm than good and was there for slower Android devices. I usually don't remove properties from opendct.properties, so it's probably still there from a previous upgrade. However, I am glad things seem to be working better for you.

It definitely does something, because if I turn it off, the tuning becomes slow again. LOL

[EnterNoEscape]

Originally Posted by jarredduq

It definitely does something, because if I turn it off, the tuning becomes slow again. LOL

That's so weird. I did a full text search of the entire project and the only hit I get is the release notes.

[Brent94Z]

I just wanted to again express my THANKS for this addition to my SageTV setup. It has been fantastic. I installed it back in March and it 'just works'. I've not updated to any newer version because it works so good, I don't want to mess anything up. LOL

Anyway, thank you again and keep up the good work!

[mgpaulus]

I've been beating the snot out of my system during the Olympics with 2 HDHR-3CC Prime and a DCR-2650, giving me 8 channels to tune. Mostly it has been all good, non-stop for a week. However, yesterday, it all went south, with some Unhandled NullPointerExceptions, and then, it hit an OutOfMemory Exception, and all my tuners went away until I rebooted.

I was wondering if you wanted to look at the log to see what is going on with that many devices? Is there any way to have this stuff in multiple JVMs so the OutOfMemory is not so easy to hit?

I'm running on a box with Win7-64bit, 8-core Vishnu AMD proc, and 16GB of Ram. As per the recommendations from this set of boards, I am running 32-bit Java.

[EnterNoEscape]

The latest beta addresses the OOM errors. I've never run into them, but it seems some people such as yourself have and they are the result of lots of re-allocating a relatively large buffer in direct memory for the capture devices. I suspect it's not so much as you're out of memory so much as it's fragmented and can't find a large enough contiguous location.

[Fuzzy]

Originally Posted by mgpaulus

I've been beating the snot out of my system during the Olympics with 2 HDHR-3CC Prime and a DCR-2650, giving me 8 channels to tune. Mostly it has been all good, non-stop for a week. However, yesterday, it all went south, with some Unhandled NullPointerExceptions, and then, it hit an OutOfMemory Exception, and all my tuners went away until I rebooted.

I was wondering if you wanted to look at the log to see what is going on with that many devices? Is there any way to have this stuff in multiple JVMs so the OutOfMemory is not so easy to hit?

I'm running on a box with Win7-64bit, 8-core Vishnu AMD proc, and 16GB of Ram. As per the recommendations from this set of boards, I am running 32-bit Java.

Also realize, that you CAN have 32-bit java and 64-bit java coexisting perfectly fine on a system - so you can use the 64-bit install of OpenDCT on your sagetv server, even if you don't use the 64-bit JVM for sage.

[boukmandutty]

So I just installed OpenDCT and notice a stutter/freeze in my video playback that wasn't there when I was using SageDCT.

To make sure it wasn't a video codec or hardware problem I tuned to the same channel on the same tuner in Windows Media Center and it plays smoothly. So do all my other channels.

When I look at the hdhomerun prime while using Sage with OpenDCT the tuner light blinks on and off. It doesnt do this for Windows Media Center and never did this when I was using SageDCT.

I am using the latest beta version.

[EnterNoEscape]

Originally Posted by boukmandutty

So I just installed OpenDCT and notice a stutter/freeze in my video playback that wasn't there when I was using SageDCT.

To make sure it wasn't a video codec or hardware problem I tuned to the same channel on the same tuner in Windows Media Center and it plays smoothly. So do all my other channels.

When I look at the hdhomerun prime while using Sage with OpenDCT the tuner light blinks on and off. It doesnt do this for Windows Media Center and never did this when I was using SageDCT.

I am using the latest beta version.

Please post the logs. (Windows: C:\ProgramData\OpenDCT\logs\opendct.log)

[boukmandutty]

I think it might have been network related. I use a MoCA network hacked up via some fios modems to get my cox connection between rooms (I hate cox!). I noticed that when I plug the hdhomerun prime directly into the cable modem there is no stutter or any sort. I notice it still takes me a long time to tune channels though.

What I did notice this evening though is a recording failure that seems to have been caused by my windows media center computer using the tuner at the same time.

Does opendct move automatically to the next tuner if the one assigned for a recording is being used? I actually have to use Windows Media center because everything except local channels has drm (I hate cox so much!). Doesn't OpenDCT play nice with other programs?

My log is attached.