Success!!...No dropped frames/excellent quality with ATI Radeon video capture - AVS Forum
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post #1 of 13 Old 05-23-2001, 06:47 PM - Thread Starter
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I have finally succeeded in creating a usable Tivo replacement using the ATI AIW Radeon and ATI's MMC 7.1 software with the Gemstar TV guide. The major problem was surmounting the famous (infamous?) dropped frames problem that numerous board members (including me) have been experiencing with the ATI MPEG encoder used with the ATI MMC. After much searching through various forums including this one, I decided on the following equipment:

Motherboard: ASUS P4T
CPU: Intel P4 1.5Ghz
Memory: 256 PC800 RIMM
Video: ATI AIW Radeon (3102 driver)
Sound: Creative Soundblaster X-Gamer
Storage: IBM 75GXP 75gig hard drive
OS: Win2k SP2

With this "power" setup I am able to do MPEG capture at 720x480, IBP frames, 10Mbit/s, full motion estimation(99), full motion search settings (256 horizontal, 128 vertical) with NO dropped frames!!!. I've done no tweaking whatsoever to achieve this result, just standard installs of all of the software. CPU utilization is at around 75% during capture.

For the justification for this setup I used the following factors which affect MPEG capture:

1) MPEG encoder settings. Seems obvious but the higher the parameter settings are pushed, the more likely you are to exceed your computer's resources thus resulting in dropped frames. However my requirement was that I should be able to max out all settings and still have no dropped frames. Therefore this wasn't a factor I was willing to compromise on. For my purposes I wanted to be able to support MPEG capture settings of 720x480, IBP frames, 8-10 Mbit data rate, full motion estimation(99), full motion estimation search ranges (256 horizontal, 128 vertical), CD quality sound. Pretty tall order, eh?

2) CPU power. Another obvious one. Better MPEG2 capture requires more horsepower. For my settings it appeared I needed at least a 1 - 1.2 Ghz CPU to handle the load based on the empirical data I was able to gather from the experiences of others. Just to be safe I decided to get 1.5Ghz to give myself a little headroom.

3) RAM bandwidth. No matter how fast the CPU is, if the memory bandwidth cannot handle the enormous amounts of data being shuttled through it for the motion estimation calculations then dropped frames will result. Regular SDRAM doesn't seem to cut it. DDR might but I didn't want to take any chances so I chose Rambus which supports a 3.2gig/s transfer rate (theoretical)

4) Disk speed. Actually this doesn't seem to matter that much. It appears that pretty much any ATA66 and above drives can handle the load. MPEG in general doesn't produce the gobs of data that AVIs generate so most drives have no problem keeping up.

5) OS. Yes the OS does appear to make a difference. Using a similar setup to my hardware above, I installed a friend's computer with win98 instead of win2k and he got dropped frames!!! (astonishing given the P4 1.5Ghz and the Rambus memory!!). Therefore win2k seems to be a better OS for video capture than win98. I must mention that my friend had 128mb of memory instead of my 256mb but given that I never noticed memory consumption above 90mb on my machine I dismissed this as a factor.

Additional comments:
Make sure that you install SP2 if you're going to be doing video capture with ATIs MMC. I was having intermittent crashing problems until I installed SP2.

Win2k breaks the 4gb barrier (if you install NTFS) allowing video capture up to the available space of your hard drive. No need to worry about capturing those long movies anymore.

In addition to excellent video capture, the Tivo functionality of the MMC works very well in my setup. I can pause and rewind Live TV without any of the intermittent crashes I was experiencing under win98

Here's something wierd...Win2k reports my video, sound and network cards to be all on IRQ9 yet this has had no effect on my capture. This calls into question the conventional wisdom of having cards on separate IRQs?

Well, its back to having fun with my setup!

Cheers
Lester

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Website: http://www.digicasa.com
"The shortest answer is doing"
English Proverb. Collected in: George Herbert, Jacula Prudentum (1651).

