MPEG Capture Problems

[GeoPappas]

Hardware:
AMD 1.44-GHz 266-MHz FSB CPU
384 MB PC133 RAM
Sound card built into motherboard
Maxtor DiamondMax Plus Ultra DMA 40GB 7200 RPM hard disk (recently defragged)
1394a/Firewire PCI card
ATI Radeon 32MB DDR 4x AGP video card

Software:
Win XP SP1
DirectX 9.0b
NeroVision Express 2.0.1.14 (the latest release as of 11/07/2003)
Disabled anti-virus software
No other programs running

Situation:
I am trying to capture MPEG video from a digital video (DV) camera to my computer (thru Firewire). Eventually, I want to create a DVD. I installed NeroVision Express 2 (NE2) and have been playing with it.

NE2 provides a preview window where you can watch the video on your monitor. When I play the video through NE2, the CPU Usage (in Windows Task Manager) fluctuates between 22% and 37%.

When I capture video in AVI mode, the CPU Usage fluctuates between 9% and 23%. FYI: When capturing video in NE2, the preview of the video drops in resolution. I believe this is why CPU Usage drops when you capture video in AVI (rather than when you just play the video).

When I start capturing video in MPEG mode, after a few seconds, the CPU Usage gets pegged at 100%. This leads to a large amount of dropped frames and a very fragmented/choppy video.

Questions:
Is there a way to detect what part of the system (memory, sound card, video card, etc.) is being overloaded? Are there any programs available that can check for bottlenecks? For example, does anyone know if there is a program that can check the hard disk throughput? I thought that Nero had one, but I can't seem to find it.

What can I do to improve performance (besides buying a new computer)?

Where can I get the most bang for the buck?

How do I know what MPEG decoder my system is using? Would getting a better MPEG decoder help?

[theDruid]

Realtime MPEG encoding is very CPU-intensive.

You may find that you'd need a CPU upgrade to improve the performance.

I wouldn't really recommend using Nero to do the capturing; there are many other apps out there that would probably do a better job.

Most people (especially with slightly slower systems) find they get much better results with capturing to a less compressed format (e.g. HuffyUV or one of the MJPEG codecs).

You then need to re-encode the video later, but the system can do this 'at its own speed' - rather than having to try and keep up with the input from the capture.

There are many good alternatives in terms of encoders do it this way.

The main downside of this is that you need a lot of disc space to capture to a format like HuffyUV. Depending on what you want to capture (full length movies?) and what else you have on your hard disk (i.e. how much free space you have), 40gb will fill up pretty quickly.

I don't think you told us what OS you're running. For big captures, it's better to have an NTFS filesystem on your disks (which effectively has no limit on filesize). For this, you'd need WinXP or 2K. [edit - I see in your profile that you're running XP... do you have the disc formatted as NTFS?]

cheers,
mcdruid.

[bugster]

@theDruid, he is capturing DV, so Huffy etc don't come into.

@GeoPappas, other than the stuff about codecs (only applies to analog caps really), do what theDruid suggests. Capture to avi and encode later. You can even use Nero to encode, though its not the best quality output by a long way.

DV avi is still pretty big though, ~13Gb per hour, so you still want a fair amount of disk space.

If you really want to encode mpeg on the fly, get a faster CPU, much faster.

[FulciLives]

The best approach quality wise is to capture DV AVI and then use a software MPEG-2 encoder such as TMPGEnc or CINEMA CRAFT ENCODER (aka CCE SP or CCE BASIC).

If you still want to capture direct to MPEG-2 then you will need to upgrade your computer since it obviously is not fast enough (as mentioned direct MPEG-2 capture is very CPU intensive).

The cheapest way to upgrade would be to buy a HARDWARE MPEG-2 encoding device such as the Hauppauge WinTV PVR-250 which can be bought for around $150 (sometimes less on eBay).

This is a PCI capture card that has hareware MPEG-2 encoding so it doesn't tax the computer's CPU meaning it should work fine with your system. It only does MPEG-1/MPEG-2 but from what people say of it (and I've seen sample clips) it works rather well.

- John "FulciLives" Coleman

[Leoslocks]

I am in a similar boat and sinking fast. I believe my computer is speced out in the button above my post.

I have lots of disk space but the Raid 0 array that W2K (NTFS) is on is the only drive fast enough to capture AVI without dropping frames. It took 25 gig to store the 70 minutes of Svhs tape I captured.

Refering to AVI Capture:
First off, I upgraded an AMD XP1600 to an XP2400. Little improvement in dropped frames.

Installing the Via Latency patch did wonders but still issues.

Adjusting the Virtual Memory to a fixed size may have cured the bulk of the problems.

