Capturing video

[mike20021969]

I have a Sagem DVB freeview reciever with USB out port - for transferring recordings to (example) an external hard drive.
The bit rate for these videos is 4,500kbps.

I also have an AverMedia USB freeview reciever which plugs directly into a USB port on my laptop - the video is recorded directly onto the laptop's HDD at around 3,000kbps.

For convenience more than anything, I use a TerraTec Grabster AV400 USB capture box. I capture video at 7,000kbps using S-video option.

My question is this: why is the AverMedia 3,000kbps video superior than the Grabster capturing at 7,000kbps? (To get anywhere near the quality - and still not achieving it - I have to record at 7,000kbps - going more doesn't improve things. Incidentally, recording at 3,000kbps on the Grabster is awful). The detail within the AverMedia 3,000kbps video is excellent compared to my Grabster.

How can this be? How do they (AverMedia) achieve this?

[mariush]

Better integrated chips, more powerful chips mean better quality settings can be used and so on...

[mike20021969]

Are there any USB capture devices which could achieve similar results? I have tried a Pinnacle and ADSTech USB capture device (both much cheaper than the Grabster) and the results are practically identical to the Grabster.
Thanks.

[Ghitulescu]

It's simply a hardware encoders competition: your crappy Grabster vs. a studio one. You paid probably 50$, they paid more than 2000$ (but multi-stream encoders might reach easily 15000$ in the entry class). A multi-stream encoder is an encoder that takes 2 or more videos and compress them in real-time in order to fit the transmission channel (for instance all channels on a transponder are simultaneously encoded, or as bouquets).

In order to have the results studios have, you probably need to spend a little more ... it was always like that, only the "ignorants" (that's a very mild term :p) can believe they pay 19.99$ for an USB-grabber and obtain Hollywood-like quality, as the package says.

There's only one situation when you can obtain a better quality "the analog way" - the double reconversion (D/A->A/D) might soften the image a bit, and the "blocking" is no longer seen. You need however a very good MPEG-2 hardware encoder.

The best solution is to capture uncompressed with a good card then let a good encoder do its job (like CCE or HC).

But in the end the quality is just a matter of personal experience, expectation and awareness.

[mike20021969]

your crappy Grabster vs. a studio one. You paid probably 50$, they paid more than 2000$ (but multi-stream encoders might reach easily 15000$ in the entry class)

The Grabster cost me £89 in the UK. The quality I'm after (ie AverMedia at 3,000kbps) cost me £60.
Who are 'they' you are referring too?
I think you misunderstand what I'm asking.

An AverMedia £60 USB Freeview reciever recording directly onto my laptop hard drive at 3,000kbps gives superior quality than my £89 Grabster at 7,000kbps.
However AverMedia achieves this cost no more than £60 for whatever is in there little box of tricks.
So what USB capture can achieve this for around the same money?

[Ghitulescu]

I answered your question. None in your budget.

What you have with your FreeView receiver is a digital copy (1:1) of a video stream encoded by TV stations with a hardware encoder. So when you compare 7Mbps of grabster with 3Mbps of freeview, you see the price difference. Anyway, 3Mbps is very low.

I don't understand why you want to capture the analog out of the freeview receiver, but anyway, get a nice good old capture card, capture uncompressed and encode it later on.

PS: they are the TV stations ;) if you read the whole sentence

[mike20021969]

What you have with your FreeView receiver is a digital copy (1:1) of a video stream encoded by TV stations with a hardware encoder. So when you compare 7Mbps of grabster with 3Mbps of freeview, you see the price difference. Anyway, 3Mbps is very low.



Right, I understand that. Sorry, I was under the impression the AverMedia was doing the encoding and misunderstood what you originally said.
Thanks :)

[Ghitulescu]

Just to make sure: There's no good consumer grade card that features a hardware MPEG-2 encoder, most of them are simply awful. The bad news is that most of them cannot be disabled, so you're forced to capture directly in MPEG-2 anyway. Semiprofi cards (like DV500, DV2000) either allow you to disable the onboard MPEG-2 encoder (DV500) or feature a better hardware codec (eg M-JPEG).

So the recommended capture setup here at doom9 seems to be: uncompressed video, cleaning/editing in avisynth (or similar), encoding in CCE/HC (or x264 if you prefer H.264). Capturing directly in MPEG is unanimously to be avoided, at least with consumer grade cards.

[lordsmurf]

60-90 quid is pennies for high-end devices. That barely covers sales tax or shipping.

Capturing in MPEG is fine, depending on the device. MPEG is a big format too. Certain usage will outperform DV, for example, although you'll pay with it in file size. (I-frame only, 25MB/s, custom matrix, etc). The $25 MPEG cards and $100 DVD recorders, as found in consumer stores like Walmart or Best Buy, are the bad MPEG recorders.