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Website: http://www.digicasa.com
"The shortest answer is doing"
English Proverb. Collected in: George Herbert, Jacula Prudentum (1651).
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post #2 of 13 Old 05-23-2001, 10:36 PM
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The PCI spec supports IRQ sharing. There may have been some buggy drivers that didn't implement it well, but IRQ sharing works fine for me.

If you think about it, for any system that has only one CPU, there's no inherent reason for not sharing IRQs if the hardware implements priority correctly and the software is carefully written by people who know what they are doing.
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post #3 of 13 Old 05-24-2001, 11:09 AM
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Okay, so I'll be obnoxious and post this here as well...

Lester,

With that dream system do you use CBR or VBR?

And with that bitrate of 10Mbit/sec, how large a file is a one hour show? (I get 3.9Gigs/hr with 7.2Mbit I frame with the AIW, versus 2.35Gigs/hr using my Sigma DVR, which I think is doing 4.5Mbit IBP, VBR, but I'm not sure of the max and average bitrate)

My PIII-800E does not have the juice to do this, so I do I frame only with the AIW. But I'll still have this card even when the next generation comes out, so it'll be nice to know its abilities will scale since its software driven.

I'd like to get my system to a point where I could keep these MPG2 recordings, but the AIW files are just not good enough yet on my current setup. Have you used the VBR at all? I tried with my current system, setting everything down to a rate that wouldn't drop frames, and every time it would make a VBR file the AIW could play it back fine but it would freak out my Hollywood Plus or my DVR. I frame files play fine. This is new to MMC7.1 as far as I can tell. Do you only play your files on this dream machine that makes them?

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post #4 of 13 Old 05-24-2001, 11:15 AM
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For those of us with "legacy" hardware, I've been getting excellent results with much less horsepower:

Motherboard: ASUS P3BF
CPU: Intel P3-750
Memory: 128MB SDRAM
Video: ATI AIW Radeon (3102 driver)
Sound: Creative Soundblaster Live! Value
Storage: WD 80gig 5400rpm drive, NTFS
Controller: Promise Ultra ATA-66
OS: Win2k
ATI MMC v.7.0

The settings I use are MPEG-2, 480x480, I-frames only, 8Mbps, full motion estimation(99), CD quality sound. I record several shows a week, each lasting one hour(~4GB). PQ is quite good (VHS quality) with no dropped frames. I also watch or record HD programs using my Hipix at the same time, to the same partition, also with no dropped frames. CPU usage is about 65%. If I do something that is CPU intensive, like switching from ATSC to NTSC modes on the Hipix, it will very quickly start to drop a few frames.

I actually had to throttle down from 10Mbps to 8Mbps to reduce file size, since even though I was using NTFS, MMC would fail to complete the recording correctly if the filesize exceeded 4GB.

When I tried to upgrade to v7.1 of MMC, I first upgraded to DX8.0a and ran the DirectX DV update as well. I got all sorts of errors, even blue-screens! So I rolled back to MMC 7.0. I wonder if W2K's SP2 would fix this.

Having the capability to watch/record two shows at a time, with one of them being HD, has made me a very happy HTPC user!
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post #5 of 13 Old 05-24-2001, 11:36 AM
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Could the same be accomplished using a 1.3GHz Athlon with DDR memory? Is it time for an upgrade http://www.avsforum.com/ubb/biggrin.gif Is there a place where I can download win2K SP2 directly? I cant seem to pull it down from the mircosoft site.



[This message has been edited by Vasim Pathan (edited 05-24-2001).]
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post #6 of 13 Old 05-24-2001, 11:46 AM - Thread Starter
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Mance,

For my "regular" TV recordings I actually use 480x480, IBP at 2.33Mbps (VBR) (My idea is to later dump these to CD as SVCDs when I run out of space). This allows me to have lots of TV shows online. 2.33Mbps may sound low but since I am using IBP frames and VBR I can fit a lot more quality into 2.33Mbps. It is probably the same as or better quality than your 7.2 Mbit. What resolution do you capture at? One trick is to lower the resolution if you don't have lots of spare CPU power since this allows the encoder to pack more quality in since it does not have to store the extra resolution bits.

