HDPVR Commercial Detection

[Taddeusz]

I've been using ShowAnalyzer 1.0 for commercial detection. Previously I was using the donator version of comskip for this purpose but I switched due to the fact that SA is MUCH faster. With both programs I've always had the issue of the detected commercial segments being off by a small amount. Sometimes several seconds. Enough that it is quite noticeable.

Well, today I was playing around some more with SAV1 and was playing the program as it was being recorded and simultaneously being detected. While it was still being recorded the commercial segments were dead-on accurate but as soon as it completed the segments were off. If I run SAV1 on a file that has already completed the segments will be off.

This means one of two things. Either the timing for completed HDPVR recordings off by a small amount or SAV1 isn't detecting the timing correctly. Since I had the same problem with both comskip and SAV1 I'm tending to lean more towards it being a playback timing problem in SageTV. My brain can't seem to explain it any other way. SageTV has no problems with the EDL files created for my HDHR recordings. Only my HDPVR recordings are affected.

BTW, using my HD100 and SageTV Client for playback. Both are affected the same.

I'm currently troubleshooting this with Jere and made a support request with SageTV. Just wondering what other's experience is with this?

[razrsharpe]

how do the commercials line up in VRD? If they are accurate in VRD then (I think) that would point to a problem in SageTV in either how its calculating the timestamp (is it from the beginning of the file, the airing start time (with/without padding), etc) or is the logic that the STVi uses to turn the edl timestamps into jump points wrong?

[bialio]

It seems unlikely that the STVi (or SageMC's built in edl parsing) would be wrong on .ts HDPVR edl files but right on .mpg HDHR .edl files....

btl.

[razrsharpe]

Originally Posted by bialio

It seems unlikely that the STVi (or SageMC's built in edl parsing) would be wrong on .ts HDPVR edl files but right on .mpg HDHR .edl files....

btl.

agreed (i would even say highly unlikely) but it is something to (mildly) consider...

[bialio]

Taddeusz - how long are you seeing SAV1 taking on HDPVR recordings?

I also notice that the commercial breaks are usually off - they end early usually - so that if I skip ahead I get the last bit of commercials before the show resumes. I never actually look closely at where the commercial break _starts_ - since I don't have the auto-skip turned on it doesn't really impact me if the front part of the break is off a little.

btl.

[Taddeusz]

Depends, I think about 5-10min for a 30min recording and about 10-20min for an hour long one. But I usually have it do live detection using SJQ which is how I discovered that the segments were dead-on while still recording.

The segments always start early and end early. The amount of time is variable.

[Taddeusz]

Ok, had to do a few things. Downloaded and installed the beta version of VRD v4 and set SAV1 to create vprj files. In VRD the commercial segments are dead-on accurate but in SageTV they are off.

[bialio]

That tracks on all points with what I'm seeing - about 20 minutes for an hour. Do you find that SAV1 is fast enough to keep up when you are viewing live? It would appear that based purely on numbers it can - ie it can process 3 hour long shows in 60 minutes of real time, but I don't know if the output while live really tracks at that speed......

[razrsharpe]

Originally Posted by Taddeusz

The segments always start early and end early. The amount of time is variable.

Originally Posted by Taddeusz

Ok, had to do a few things. Downloaded and installed the beta version of VRD v4 and set SAV1 to create vprj files. In VRD the commercial segments are dead-on accurate but in SageTV they are off.

then to me that means that sage is somehow mangling the current time into the mediafile....

are the commercials off the same amount through the show, or do they get progressively worse with each commercial?

[razrsharpe]

Originally Posted by bialio

but I don't know if the output while live really tracks at that speed......

why wouldn't it? its detecting faster then real-time so i think its a safe assumption that it should be able to keep up in real-time with a recording in progress (obviously delayed by a couple secs)

[bialio]

are the commercials off the same amount through the show, or do they get progressively worse?

what a good question - I like the way you think. For me they get progressively worse - the first commercial break is usually right on.

btl.

[razrsharpe]

Originally Posted by Taddeusz

Depends, I think about 5-10min for a 30min recording and about 10-20min for an hour long one.

maybe i should give the new sav1 a go... currently im using comskip and i think it takes about an hour processing for an hour show (at least the last time i checked)...

[bialio]

When I've watched SAV1 doing it's thing (yes I was bored out of my mind ) it seemed like it would make it all the way through the file and then backtrack some (based on the percent done meter) so I'm not sure if it actually depends on there being a complete file to figure out all of whatever it's figuring out.

[Taddeusz]

Originally Posted by bialio

That tracks on all points with what I'm seeing - about 20 minutes for an hour. Do you find that SAV1 is fast enough to keep up when you are viewing live? It would appear that based purely on numbers it can - ie it can process 3 hour long shows in 60 minutes of real time, but I don't know if the output while live really tracks at that speed......

Yes, I think it's probably fast enough to keep up with live viewing. That really depends on your processor though. I have a 2.33Ghz C2D E6550. But I also limit SAV1 to 8MB/s. That allows it to be a little faster than real-time but not use a whole lot of CPU or disk access.

[Taddeusz]

Originally Posted by bialio

what a good question - I like the way you think. For me they get progressively worse - the first commercial break is usually right on.

btl.

Yea, I agree... unless the beginning of the recording is a different resolution the first ad break is the closest to being correct and they progressively get further off.

[bialio]

I've got a 2.9Ghz AMD of some variety or the other - how do you set the limit in SAV1? I know there's a spot in the UI about disk access (default value appears to be 15?) - is that what you change to 8?

[Taddeusz]

Originally Posted by bialio

I've got a 2.9Ghz AMD of some variety or the other - how do you set the limit in SAV1? I know there's a spot in the UI about disk access (default value appears to be 15?) - is that what you change to 8?

Yes, you can limit it globally and per instance, or both. I have mine limited per instance.

[razrsharpe]

and mpgs are always correct? And how far off are they by the end?

To me that means that perhaps sage is incorrectly calculating the current time into the file for ts files (GetMediaTime)... maybe the difference between 29.97 and 30 fps (108 frames for 1 hr of video... or ~3.6 secs)

[Taddeusz]

Ok, I have a 30min recording that the end of the last commercial segment ends about 12 seconds too early

[Taddeusz]

Then I have a 1hr recording that is only about 8sec off at the end.