Compression & Capturing question

[tehinternet]

I'm new to capturing and am attempting to capture 1080i over HDMI from a cable box to H.264 MP4 video. While I would love to capture in 1080, currently I'm limiting myself to 720p due to filesize problems. Typically I would be recording 2 hour, 50 minute video. Right now I'm using the no frills Aver MeciaCenter software which came with my HDMI capture card.

My problem is my videos are weighing in at about 14 GB for 2 hrs, 50 min (or about 80MB/minute).

Problem 1:
For my existing videos I would like to compress them down to a filesize more reasonably sizes for long term storage as I will have many of these videos. Is going from 14 GB to say 3-5 GB for 2:50 720p video while retaining a reasonable amount a quality feasible? If so, how would I go about it? If not, why?

Problem 2:
For future recording, if possible I'd like to directly record them at a lower filesize without the need to compress it later.
I simply am not familiar with things like audio and video bitrates, etc and what could produce good quality without getting too large or how to balance bitrates between the audio and vision portions
In Aver Media Center I basically have these options:

Option [Default] (other possible settings)
Format [H.264]
Level [Automatic] (levels 1 to 5.1 are possible)
Video Size: Using 720, but would like to use 1080 if even possible
Entropy Mode: [CAVLC] (CABAC also possible)
Video Bitrate [12000 kbps] (100 to 15000 possible)
Audio Sample Rate [48000] (32000 and 44100 are other options)
Audio Bitrate per channel [160 kbps] (can select 48 to 192 kbps)

I have tried adjusting the Level to only 3.1 which supposedly would allow me to record at 1280×720@30.0. I've also tried dropping the video bitrate down to about 7000kbps, Audio Sample rate to 44100, and Audio bitrate down to 128kbps, but that didn't really change much for me. With that I get down to about 50-60 MB/Minute instead of the default 80 MB/Minute, but if the goal is a 4GB video I think I need to try and get to 25MB/Minute. What changes would you recommend to preserve quality as much as possible while getting the size down?

Thanks!

[Cornucopia]

#1 3-5GB for 2:50. 2:50 = 170minutes = 10200 seconds. 3GB= 3072MB = 24576Mb. 24576/10200 = 2.4Mbps. That is somewhat low for even SD quality at MPEG2. I would expect it to be TOO low for 720p, even using h.264/AVC, but maybe you will find it acceptable. Who knows?

#2 Totally depends on what software you are using. I am not familiar with AVER MediaCenter's capabilities (nor do I even intend to be), but I wouldn't be surprised if it DID NOT give you the options you desired.

I think you need to reassess your goal. 3Mbps is not usually considered to be good quality by most people here. WHY is that the goal?

What I'm surprised about is that you haven't mentioned anything yet about having problems with HDCP. I would have thought that would be the first item on the list.

Scott

[jagabo]

my videos are weighing in at about 14 GB for 2 hrs... (I want) 3-5 GB

file size = bitrate * running time

So if you want a file 1/3 the size use 1/3 the bitrate. Whether the quality will be acceptable or not depends on the nature of the video, the compression settings used, and what you can tolerate.