S-Video vs. Firewire

[patrickjos]

I have an Adaptec Videoh! (external USB) card. It has an S-Video socket for video in. I need to convert 4 Mini-DV tapes to MPEG2.

Should I expect reasonably good quality if I go from a Canon camcorder to the Videoh card with Real-time encode to MPEG2, or should I be thinking about doing it thru firewire (ie. is the quality going to be very noticeable -firewire vs. s-video) with a realtime-encode firewire card such as Hauppage WinTV-PVR-250. I just have this one-time conversion to do; the camcorder isn't mine -it's borrowed.

Patrick

[sitlet]

USE THE FIREWIRE. thats the whole point of having a minidv camcorder. if you use the s-video to your capture card, the camcorder is converting the signal to analog, then that capture card is converting it back to digital. thats a waste, and will result in a much worse quality picture. use the firewire.

[Richard_G]

File transfer using Firewire is just that. An absolute copy of what is on the DV tape is transferred to your hard drive as a data stream.

By comparison, capturing using S-Video, or any other analogue method for that matter, involves turning the digital data on the DV tape into an analogue video signal, passing it to your computer by whatever connection method you choose, using a compression codec to compress the video signal and digitising it again to save it back to the hard drive as data.

Which do you think would have the best quality?

[patrickjos]

Slight correction to this post...

I just realized that the Hauppage card does not have a firewire input ...It has S-Video input. So it's back to the drawing board on this one...

Patrick

I have an Adaptec Videoh! (external USB) card. It has an S-Video socket for video in. I need to convert 4 Mini-DV tapes to MPEG2.

Should I expect reasonably good quality if I go from a Canon camcorder to the Videoh card with Real-time encode to MPEG2, or should I be thinking about doing it thru firewire (ie. is the quality going to be very noticeable -firewire vs. s-video) with a realtime-encode firewire card such as Hauppage WinTV-PVR-250. I just have this one-time conversion to do; the camcorder isn't mine -it's borrowed.

Patrick

[davideck]

I will probably get flamed for this, but I will claim that it depends upon the relative quality of the hardware vs. software encoders. I have tried this experiment by first tranferring from my MiniDV camcorder via firewire and encoding with Sonic's MyDVD. Then I recorded the same segment via s-video into a PVR-250. The video quality from the PVR-250 was clearly superior to that from MyDVD. I have also seen 1394 encodes using Roxio and Pinnacle products, and IMHO the PVR-250 beats them as well. The real time encoding is an added bonus. I have no experience with TMPGEnc; perhaps it can outperform the PVR-250.

[patrickjos]

So in other words, you're saying that you've done the direct comparison and found the quality of the hardware encoded MPEG2 to be high even when the input is through S-Video ...correct?

I realize that THEORETICALLY firewire should be better and for the most demanding situations firewire is certainly the way to go but I'm really looking for input from people like you who have done an apples-to-apples comparison. Thanks for the input.

Of course, a true apples-to-apples comparison would require that the software MPEG2 encoding settings be exactly the same as the hardware encoder uses -so that the only difference would be the S-Video vs. firewire input - or in the case of hardware encoders the comparison would have to be between two hardware encoders where one uses s-video input and the other uses firewire input - but your report is still helpful.

Patrick

I will probably get flamed for this, but I will claim that it depends upon the relative quality of the hardware vs. software encoders. I have tried this experiment by first tranferring from my MiniDV camcorder via firewire and encoding with Sonic's MyDVD. Then I recorded the same segment via s-video into a PVR-250. The video quality from the PVR-250 was clearly superior to that from MyDVD. I have also seen 1394 encodes using Roxio and Pinnacle products, and IMHO the PVR-250 beats them as well. The real time encoding is an added bonus. I have no experience with TMPGEnc; perhaps it can outperform the PVR-250.

[beamguy]

Slight correction to this post...

I just realized that the Hauppage card does not have a firewire input ...It has S-Video input. So it's back to the drawing board on this one...

Patrick

Firewire is simply an upgraded serial connection like USB, ethernet, or even like your old serial input/output that is rapidly disappearing from PCs and already disappeared from Mac's. It has nothing to do with video, but digital video cameras do use it, hard drives use it, cd-writers use it...
IEEE 1394 is another name for the same thing. "Firewire" is simply a brand name. Here is a link to a controller that will read this in, cost $14.
http://www.newegg.com/app/ViewProductDesc.asp?description=15-102-009&depa=1
After installation you will need software to talk to your camera, likely it came with the camera but be sure to download the latest version from the companie's website.

[patrickjos]

Yes, I'm aware of all this. I had been thinking of using the Videoh or Hauppage cards because their hardware encoders drop an mpeg onto my harddrive which is a tiny fraction of the size of the huge ".avi" file that a small $15-$35 fireware card drops on my Drive (I'm working with several hours of video).

