Very strange HD issue

[brianvlee]

I'm having an issue with OTA HD that very well may sound ridiculous.

Prime time shows I watch live or record on ABC & NBC are choppy. It's kind of hard to explain, but it's like there's frame skipping. I'd blame the signal; however, if I record something later on the same station aired in HD (for instance, "The Tonight Show"), the recording plays back perfectly smoothly. But if I record "Chuck" or "Las Vegas", choppiness. I've not had a problem with anything aired on FOX or CBS.

I'm willing to blame this problem on a new computer build, as my last computer didn't have the issue and I'm using the same tuners. I was using BTV 4.5 on that machine, but reverting to that version didn't fix the problem so I don't think I can fault BTV. But I can't think of a way to pin down the issue when HD plays back fine on other stations, leaving me to think there are no playback settings I need tweak, and other shows recorded on the same stations giving me issues at different times also play back without problems. Like I said, it's an odd issue. Any thoughts?

[aknisley]

I am having the same kind of problem. I am trying the trial version right now to see how it works. I have analog cable and OTA hooked up.
The analog cable seems to stream and buffer ok but the digital OTA is choppy.

[bits]

The choppy playback of HD video is probably caused by high bit rates which your current video card (not capture/tuner card) and drivers can not handle. Keep in mind that not all HD broadcasts have the same bit rate. In my area of the 3rd rock from the sun, most OTA HD is 12-14Mb/s BUT sometimes it is 18-20Mb/sec. From one week to the next it can change on some stations. Start tracking the choppy playback shows and I bet you will find that they are the ones with the highest bit rates!

There are a few combinations of video card and drivers that others claim will play all HD smoothly but for the most part high bit rate HD is difficult to play back smoothly. A few of the newer net worked media players can play them but that is about it.

[Rich A]

I would say your computer setup is easily capable of handling any kind of digital playback. It could be some configuration of the components that is giving you trouble. Here's how I would troubleshoot this.

First find the highest HD recorded show you can. When playing back you can see all the details (720 1080 Dolby 5.1 etc) in the area at the bottom of the screen when you hit the correct button on your remote or keyboard. I don't recall what that button is, (I'm using a programmed Harmony Remote myself and haven't changed anything in that area for almost four years now) I think it would be return button on your keyboard.

Anyway you should look for a 1080 recording. Exit BTV and try running that file with some other application. Like Windows Media Player or VLC or some other stand alone player. To really be sure you should not just exit BTV but actually shut it down for this test.

If it plays back smoothly there, then you've narrowed down the problem to some component or setting that BTV is using.

One thing I am concerned about is your Raid 0 array. Is that your only drive in this setup? In other words are you using the Raid array as your boot drive? I also have a Raid 0 setup in my HTPC, BUT it is dedicated to show storage only. I have a separate physical drive that my OS and programs reside on. There have been long and drawn out discussions about the reliability of Raid 0 setups and I hope we don't get mired down in that here. BUT the problem with a Raid 0 being your ONLY drive in a BTV environment is that not only will you have all the Windows house-keeping being done there, (swap file etc) but you would also have all the applications running there, as well as the BTV recordings.

Granted a Raid 0 will indeed make a notable difference in drive access speed, but with today's SATA HDs you really don't need it for your OS drive. I have my Raid 0 set up for show storage and it goes back to the days when drives were maxed out at 120 GB or less. At one time I had four 250 GB to give me a TB for storage because at that time the 250 was the biggest drive available. This is not the case today however. Ideally (if you really need the drive space for storage) would be something like a good SATA 3 80GB or bigger Operating system drive, and a pair of 500 GB SATA drives in RAID 0 for your storage. Of course now drives are starting to show up at 1 TB. Plus I believe some of the Seagate drives now come with 3 to 5 year warranties.

Before you start with the playback check using another player, check to see if you are running BTV in Overlay or the Advanced 3d playback. Overlay should work fine. The 3d playback however is known to give you trouble with digital playback.

Let us know if the playback works better with a non-BTV player and we can go on from there.

[brianvlee]

Thanks for the suggestions so far--really good ideas that I hadn't thought of before.

bits--I will check on the bit-rate of the shows. That would actually make a lot of sense as to why some show recorded on the same station (negating signal issues) would not play as well as others.

Rich A--Yes, the RAID0 array is the only drive setup in my system, so the operating system is on that. With my previous system, I had three hard drives setup in spanned dynamic disks, with a 100gb partition for the OS and the rest for the BTV video folder. I never had problems with this setup, so I figured a RAID0 array with everything on it would be fine (as it would in theory be superior), but it could be there are issues with Windows files and BTV together as you say. I may see about adding a small SATA drive for the OS, but I will have to figure out if I can squeeze it in (my case technically only holds two HDs and they're obviously both in use).

I'm not at home right now to test anything, but I have tried playing the files in both Windows Media Player and VLC. WMP does the same choppiness BTV does. VLC, however, actually smooths the file. Instead of skipping the "bad" frames as BTV and WMP do, it actually makes the video a bit wavy. Kinda hard to explain, but for me it's actually quite preferable to the actually stopping of the action, and I've been using it to play all my questionable recordings since the switch. So I don't know if this helps to identify the problem, other than to say that BTV doesn't seem at fault since other players don't play the files back perfectly, though one does a better job than the other. This again leaves me to believe there is some imperfection in the recording itself, but I'm using the same tuner and antenna I used before in a flawless setup. Could be a driver issue I suppose. I think I will check the bitrate of the files as my first step to figuring this out.