Some questions before choosing a capture card

[WiKiDAngel]

First of all, I want to mention that I have read the FAQ, and some other posts on this forum and tried to get as much information as I can from them. Yet, some issues still remain unanswered and this is why I'm bringing them up here. Hope you guys could answer atleast some of them.

These questions are about buying a capture card. I need such a card for several purposes, one of them is to transfer VHS tapes into DVDs without any loss of quality(is that even practicle?). I might want to edit them in the process too and I suppose that it's possible.

Here are some questions I still couldn't find an answer for:

1. One of main reasons I want to transfer VHS tapes into DVD Discs is that VHS tapes lose quality in time and even get unusuable. Until not long ago I thought that DVD Discs can last forever, but recently I heard that it's not true and they even last less than VHS tapes. Is that correct? many of these VHS tapes hold home movies I want to save for decades.

2. There are so many different brands of Capture cards. On the surface it seems they have similar attributes, but their prices are way different and I assume that so is their quality. Could you gimme some names of reliable manufactors and brands? maybe point me to the 'better' stuff? or tell me how to determine what's good and what's not by myself?

3. From reading reviews and articles, I concluded that I can only use the software bundle that comes with my card, is that true? I assume there are other special tools (like adobe premiere) that are better and more configureable than the given software - won't I be able to use them instead?

4. What is better - a hardware encoder on the capture card or a software encoder? so many capture cards have hardware encoders, but could someone explain why they are better than software? software encoders get updated, and are more configurable - doesn't that makes them better? I realise that on software encoders my cpu will have to do all the work but what's so bad about that?

5. I know there is lossless compression and lossy compression - does each capture card use different method of compression? and is it even possible to work with lossless compression? because the quality will be better that way I assume.

6. through the FAQ I got to some article that talks about choosing Capturing Hardware. They talked about different brands of capture cards - some that do real time editing and some that don't. correct me if I'm wrong but I thought the process of capturing is always done in real time on all cards - could anyone explain this matter to me?

7. last small question - some cards have "Hardware decoding" option - I know what's hardware encoding, but what does decoding does?


Hope you could answer some of those questions for me - it would help me a lot.

Thanks in advance,
Guy.

[mrlipring]

Originally posted by WiKiDAngel
[B]First of all, I want to mention that I have read the FAQ, and some other posts on this forum and tried to get as much information as I can from them. Yet, some issues still remain unanswered and this is why I'm bringing them up here. Hope you guys could answer atleast some of them.

These questions are about buying a capture card. I need such a card for several purposes, one of them is to transfer VHS tapes into DVDs without any loss of quality(is that even practicle?). I might want to edit them in the process too and I suppose that it's possible.

it's vert practical, and makes sense, yep. you can fit hours and hours on a dvdr, and it's not all that hard to do. might take a while if you're gonna run filters etc, but yeah, go for it.

Here are some questions I still couldn't find an answer for:

1. One of main reasons I want to transfer VHS tapes into DVD Discs is that VHS tapes lose quality in time and even get unusuable. Until not long ago I thought that DVD Discs can last forever, but recently I heard that it's not true and they even last less than VHS tapes. Is that correct? many of these VHS tapes hold home movies I want to save for decades.

dvdrs ain't really been around long enough for anyone to reliably say how long they last. one definite advantage i can think of there is that if it's something important, it's only a matter of minutes to make a 1:1 copy of a dvdr, unlike a copy of a vhs which'll take ages, and you'll lose quality. if you use good quality media, you should be fine for years. i'd happily transfer stuff to dvd and bin the tapes.

2. There are so many different brands of Capture cards. On the surface it seems they have similar attributes, but their prices are way different and I assume that so is their quality. Could you gimme some names of reliable manufactors and brands? maybe point me to the 'better' stuff? or tell me how to determine what's good and what's not by myself?

depends what you need, and what you want to do. do you want to cap directly to mpeg1/2 or not? there are a load of other questions people here can ask you about capping though, i know a bit but i'm no expert.

3. From reading reviews and articles, I concluded that I can only use the software bundle that comes with my card, is that true? I assume there are other special tools (like adobe premiere) that are better and more configureable than the given software - won't I be able to use them instead?

depends on the card really. :) i wouldn't get one that locked me into using one package to capture, personally.

