PC power for SD viewing

[avg1joe]

I've read a bit about what the recommended specs are for a htpc. I currently have a twinhan 1020a for satellite and a "instant hdtv pci" that I haven't tried yet. I have a radeon 9550 256mb agp with s-video out.

I want to pick up nbc on 103w and look for other unlisted hd channels, record them and watch them later on an old tube style sdtv.

I've read that you need around a 5000+ or e2200 cpu or better to watch high definition at 1080. I understand this is flexible depending on your video card.

Let's say that I want to record a hd broadcast and play it back later on my sd tv. Do I actually need a decent dual core and a newer video card to play hd at this lower resolution? If not, what specs would I need.

 

[brentb636]

I think you'll be fine as far as recording the stream on your slower pc. But the decoding of the stream for playback is going to take just as much horsepower, whether you are going to a SD TV or a HDTV . Decoding that h.264 HD stream is the power hungry monster. I wouldn't expect you could get by with a low powered pc, hoping that it would only have to decode "part of " the stream , just enough to fill an SD TV.

[edit] As an experiment I recorded some PBS HD ( 18Mbps) into an mpg file. Then I played it back on my desktop ( Not my HDTVPC) , an Athlon 2800+, 2 GB ram, several years old.
My desktop played it back just fine, but ran at about 90% cpu utilization. This is on a non h.264 stream . Had I streamed a h.264 HD video into an mpg file, I expect that my desktop wouldn't have handled it. Not much left after 90% is cooking. [/edit]

 

[avg1joe]

Ok, thank you for checking.

 

[Larry1]

You could re-incode the stream to a lower resolution that would play fine on a low end pc. The re-incode process may take a long time due to the low power of the pc.

 

[avg1joe]

What program(s) would I use to do that? Is that a built in feature of any of the software I'd already need?

 

[Larry1]

It's been quite a while since I have re-encoded anything. Mainly use VideoReDo now and do not re-encode anymore, (although it will re-encode as well) as all my recordings at the moment are only SD and not HD. Try VideoReDo to see if it will work for you. It has a free trial, but be warned, once you try it you WILL end up buying it.

 

[gillham]

What program(s) would I use to do that? Is that a built in feature of any of the software I'd already need?

You can use 'vlc' to re-encode, but it is slightly complicated. It is free and can also stream something across the network.

 

[B.J.]

As mentioned above, I've also played PBS HD on my 1.9 GHz computer, and it just barely worked (and has since stopped working since my computer is getting bogged down with services). But I can't come close to playing the high bitrate network HD on the computer. Low bitrate HD, such as the stuff that used to be FTA on the Anik E2 sat played easily. I forgot what the bitrate of that was, but it was on a 9000 SR mux. Also, the NASA HD, plays easily on the computer. All these examples are 1080i, so the ability to play HD depends as much on the bitrate than the resolution.

Re re-encoding, I agree re VLC being a bit complicated, but it does seem to be quite capable. I've re-encoded a couple things with VLC, but never completely understood what I was doing. I eventually just bought VideoReDo, and eventually upgraded to their Suite. I really like VideoReDo, however I have a question for anyone who is experienced with it.

Related, but a bit off topic, I wanted to take a recorded file, and convert it into a smaller file with VideoReDo, so that I could send it over the internet. I had assumed that if I reduced the bitrate, that it would decrease the size of the recorded file, however this does not seem to be the case to any significant extent. I've cut the bitrate more than in half, and it only reduces the file size by about 2%. Seems like the only way I can reduce the file size is to cut back the resolution. This doesn't seem logical to me, since you see sat feeds with greatly different SRs all giving video of the same screen dimensions. For example, if I record a football game of a high speed network 1080i feed, it creates about a 50 GB file, but a medium speed 1080i OTA broadcast only takes about 20 GB, and it would seem that the only difference would be the bitrate. But with VideoReDo, for some reason changing the bitrate just doesn't seem to affect the size of the file.
Anyway, why doesn't VideoReDo reduce the file size when you re-encode at a lower bitrate???

 

[Anole]

Anyway, why doesn't VideoReDo reduce the file size when you re-encode at a lower bitrate???

I suggest you ask that question on the VideoReDo Forum.
Probably in the section: VideoReDo TVSuite - Support