Using just two memory sticks (Slot 1 and 3) in the Soyo KT333 board cured memory related issues.

I can capture AVI but using Nero6 to create a DVD from the captured AVI produces nothing but crap. I understand that improvements are due in December. I am considering purchasing TMPGEnc but that adds more to the learning curve.

Still, there is good advice available here and I am learning in spite of my stubborn resolve to make Nero work.

[GeoPappas]

Capture to avi and encode later.

I am new to this stuff, but my understanding is that MPEG is a higher quality than AVI. Is this true? If so, then if I captured to AVI and then converted to MPEG later, wouldn't I end up with a lower quality DVD?

If you really want to encode mpeg on the fly, get a faster CPU, much faster.

What would you consider to be the minimum CPU speed to capture MPEG from DV?

From my experience, I have rarely seen a CPU upgrade fix something. I have found that there is usually a bottleneck somewhere else (hard disk speed, video card performance, sound card performance, etc.) that needs to be fixed.

Is there any way to check for performance bottlenecks?

[GeoPappas]

I wouldn't really recommend using Nero to do the capturing; there are many other apps out there that would probably do a better job.

From reading some of the posts on this board, I got the impression that the software used to capture DV to MPEG was not as significant (in terms of performance) as the hardware. Would using another software app to capture DV to MPEG make that much of a difference? If so, what software would you recommend?

do you have the disc formatted as NTFS?

Yes, I have NTFS partitions.

[FulciLives]

OK first of all you got some things wrong. When you "capture" from your digital cam to your computer using the FIREWIRE port you are just making a direct copy of data. The VIDEO is already digital in the cam (on the tape) so the "capture" is more of a digital data copy. There is no loss.

The benefit of this is that DV AVI is very easy to edit whereas MPEG-2 is not so easy to edit.

When you are done doing any editing you then use a software program for the MPEG-2 conversion. If done correctly this will look very good. In fact it will look better than a straight real time MPEG-2 capture ESPECIALLY when using "low" bitrates. The reason for this is software can do a true multi-pass VBR encode which gives overall better quality when you use a bitrate lower than 8000kbps which we pretty much all do since 8000kbps only gives you about an hour or so per disc.

The only drawback to the DV AVI to MPEG-2 via software method is that it can take a long time. On your computer a 2 hour 2-pass VBR would probably take (I'm guessing) at least 8 to 12 hours or more.

As far as MPEG-2 direct capture ... this is dependent mostly on CPU speed. All you need is a decent video card (nothing special) and a decent speed HDD (100 ATA 7200 is common now and works just fine). So the speed factor in MPEG-2 encoding basically boils down to CPU and if you want to do it competely with SOFTWARE you will need at least a 2.0 CPU or faster for full D1 720x480 NTSC 29.970fps capture (same applies to PAL which is 720x576 25.000 fps).

However you can get around the CPU issue if you buy the aforementioned WinTV PVR-250 which uses HARDWARE MPEG-2 encoding. It has special hardware that is designed specifically for MPEG-1/MPEG-2 real time encoding. Thus it can be used with any reasonable speed computer (I'm sure it would be fine with your computer specs).

- John "FulciLives" Coleman

[theDruid]

... my understanding is that MPEG is a higher quality than AVI. Is this true?

No, this is not true. You can't really say that one is higher quality than the other. MPEG covers several different types of video file - MPEG-1 (VCD), MPEG-2 (SVCD/DVD), MPEG-4 etc.. AVI, on the other hand is just the 'wrapper' Windows uses for many video codecs. An avi can use a variety of different codecs, from DivX to DV via all sorts of others.

The benefit wth your set-up of capturing to AVI (DV) first, is that this format is less compressed, and your system can 'keep up' with the capture without dropping frames.

Capturing straight to MPEG in this case means capturing to a more compressed format. Therefore, the computer has to do a lot of number crunching to reduce the amount of data it in the output.

MPEG encoding is very CPU intensive. In other applications, I agree, bottlenecks are more often RAM etc.. but with video encoding, it's the CPU.

This is reflected by the fact that your CPU is 'maxing out' at 100% and starting to drop frames.

You'll find with MPEG encoding 'offline' (i.e. after capturing to AVI) will max out your CPU too - except it may run slower than realtime (e.g. taking more than 1hr to encode 1hr of video). That shows that the system simply couldn't keep up in realtime.

Your RAM could maybe do with a small upgrade - many people are starting to see 512mb as the minimum you should go for.

However, I doubt you would find this would improve performance for video much. The CPU really is the most important component for this.

cheers,
mcdruid.

[bugster]

However you can get around the CPU issue if you buy the aforementioned WinTV PVR-250 which uses HARDWARE MPEG-2 encoding. It has special hardware that is designed specifically for MPEG-1/MPEG-2 real time encoding. Thus it can be used with any reasonable speed computer (I'm sure it would be fine with your computer specs).