[/quote]4. What is better - a hardware encoder on the capture card or a software encoder? so many capture cards have hardware encoders, but could someone explain why they are better than software? software encoders get updated, and are more configurable - doesn't that makes them better? I realise that on software encoders my cpu will have to do all the work but what's so bad about that?[/quote]

there's a thread about this somewhere, i believe. i prefer to capture to lossless (or as near to it as is possible - very high bitrate divx is my preference) avi, at pal dvd resolution. that way you can run your filters etc. i wouldn't like to capture directly to mpeg-2. i'd rather convert my edited/filtered avi to mpeg1/2/4 afterwards.

5. I know there is lossless compression and lossy compression - does each capture card use different method of compression? and is it even possible to work with lossless compression? because the quality will be better that way I assume.

lossless is best, because it's just that - lossless. it DOES take up far more disc space though. most capture cards will allow you to capture to whatever codec you want, lossless or lossy.

6. through the FAQ I got to some article that talks about choosing Capturing Hardware. They talked about different brands of capture cards - some that do real time editing and some that don't. correct me if I'm wrong but I thought the process of capturing is always done in real time on all cards - could anyone explain this matter to me?

they're talking about realtime *editing*, not capturing.

7. last small question - some cards have "Hardware decoding" option - I know what's hardware encoding, but what does decoding does?

just that, i'd imagine. it decodes with hardware, not software, so when viewing/editing video, it'll use hardware to display the video.

[LeonMcNichol]

Originally posted by mrlipring
Here are some questions I still couldn't find an answer for:

1. One of main reasons I want to transfer VHS tapes into DVD Discs is that VHS tapes lose quality in time and even get unusuable. Until not long ago I thought that DVD Discs can last forever, but recently I heard that it's not true and they even last less than VHS tapes. Is that correct? many of these VHS tapes hold home movies I want to save for decades.


dvdrs ain't really been around long enough for anyone to reliably say how long they last. one definite advantage i can think of there is that if it's something important, it's only a matter of minutes to make a 1:1 copy of a dvdr, unlike a copy of a vhs which'll take ages, and you'll lose quality. if you use good quality media, you should be fine for years. i'd happily transfer stuff to dvd and bin the tapes.


Yes, some of the more cheepo discs have been proven to die if placed in damp drawers and such within a month even, but the high end good quality media do quite well. So don't buy cheep brand CD-Rs/DVD-Rs or use RW since those are litterally etched into the metal and not imprinted into ink. Like professional DVD/CDs are.

[WiKiDAngel]

First of all thanks for the answers. They've cleared up some issues, but I still have some stuff I don't fully understand.

1. You said that a GOOD DVD-R media will last for some time. question is for how long? if it's 5-10 years then that's still not enough. Many movies are important home movies and memories. I wouldn't want to try and watch one in a few years and to find out that it's not working.
Are there any safer storage media than DVD-R? and I don't mean about CD-Rs or DVD-Rs... I mean in general.

2. About encoding format - I heard that encoding directly to MPEG makes it hard and almost impossible to edit the captured film. Question is what do you guys mean by editing? I never captured myself so I dunno how much editing I will have to do - could anyone explain some cases when I'll be using editing that can't be done on MPEG 1/2/4 formats?

3. I searched this forum for a thread about Hardware Encoders VS Software Encoders - didn't find anything besides a very small thread that doesn't explain much. Could anyone give a link to that thread?

4. About real time editing - as I've seen these cards's prices increase significally - Is that a function I need? how is it helpful?

5. About quality - In the whole capturing process will there be some loss of quality between the source VHS and the DVD result? or can I keep the exact same quality as the VHS source on the DVD target? I assume that better it won't be since quality can never increase - only decrease.

Thanks again for your help!

Guy.

[trevlac]

Originally posted by WiKiDAngel
5. About quality - In the whole capturing process will there be some loss of quality between the source VHS and the DVD result? or can I keep the exact same quality as the VHS source on the DVD target? I assume that better it won't be since quality can never increase - only decrease.


You are mixing 'Information/data' & 'quality' just a little.

