Mpeg4 Recording

T

Turd Furguson

Limp Gawd
Joined
Oct 22, 2004
Messages
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I am possibly interested in recording some live mpeg4 streams. So what I am looking for a little bit of advice with is what time of hard drive horsepower I am going to need to keep up with recording this stuff. From what I have read, the stream(s) I would be uncompressed mpeg4. So I am sure I would need a RAID system or am I going overboard?

As of right now the CPU I have is a dual-core E2400 w/ 1gig memory.

I currently have a SATA Seagate 320gb 7200.10 drive but I swear this drive would get thrashed to death if I recorded live video streams to it.

Raptors will be out of the question as noise is a factor.

I am clueless on this folks.
 
mpeg4 is a compression algorithm, so 'uncompressed mpeg4' makes no sense. Where are you getting this 'mpeg4' source from? Generally mpeg4 is smaller than mpeg2, size wise, so i don't think you need anything special hard drive wise.
 
Need a little more info. What is your source? I believe DirecTV is broadcasting in MPEG4 now but there aren't any tuner cards that can directly capture their signal. How are you capturing it?

You don't need a super fast hard drive to record. Yours should be fine, but more info would make it easier to be sure about that.
 
I messed up with what I wrote with by saying uncompressed mpeg4.

I prefer not to say what source it is. ;)

Lets just say it is similar to a TV tuner card. But the only hardware acceleration would be coming from the offload to the video card.
 
mpeg4 doesn't even come into the picture really. What you need to know is what bitrate is your datastream that you have to record. We are guessing since its mpeg4, its relatively low. Knowing what device it is, would enable us to lookup what bitrate range it supports.

For comparison, broadcast hdtv is ~20megabit mpeg2. This is only 2 megabytes/second, which any hd ought to be able to do with ease.
 
Turd Furguson said:
I messed up with what I wrote with by saying uncompressed mpeg4.

I prefer not to say what source it is. ;)

Lets just say it is similar to a TV tuner card. But the only hardware acceleration would be coming from the offload to the video card.
Click to expand...

and why did my brain immediately go to a camcorder on a tripod in a livingroom?
 
Well, alright. Here's some generic info that may or may not provide an answer, then:

I'm not aware of any consumer-level tuner cards that can receive a signal broadcast with MPEG4 compression. Tuner cards that hardware encode can do so to MPEG/MPEG2. So if your source is connected to a tuner card (via S-Video, composite, or even component if you have one of those new Hauppauge boxes) you won't be capturing in MPEG4; you'll be making an MPEG/MPEG2 recording of the analog output of an MPEG4 stream. In this case it would be like recording anything else, and I think it safe to say that your system can handle recording in SD (though in the case of component input the bitrates would be much higher and potentially in HD).

If you have some kind of source input that is capable of interpreting the MPEG4 stream via a direct connection then, in theory, recording would just involve dumping the stream directly to your hard drive. This is like recording ATSC broadcasts, cards just dump the MPEG2 stream (around 20mbps) to the hard drive. So theoretically a card capable of receiving MPEG4 would do the same thing and you're fine unless your source has some ridiculous bitrate.

As for offload to the video card, that won't factor into it unless your recording software supports it... but I don't think the accelerated encoding is a feature that has been enabled in current video drivers? I'm not sure about this, anyone know one way or another? My impression was that it is certainly possible but no one is doing it yet.
 
if you are grabbing the stream directly, theres no encoding. The highest bitrate video streams i've heard of are the HD network feeds to their affiliates, which supposedly run at 45mbit, again - not a problem for any normal hard drive, its only 4.5mbyte/sec.
 
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