I use the higher recording rates when I want to preserve high quality on certain special shows. I only play back the files on this machine. I use this machine as my only TV/DVD/VCR/CD/MP3 Jukebox player in the apartment.

hindif,

I did get errors with MMC 7.1 before the SP2 patch. That patch got rid of all of my errors.


Cheers
Lester

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Website: http://www.digicasa.com
"The shortest answer is doing"
English Proverb. Collected in: George Herbert, Jacula Prudentum (1651).

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Website: http://www.digicasa.com
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post #7 of 13 Old 05-24-2001, 12:58 PM
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For the record I also use MMC7.1 with whatever the new official release drivers were that came out at the same time (I'm in Win98SE with DX8 and the DV patch and the 4.1 DVD player, even though I don't have a DVDrom drive on this machine). Much better stability, but image quality has suffered on my 'legacy machine'. That's why I'm very curious about Lester's dream system and am pondering an upgrade.


hindif,

I also do two things at once, but not two captures. I'll often watch an MPG2 off my shared hard drive over the LAN to the Hollywood+ machine in the family room while the AIW is capturing a TV show to the same hard drive locally. No problems at all. One of the benefits of heavily compressed video I guess.

Lester,

Someone else posted here a couple of weeks ago how to get the best quality recording using a machine of my era, P3-800E, and he also suggested 480x480 IBP, but was doing 8Mb/s at first and then recommended 6Mb/s. I tried both of those and dropped frames (14% on 8mb and 10% on 6Mb).

I normally do the Full profile (I think that's what it's called), which is 720x480 and just manually change it to I frame as a custom profile, but that was the only change. I had problems with reading these files with my H+ when I tried to do fancy stuff, not to mention dropped frames, but I can't recall if that was the IPB or the VBR that the H+ choked on. When I set it to I frame only I not only didn't drop any more frames, naturally, but my H+ could play them again. I'll have to check that IPB/VBR thing again. And I'll go back and try lowering the res again and see how that affects PQ. You're probably right about lowering the res decreasing the workload, makes sense.

For me it really seems like it's the bitrate that's the biggest factor for picture quality. IBP and VBR not only don't work for me, unless I set the bitrate down so low as to be unacceptable, but they also didn't seem to save my any file size either, which I thought was weird.

I'm sure I'd be able to get by with SVCD bitrates if I had a faster processor. Right now I'm not satisfied enough with my I frame captures to want to keep them even at high bitrates. There's too much flicker for my taste, which didn't seem to be there in MMC7.0.

hindif's ~4G/hr file size for 8Mb/s captures jives with my 3.9G/hr 7.2Mb/s captures. Lester, what size files do you get for an hour at 10Mb/s with IBP and VBR?

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post #8 of 13 Old 05-24-2001, 01:21 PM - Thread Starter
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Mance,

VBR and IBP do not necessarily affect the filesize given a fixed bit rate. What these parameters allow you to do is to reduce the bitrate without affecting quality. For instance, suppose you have a given bitrate say 10mbit/s, and you capture at 640x480. With I frames only you are fitting separate compressed 640x480 frames into your bitrate. With IBP frames the B and P frames can be more highly compressed since they reference the I frame. Thus for a given bitrate you can fit much more information with IBP than with I frames only. Therefore you can reduce your bitrate to 5mbit/s (just an example) and retain the quality of 10mbit/s I frame only.

VBR has a similar story. Some frames are easier to compress than others. With CBR all (I) frames are compressed the same whereas with VBR simple I frames get more compression and complex I frames get less compression. Therefore the encoder uses the given bit rate as a guide and may go higher on the bit rate for complex frames and lower on the bitrate for simple frames but the average bit rate will probably be close to the one you specified resulting in negligible difference in filesize. However, since you are using VBR you can lower the average bit rate and still retain the same quality since the encoder will go higher for complex frames anyway.