VHS & DVD are storage medium for information, using certain standards. It is possible to transfer analog to digital and not loose information. However, going from VHS to DVD does loose some information. This is because MPEG2 on DVD compresses the sampled digital information. The more you compress the more you loose. Vertical color is the bigest looser here. This is not a big deal because what you care about is quality (or resolution).

Back to quality: A high enough capture frame, mpeg bit rate, and mpeg frame should cover the maximum resolution VHS contains. I'd say the numbers for this are 704 capture, 352 resize, 3Mbit should cover you. If you are going direcly to Mpeg, and you do not have a BT8x8 card, you might just cap at 352. This all depends upon all of the points in between VHS-->DVD. There can be many.

Finally, I'd like to address the 'bold' statement in your quote. One can never increase information. One can increase quality. Removing bad things increases quality. Removing may/may not reduce resolution. It is all a balance depnding upon the video source, and desired payback equipment (aka TV or PC)

Some examples:

1) You have a herringbone pattern in a TV channel due to FM interference. Adding an "FM Trap" filter to the cable will remove info from the signal. If the interference is removed from the picture, the quality went up. Digital filters (in an editor) do the same type of thing.

2) You have interlaced source and want to watch it on a progressive screen. Throw away 1/2 the lines and you can watch it. Keep them and you would not want to. Quality up, resolution down, info down.

[jggimi]

2. About encoding format - I heard that encoding directly to MPEG makes it hard and almost impossible to edit the captured film. Question is what do you guys mean by editing? I never captured myself so I dunno how much editing I will have to do - could anyone explain some cases when I'll be using editing that can't be done on MPEG 1/2/4 formats?MPEG uses a technique called "Group of Pictures" (GOP) for encoding. A group starts with a "keyframe," which contains enough information to display the entire image. Think of a keyframe as you would any single image file on your computer. Subsequent frames only contain changes. This saves a lot of space, as you can imagine. Keyframes are also called intra frames, or I-frames. The frames that contain changes are either predictive (P-frames) or bidirectional (B-frames), depending on how they are created.

Editing a capture video usually includes setting the appropriate start and end points, and when needed, excising advertisements or other program breaks. When the capture is MPEG, and the editing is done in MPEG, those edits can only take place at keyframes.

MPEG codecs are also lossy. This means that not only are they compressing images, but, the entire image was not saved to begin with. Think about still pictures on your computer for a moment. For example, images saved in .bmp or .tif formats are [/i]lossless[i]. Every pixel is stored. But images saved in .jpg format are lossy. You can often save in .jpg with several different choices of quality, and decide how much is lost. If your editing includes re-encoding MPEG->MPEG, you introduce additional loss.

When I used to capture in MPEG-2, I set every frame to be a keyframe. I did this initially because it consumed less CPU than any other GOP setting, but it also gave me more flexibility when editing. But my editing process quickly moved to frameserving with AviSynth. Since frameserving produces an uncompressed video stream, the GOP settings do not matter. Frameserving can either be done with AviSynth or with an older technology known as VFAPI.

But I eventually moved from MPEG-2 to HuffYUV capture, which is a lossless codec, and I did that primarily to eliminate dropped frames when capturing in MPEG-2 at high bitrates. I still frameserve via AviSynth for subsequent editing, post processing, and encoding.

[Edit: corrected intra-frame terminology]

[jggimi]

3. I searched this forum for a thread about Hardware Encoders VS Software Encoders - didn't find anything besides a very small thread that doesn't explain much.Most inexpensive capture equipment captures uncompressed video. Capturing into MPEG or other codecs uses your PC's CPU. The results are dependant on the power of your PC, and the PC operating system (and other applications and background tasks), to be able to keep up with the video as it comes in from the equipment. If you look at all of the discussion around dropped frames, you will understand the issue. Capture equipment that does hardware encoding presents already compressed video to your CPU, typically MPEG-2. There is much less concern about dropped frames, and, with some equipment, no concern at all. A number of people use digital video cameras as their hardware encoders, and those typically use DV codecs rather than MPEG-2, but the result is the same, the encoding is done outside of your CPU.

In addition, most inexpensive capture equipment does not capture audio, instead, the audio is captured by your sound card. This leads to the other popular problem besides dropped frames -- audio sync.

I hope this answered your questions.