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Linux Based Media Boxes?
Matt Dugan returns an old question to the forefront: "I am building a Linux-based 'media box', which will sit alongside the TV, Stereo, VCR, etc.. My goals are to play DVD's, MP3s/Oggs, CD's, VCD's, and the occasional Divx AVI. Though DVD support isn't perfect, I expect it to be well on it's way by the time I get everything set up and running the way I want, but my problem lies here: I want to be able to do 'real-time' video capture to an IBM Desktar 60GXP 30GB drive via a Pinnacle DC10+ MJPEG PCI card. Has anyone else successfully configured such a beast?"
"Here are the system specs:
- Socket 7 MB with onboard Video/Audio, ATA-66/33 IDE
- AMD K6-III/400MHz processor
- 128MB PC100
- Fujitsu 6.4GB primary HD
- IBM Deskstar 60GXP 30.7GB secondary (in removeable 5.25" caddy)
- Pioneer 10x/40x DVD-ROM
- Generic 24x CD-ROM
- Pinnacle DC10+ Video Capture Card
- RealTek 10/100 NIC
I would prefer to run Vector Linux, for the smaller footprint (gives me more space for Music on my primary HD) but I am open to suggestions. Also, what video cards give the highest quality TV-out under Linux?"
Why do you want this thing to do DVD? Honestly. I'm looking into doing something very similar, and all I can say is components, components, components.
You probably don't want to have a system switch duty between mp3 and video capture, and DVD playback from a PC will be inferior to a DVD component most of the time as well (not to mention vastly inferior sound quality on a system with onboard sound). Don't use the DVD drive, get a DVD player. Consider getting a separate PC to do mp3 playback (maybe a used laptop; low heat, low noise, small footprint, and anything over 150MHz can handle mp3 without a sweat), but don't necessarily restrict yourself to mp3s on a local hard drive - NFS isn't a bottleneck when you're playing mp3s.
NFS probably is a bottleneck on video capture; stick with a local hard drive, or consider cacheing data to local disk and copying it over to a file server at your leisure (I would guess that video playback would not be restrained by NFS).
Do you really want a network cable (or two, if you follow my suggestion) running from your stereo/TV to a hub? Consider wireless. Have you already considered and/or dealt with the amount of noise a PC makes? Take a look at Quiet PC to silence your hard drive, power supply, CPU fans, and case fans.
This would result in a setup something like:
- TV
- stereo (preferably surround-sound capable
:)
- VCR
- DVD player
- computer audio player/recorder system (say... P200 laptop with wireless card)
- computer video player/recorder system (basically the system you describe - with silenced or silent moving parts, and a wireless card)
- file server, with lots of reasonably capable storage (SCSI-2 would probably do fine, if we're otherwise talking about a 10-11Mb/s network and no performance-sensitive writing like video feeds)
- wireless access point
Of course, this system involves a lot of components, and the price adds up. But, you can work your way up... a fileserver is an immediate win, wireless is an immediate win, a DVD player is an immediate win, a video player/recorder is an immediate win that improves once you have wireless, an Ogg/mp3 component is an immediate win once you've got wireless (and improves with a file server).In addition, you've got a lot of components that you can upgrade independantly, tune for their own purpose, or sell (if that dot.com you're working for goes under).
--Matthew
It captures MPEG-1 fine, but anything with a decent resolution/framerate is useless. MPEG-2 requires a Pentium III 500 MINIMUM. (I happen to have a P3/500 - but I woul dlike to be able to do something during capture).
We need either a dedicated DSP for encoding (codec for Mpeg2 and mpeg4 would then be possible) or just an MPEG-2 encoder.
MPEG-4 would be a good choice for such a beast though as the file sizes are quite small and the video quality is quite good for most things.
Also, DVD playback on ATI cards suck. I have a Creative Labs MPEG-2 decoder card and DVD drive, they worked flawlessly on my Pentium 133 a few years ago, and continue to work good on my Pentium III/500.
(ATI recommends DMA to get good enough performance from their card, funny it wasn't necessary on my Pentium 133, even if I was browsing the net, etc.).
Sorry for the rant.
I have an Iomega Buz card that works great for capturing MJPEG video under linux. Low-to-No CPU usage, full-screen, full-frame PAL.
I would normally lean towards using half-frame (352x288 PAL) capturing as it consumes less disk space (1-2MB/s) than the 2-5MB/s of 720x576.
My soundcard, however, can't do mmapped recording and is no good for synched audio capturing. This screws me royally till i get round to putting a new soundcard in the machine.
I have had a BT848 TV Tuner card in the same machine, and that worked great for fullscreen TV playback at 800x600, also with low to no CPU usage.
My original foray into this field was with the BT848 in a P-200 box. I used it as a TV, an MP3 jukebox and an internet terminal displaying on my TV.
This was connected to the TV via an external scan converter, and let me watch TV in a window, while i surfed the net/played MP3s etc.
Remote control was taken care of by a home-built IR adapter and LIRC, and later an analog IR 'joypad' which came with the scan converter. and worked as a serial mouse.
Fonts and stuff needed major tweaking, and the general usability of a standard X desktop on a TV is bad.
With regard to the DC10/Buz:
I am not sure whether it is possible to capture MJPEG to a file, and play it back at the same time. Theoretically, since the bytes are on the disk, this should be easy, but you never know.
MJPEG will also consume vast amounts of disk space. realtime transcoding to MPEG or even DivX would be nice - piping the MJPEG through an encoder instead of writing to disk, but the encoders i have used aren't fast enough (though my machine is slowish - a dual P.Pro 200 that lacks MMX), but may be an option with good hardware.
An MJPEG-based PVR would be the best first step to take, but be aware that MJPEG consumes at least twice as much space as MPEG, so budget for big disks. However quality should be really good.
The stability of lavtools (MJPEG capture/playback utils) has been good for me so far, but i haven't used them in a PVR-like capacity - i.e heavy use with a failure in capturing being somewhat unnacceptable.
When i get a new soundcard for my box, i will be looking at doing this again, perhaps what we need is a sourceforge project or similar 'hub' for MJPEG-based PVR projects.
I gots ta ding a ding dang my dang a long ling long
As for the video capturing, here are a few places to start:
Video for Linux resources
Video for Linux mailing list - archives