- John "FulciLives" Coleman

Correct me if I am wrong, but isn't that an analog capture card, and so no use for DV capture?

[courtrrb]

I do all my video capture (Windvr3) right to svcd or dvd across a network to a linux box with no droped frames at all. I'am running a Athlon 1.4ghz with a 3,9G hd running WinXP(A spare pc). I do all video editing and authoring under linux. The DVD's I've been making from my Vhs tapes look as good and no worse than the tape themselves. So you can get relativity good quality without using large amounts of disk space or a superfast cpu.

[FulciLives]

However you can get around the CPU issue if you buy the aforementioned WinTV PVR-250 which uses HARDWARE MPEG-2 encoding. It has special hardware that is designed specifically for MPEG-1/MPEG-2 real time encoding. Thus it can be used with any reasonable speed computer (I'm sure it would be fine with your computer specs).

- John "FulciLives" Coleman

Correct me if I am wrong, but isn't that an analog capture card, and so no use for DV capture?

This card has analog video (composite and S-Video) inputs and analog stereo (RCA Left/Right) inputs. This card does not have a DV in port.

However I suggested it because I think it is a good solution for MPEG-1/MPEG-2 capture since it uses HARDWARE MPEG-1/MPEG-2 REAL-TIME encoding thus putting very little drain on the computer's CPU.

Obviously from the comments the user made plus knowing the specs of the computer ... this computer appears to not be FAST enough to do real-time software only MPEG-2 encoding. The WinTV PVR-250 is a good solution that is much cheaper than upgrading to a faster CPU as that would probably require a new motherboard, new RAM memory probably, etc.

All Digital Camcorders have analog Video/Audio out and encoding this output direct to MPEG-2 will give results as good as using a DV in port. I have read user comments on those that have stand alone DVD recorders that have DV in and they can't see a the difference in the final MPEG-2 DVD when using DV in VS the analog inputs when the source is from a Digital Camcorder.

So the fact that the WinTV PVR-350 only has analog inputs seems to not be of a great concern ... especially considering any other alternative would be rather much more expensive.

- John "FulciLives" Coleman

[GeoPappas]

I suggested it because I think it is a good solution for MPEG-1/MPEG-2 capture since it uses HARDWARE MPEG-1/MPEG-2 REAL-TIME encoding thus putting very little drain on the computer's CPU.

I'm not sure I totally understand.

Are you saying that I can connect the DV camera via RCA cables to the WinTV PVR-250 card (which would then use the onboard hardware MPEG encoder) to transfer to MPEG?

or,

Are you saying that I can connect the DV camera via the 1394a/Firewire card and the computer would then automatically use the hardware MPEG encoder on the WinTV PVR-250 card (instead of software MPEG codec) to transfer to MPEG?

[FulciLives]

I suggested it because I think it is a good solution for MPEG-1/MPEG-2 capture since it uses HARDWARE MPEG-1/MPEG-2 REAL-TIME encoding thus putting very little drain on the computer's CPU.

I'm not sure I totally understand.

Are you saying that I can connect the DV camera via RCA cables to the WinTV PVR-250 card (which would then use the onboard hardware MPEG encoder) to transfer to MPEG?

or,

Are you saying that I can connect the DV camera via the 1394a/Firewire card and the computer would then automatically use the hardware MPEG encoder on the WinTV PVR-250 card (instead of software MPEG codec) to transfer to MPEG?

I'm saying you hook up the analog video/audio outputs of your camcorder to the WinTV PVR-250 and it will use it's specially designed hardware to do your MPEG-2 encoding thus putting little drain on the computer's CPU.

Your camcorder is digital so the analog output will be of extremely high quality as will the conversion to MPEG-2 using the WinTV PVR-250 so I wouldn't worry about not using the DV/FIREWIRE port.

Of course you can just use the DV/FIREWIRE port on the computer to do AVI and then use TMPGEnc or CCE etc. to do a software MPEG-2 encode but this will take a lot longer and it sounds as if you want to do direct MPEG-2 captures. This is where the WinTV PVR-250 comes into play.

There is nothing wrong with capturing to AVI first then doing a software MPEG-2 encode ... in fact this will probably give you even better quality since you can do a true 2-pass VBR but it does take a long time and I am simply trying to tell you one way you can do it in REAL TIME using equipment that is inexpensive (the WinTV PVR-250) that will work with your current system while providing very good quality.

In short your computer cannot do software MPEG-2 capture as it is too slow and the WinTV PVR-250 is your cheapest path of upgrading to doing real time MPEG-2 capturing.

- John "FulciLives" Coleman