Therefore to make a long story short, if you use VBR and IBP you can set your bitrate a lot lower and maintain the same quality which is tantamount to reducing the final filesize.

However VBR and especially IBP requires gobs of CPU power for the calculations. Hence my choice of the 1.5Ghz P4 so as to get high quality captures at fairly low bitrates.

And yes, lowering the res will definitely help. The less bits the CPU has to handle, the less demanding are the VBR and IBP calculations. It sounds counterintuitive but you might want to try even 352x480 as your capture size and then use IBP and VBR with motion estimation and search ranges maxed and see if you still drop frames. If you're still dropping frames then cut back on the motion estimation a bit. You may be surprised at the quality of the captures you get.

Cheers
Lester

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Website: http://www.digicasa.com
"The shortest answer is doing"
English Proverb. Collected in: George Herbert, Jacula Prudentum (1651).

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Website: http://www.digicasa.com
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post #9 of 13 Old 05-24-2001, 02:14 PM
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Thanks, I'll try and give several different custom profiles a try tonight when I get home and report back on the success or failures.

That was my understanding of VBR and IPB as well, but thanks for the refresher. What threw me off was a couple of weeks ago when I was trying a forum member's suggestion to use 352x480 IPB at 8 and 6mb/s I went through several combinations and IPB and I framed captures for a given bitrate and res seemed to have identical file sizes. I started thinking that maybe the ATI software wasn't implementing them right.

I'll give them another go and see what happens.

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post #10 of 13 Old 05-25-2001, 11:16 AM
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well, I tried again upgrading the MMC software from 7.0 to 7.1, and after running the DX8.0a, DV for DX, and SP2 updates, I'm still getting errors! When I go the the "Schedule" tab of the TV setup screen, MMC crashes every time. I also have been getting blue screen errors as well since upgrading. My guess is that the MMC is somehow conflicting with my Hipix. Anyone here using both MMC 7.1 and the Hipix (2.3) without problems?
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post #11 of 13 Old 05-25-2001, 02:27 PM
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I was wondering the same thing so I gave it a shot. My main system (not my htpc) specs are as follows:

FIC AD11
AMD T-bird 1.33
512MB PC2100
W2K SP2
Radeon 64 VIVO
2 40gb Quantum Fireball AS
Promise Fasttrack 100 configured in Raid 0

Under the video capture applet I maxed _everything_ out.
Settings were as follows:
720x480
MPEG2
44/16/Stereo
Deinterlacing Checked along with Visual Masking
4:2
Constant Bit Rate
15 MB/S
Motion estimation: 100
256 Horizontal 128 Vertical

BTW what is visual masking?

Anyway end result it captured perfectly. If I tried doing anything else it would display "<1% dropped frames" Setting it to 10mb/s alleviates this.

Finally I captured a minute worth of video and it came to 117mb, does this sound right? Because at 15mb/s of just video equals 900mb, am I missing something?


Quote:
Originally posted by Vasim Pathan:
Could the same be accomplished using a 1.3GHz Athlon with DDR memory? Is it time for an upgrade http://www.avsforum.com/ubb/biggrin.gif Is there a place where I can download win2K SP2 directly? I cant seem to pull it down from the mircosoft site.

[This message has been edited by Vasim Pathan (edited 05-24-2001).]
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post #12 of 13 Old 05-25-2001, 02:47 PM - Thread Starter
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hindif,

If you are trying to upgrade to MMC7.1 over MMC7.0 then perhaps this is the problem. Have you tried completely removing all traces of 7.0 (including registry settings) then installing 7.1 "clean"?

Cheers
Lester

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Lester Jacobs
Website: http://www.digicasa.com
"The shortest answer is doing"
English Proverb. Collected in: George Herbert, Jacula Prudentum (1651).

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Website: http://www.digicasa.com
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post #13 of 13 Old 05-25-2001, 09:30 PM
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yes, I was trying to upgrade 7.1 from 7.0 (after uninstalling 7.0). I too think this might have been the culprit as I did a fresh install of Windows 2000 today and so far so good with 7.1!
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