However, last night I tried capturing directly from the camcorder through the analog video inputs of the Videoh card and i feel there's definitely a noticeable drop in quality.

So now it's looking like a second Huge harddrive with a firewire card and software encoding might be the only realistic option.

Patrick

Slight correction to this post...
I just realized that the Hauppage card does not have a firewire input ...It has S-Video input. So it's back to the drawing board on this one...
Patrick

Firewire is simply an upgraded serial connection like USB, ethernet, or even like your old serial input/output that is rapidly disappearing from PCs and already disappeared from Mac's. It has nothing to do with video, but digital video cameras do use it, hard drives use it, cd-writers use it...
IEEE 1394 is another name for the same thing. "Firewire" is simply a brand name. Here is a link to a controller that will read this in, cost $14.
http://www.newegg.com/app/ViewProductDesc.asp?description=15-102-009&depa=1
After installation you will need software to talk to your camera, likely it came with the camera but be sure to download the latest version from the companie's website.

[Richard_G]

I realize that THEORETICALLY firewire should be better and for the most demanding situations firewire is certainly the way to go but I'm really looking for input from people like you who have done an apples-to-apples comparison. Thanks for the input.

Not theoretically, but actually. A Firewire transfer is just that - a file transfer. What ends up on your hard drive is absolutely bit for bit identical to the data on your miniDV tape.

You may be able to get good quality video using an analogue S-Video capture, and, as it will be altered, some may consider that it can actually LOOK better. But it never can be the same as the original.

Firewire transfer is so simple, doesn't require any specialist hardware and just works. It must be, thousands of US citizens on this site are managing to do it!

[epo]

Best quality is Firewire+TMPGenc. Same visual quality (much simpler and faster though) on TV (through analog input!) is S-VIDEO to PVR-250. But PVR needs high bitrates (6000+ avg.) to give excellent results. Otherwise it will give lots of block noise.

[davideck]

Richard_G -

I agree that transferring data from a MiniDV Camcorder over 1394 to an .avi file is a lossless process. But the "quality" issue is a function of the compression of that .avi file into an mpeg-2 file. Are you claiming that any software encoder that compresses an .avi file into an mpeg-2 file will outperform any hardware encoder that compresses an s-video input into an mpeg-2 file?

patrickjos -

I tried the Videoh PCI card and IMHO the PVR-250 card provides superior results. I have no experience with the Videoh USB version.

[beamguy]

Yes, I'm aware of all this. I had been thinking of using the Videoh or Hauppage cards because their hardware encoders drop an mpeg onto my harddrive which is a tiny fraction of the size of the huge ".avi" file that a small $15-$35 fireware card drops on my Drive

Assuming your camera capture in Mpeg2 even a couple hours of video is only of order 10 Gbytes. Just read it in, then use the free program virtualdub to compact it to any format you want. DivX with MP3 is a logical choice, and will take of order 1Gbyte/hour.

[MrMungus]

I have an Adaptec Videoh! (external USB) card. It has an S-Video socket for video in. I need to convert 4 Mini-DV tapes to MPEG2.

Should I expect reasonably good quality if I go from a Canon camcorder to the Videoh card with Real-time encode to MPEG2, or should I be thinking about doing it thru firewire (ie. is the quality going to be very noticeable -firewire vs. s-video) with a realtime-encode firewire card such as Hauppage WinTV-PVR-250. I just have this one-time conversion to do; the camcorder isn't mine -it's borrowed.

Patrick

The quality difference will not be noticable and you'll save a ton of time by not having to convert from AVI to MPEG-2.

[MrMungus]

Yes, I'm aware of all this. I had been thinking of using the Videoh or Hauppage cards because their hardware encoders drop an mpeg onto my harddrive which is a tiny fraction of the size of the huge ".avi" file that a small $15-$35 fireware card drops on my Drive (I'm working with several hours of video).

However, last night I tried capturing directly from the camcorder through the analog video inputs of the Videoh card and i feel there's definitely a noticeable drop in quality.

So now it's looking like a second Huge harddrive with a firewire card and software encoding might be the only realistic option.

Patrick

Slight correction to this post...
I just realized that the Hauppage card does not have a firewire input ...It has S-Video input. So it's back to the drawing board on this one...
Patrick

Firewire is simply an upgraded serial connection like USB, ethernet, or even like your old serial input/output that is rapidly disappearing from PCs and already disappeared from Mac's. It has nothing to do with video, but digital video cameras do use it, hard drives use it, cd-writers use it...
IEEE 1394 is another name for the same thing. "Firewire" is simply a brand name. Here is a link to a controller that will read this in, cost $14.
http://www.newegg.com/app/ViewProductDesc.asp?description=15-102-009&depa=1
After installation you will need software to talk to your camera, likely it came with the camera but be sure to download the latest version from the companie's website.

