Dave Carrigan said: > "Paul McHale" <[EMAIL PROTECTED]> writes: > >> I know the Tivo doesn't have much horse power. They are case in >> point for a design which is just fast enough. They appeared to >> have spared every expense. It is an awesome unit. Just saying, I >> don't think they have a 600MHz processor ... Could be completely >> wrong.
> As you can see, it is a 54MHz PowerPC chip with 16MB of memory; not > a powerhouse by any means. it is a powerhorse when it comes to video capture though. i have a tivo and i also do a ton of video capture from it(i haven't hacked it, not going to touch the insides of it until tivo goes under and i dont have any other choice). i have a 1.3ghz athlon with wintv pci and 768MB ram with a dual 20GB raid0 array. tivo can easily encode in ~640x480(approx what NTSC is). wintv on my athlon struggles to encode at 320x240. infact i make it a point NOT to move my mouse cursor when capturing otherwise it will drop frames. CPU isn't really a factor as the cpu hovers between 15-45%. just the slightest movement of the mouse and it drops a frameor 2. its a very fragile setup, i restart X frequently and i disable opengl in my nvidia drivers when i want to capture, and re enable it when i want to play unreal tournament. otherwise it drops more frames. I/O is not a limitation either, the video is encoded at a compression level that drops the bitrate to ~90kbyte/second. so adding a 50-disk raid0 array wont do anything. so if you want to build a tivo-like device oneof the main things is a good video capture card. im not personally aware of any that can do mpeg2 or better under linux in hardware, i believe mpeg2 is what tivo uses. you can probably find a card that can do mpeg1 but they will be pricey i expect ~$1000 range. but then the task is finding the software for it. most likely you'll want a command line app that can stop/start recording so you can control it from remote and from utilities like crontab and at. but if you do mpeg1, you'll average ~620MB/hour of video.. if you can live with video at 320x240 then a wintv card is fine. personally i watch my 320x240 video on my 19" monitor scaled to 1600x1200 and the quality is QUITE good. im not sure how it would look on my TV though(~1987 tv). all my recordings on tivo are done in the lowest quality setting. wintv card is also rock solid stable. the only video capture app ive used seriosuly sofar is qtvidcap from the avifile package(dont know if its debianized). i encode all of my stuff into DiVx 4.0, drop the sound quality to as low as it can go and it drops the size of the video dramatically. currently i average about 350MB/hour of video with divx 4. it used to be in the range of 700MB/hour with older divx and higher sound quality. ive looked at a ton of other capture apps evne a couple commercial ones but none offered the compression i wanted(to save space mainly, i have a couple hundred hours of saved video). and qtvidcap is the only app im aware of that can do Divx4. its by no means a great app, it crashes if your not careful, it drops frames if your not careful, it behaves weird if your not careful. it can be difficult to tune..but its all i got. nate
