What capture bitrate for HD?

[radioouman]

First of all, I have an ATI TV Wonder 650. This has hardware MPEG encoding. (By the way, I really like this card!)

When I capture using the "best" recording setting with BeyondTV, the quality is noticable worse when I play it back. So I did a little searching and found that BeyondTV's best mode is 7800 kbps, but full quality HD signals are around 19400 kbps. I created a new quality setting for 19400 kbps, but I wonder if this is necessary.

What are you guys using? I guess that I was hoping to just capture the exact signal over the air without any compression. Is there any way to do that?

[Deuce911]

Originally Posted by radioouman

First of all, I have an ATI TV Wonder 650. This has hardware MPEG encoding. (By the way, I really like this card!)

When I capture using the "best" recording setting with BeyondTV, the quality is noticable worse when I play it back. So I did a little searching and found that BeyondTV's best mode is 7800 kbps, but full quality HD signals are around 19400 kbps. I created a new quality setting for 19400 kbps, but I wonder if this is necessary.

What are you guys using? I guess that I was hoping to just capture the exact signal over the air without any compression. Is there any way to do that?

OTA HD is already a Digital Stream and a HD Tuner just captures the exact stream that is transmitted from the TV Station, you do not capture a certain Bitrate.

Mike

[radioouman]

That's what I was thinking, but when I play back my recordings, there are many more mpeg artifacts than when viewing the stream over the air.

[tscales]

I'd say it is a signal problem. Even the best HD tuners, and the 650 is one of the best, don't seem to tune in OTA as well as a TV. Do you have a good amplifier on the antenna? It requires an amplified antenna.

Tom

[radioouman]

The signal is perfect. I never have any places where there is skipped audio or blocks missing from losing the signal. This is all about additional MPEG artifacts. I can see that what I play back have more MPEG compression artifacts than when I'm watching it live over the air on my PC. (I'm not even comparing this to another TV.)

[tscales]

Well, you're at the absolute bottom end of the 'required power'. HD, according the Snapstream, requires an Athlon 1.7, so you Sempron is under the cutoff. Your symptoms don't sound like that, since you can play Live TV.

What about your hard drive? IDE/SATA, Cache, 7200rpm?

Have you looked at CPU utilization when playing back? Playback is MUCH harder on your system then recording.

Tom

[enigma9o7]

There shouldn't be any difference watching from livetv and recorded shows (unless the recorded shows were showsqueezed). Watching livetv or recorded shows does the EXACT same thing for HD... plays back the mpeg-2 transport stream directly from the hard drive. So if you're noticing a difference, you're imagining it.

[radioouman]

Live TV doesn't display in an overlay?

Playing video back isn't choppy at all. Very smooth. Around 60% CPU utilization while playing video back.
Unless there is something in the MPEG playback driver that prioritizes smoothness over quality, I've never seen an MPEG play like this when the system couldn't keep up. Usually it gets choppy. However on my system, it is perfectly smooth other than some blockiness as if I had encoded my MPEG videos at a lower bitrate.

I do have the NVidia Purevideo driver installed.

[Bigbird999]

The macroblocks could be a symptom of a weak digital signal. Ie they are recorded into the ts stream that you recorded. I think the ota cards require a slightly stronger signal than a HD TV tuner or a cable STB.

BB

[mlomker]

Originally Posted by radioouman

I can see that what I play back have more MPEG compression artifacts than when I'm watching it live over the air on my PC. (I'm not even comparing this to another TV.)

I'd recommend downloading a copy of VideoReDo (they have a demo and the link is in my sig). You can use it to scroll through the file and see if the quality of the individual frames compares well to your playback.

I was lazy and just bought a faster processor to solve the same problem in my setup. It's quite possible that there's a code issue and you'll have to decide if your time or your money is more valuable. I've never had much fiscal sense and *love* excuses for new hardware.