Did you try the PVR-250? The thing about the Videoh card is that I don't think you can adjust the settings other than "Better, Best" whatever. The PVR-250 gives you full control. My caps from VHS tape have been spectacular (and, again, you'll save a LOT of time and headache).

[Richard_G]

Richard_G -

I agree that transferring data from a MiniDV Camcorder over 1394 to an .avi file is a lossless process. But the "quality" issue is a function of the compression of that .avi file into an mpeg-2 file. Are you claiming that any software encoder that compresses an .avi file into an mpeg-2 file will outperform any hardware encoder that compresses an s-video input into an mpeg-2 file?

I'm not claiming that at all. As you say, Firewire to avi will be lossless and give perfect quality (or identical to the original, I've seen some originals that are far from perfect!). If you then convert it to mpeg, I agree that this is where the compression and degradation takes place. I very much doubt there would be any difference in the quality between hardware and software encoding if you used identical mpeg settings.

The difference is that if you are starting with a source that is digital (DV), converting it to an analogue S-Video signal and capturing it before encoding it to mpeg (whether using hardware or software) it cannot possibly be as good as something that has only been converted once instead of twice ie. DV avi to mpeg.

[davideck]

Richard G -

Are you saying that any software encoder that compresses a 1394 source into an mpeg-2 file will outperform any hardware encoder that compresses a 1394 source first converted to an s-video source into an mpeg-2 file?

I believe that converting MiniDV to s-video and then resampling actually provides a pre-filtering operation that helps the mpeg encoding process. The s-video output of my MiniDV camcorder looks fantastic; very stable, noise free, and most likely filtered in the analog domain to remove any sampling artifacts. It therefore represents a best case source for an analog input hardware encoder.

I would expect that this same type of pre filtering would be beneficial in the digital domain for a firewire input.

Perhaps this analog path reduces the high frequency content of the original signal. Not enough to be noticeable, but enough to remove sharp edges and high frequency detail that demands a higher bitrate from the encoder.

When I encoded via 1394 there were lots of tiny digital dots in the picture, especially around anything that moved. When I encoded via the analog path, these dots were not present. Perhaps the picture was not as sharp, but much more appealing to the eye in my opinion...

[Richard_G]

Davideck

You said it in the last sentence, it looks better to your eye. Any mpeg encoder, hardware or software, will show the same artifacts if the bitrate is too low. As you say, sharp edges and fast movement need very high bitrates to not be noticable as pixelation. Encoding a IEEE 1394 transferred file will need a higher bitrate because the original is that much sharper. If the original is softened slightly, you can get away with lower bitrates for a similar looking end result. As you say though, they might not be quite as sharp.

At the end of the day, it's down to how much compression you can get away with before it starts to look rough. With an analogue source which has already been degraded, you can probably get away with slightly more.

Different peoples idea of what looks right varies anyway. Most people have the colour turned up too high on their TV set so what they watch isn't natural (put your hand next to the TV screen and see if the newscasters face is the same colour as your hand, it won't be), but it is how they want it to look. It's no different to everyone turning the bass and treble up on their Hi-Fi. The sound isn't how the artist wanted it to sound but it's how the listener wants to hear it.

An encoded Firewire transfer (assuming the bitrate is high enough) will be more accurate to the original. Whether it looks better than one that has already been altered slightly before encoding is purely a matter of taste.

[davideck]

Richard G -

I agree with everything in your last post. I have been assuming a comparison between 1394 and analog encodes given the same bitrate for both. My argument is that it cannot be assumed that a 1394 software encode will "look better" than an analog capture/hardware encode for any given bitrate, particulary if a minimal bitrate is also desired.

[Richard_G]

It sounds like we are both saying the same thing but looking at it from a different viewpoint. The quality of the original will most certainly have quite a bearing if you are looking at minimal bitrates, with a deliberately 'softened' original looking better. For most of the stuff I do I always use a constant bitrate. For DV files that are going onto DVDR, I leave the framesize at 720 x 576 (PAL) and use a CBR of no less than 6500kbs. This gives me just over and hour and a half on a DVDR. If it is for transferred camcorder tapes, I use 8000kbs to give an hour (which is a complete camcorder tapes worth).

If I need more than this per DVDR, rather than compressing even more (and ending up with more artifacts than picture), I drop the framesize to 1/2 D1 (352 x 576) and use a bitrate of no less than 3500kbs. This will give me about 3 hours per disk with a marginally softened appearance but still no artifacts.

[patrickjos]

Just wanted to post a little update here...

I tried using the "Videoh" capture card (analog capture from DV camcorder with realtime encode to mpeg). The quality was definitely inferior -visible drop in quality- ...so I went and got a firewire card (adaptec also).

Patrick