Beginner Questions

[geeves]

Hi there, was hoping someone could answer a couple questions for a beginner user with the software (version X6).

1. When creating a custom mpeg2 file, in compression settings, what is the speed/quality toggle actually changing? It doesn't seem to make a noticeable difference.

2. Should I leave the video data rate variable or constant? What's a good rule of thumb for the number it should be?

3. When creating a custom mp4 clip, whats the difference between H.264 baseline, main, high (and when should I use which?) Again, what data rate should I use for each?

4. Should I. Leave my video in its native resolution 640x480 or up convert to 1280x720 for HDTV viewing?

5. In addition to editing videos, I would also like to take other raw .avi files that are (50+ GB). In order to compress my videos I'm uploading them into Corel and then just exporting them with no modifications. Is there a better way?

6. What's the significance of using 720x480 vs 640x480? If I took my 640x480 video and outputted it to 720x480, would it stretch it? It seems the only resolution for DVD is 720x480, how does it maintain the 4:3 or the 16:9 resolution?

7. Should I leave non-square rendering checked or unchecked?

8. Should I leave my frame type as lower field first or upper field first? I've read somewhere else on this board that it should match the original clip's setting. The original clip I have is an avi captured from 8mm tape playing through a camcorder. How can I check what my original clip's setting was? Do I have to look on the camcorder itself?

Thanks in advance for any help given!

[Ken Berry]

1. When creating a custom mpeg2 file, in compression settings, what is the speed/quality toggle actually changing? It doesn't seem to make a noticeable difference.

The default setting is supposed to represent a good balance between the speed/time taken to render the video and its final quality. If you move the slider up, the render will take (much) longer, and the quality is supposed to be better, if only marginally. Some people swear by it but I simply leave it at its default setting.

2. Should I leave the video data rate variable or constant? What's a good rule of thumb for the number it should be?

Some people choose one or the other. If your project is relatively short and will fit on a single layer DVD with a high bitrate (8000 kbps), for example, then you can use constant. But if the project is a bit longer and involves a mixture of action and calmer footage, the VBR is probably better as it uses a higher bitrate for the action parts but doesn't need high bitrates for the quieter bits. If producing a DVD on a single layer disc, you can fit about 70 minutes onto the disc using Dolby audio. A 90 minute project would require the bitrate to be lowered to around 6000 kbps, and a 2 hour video to 4000 kbps. Lowering the bitrate lowers the quality and the latter would be no better than VHS tape.

3. When creating a custom mp4 clip, whats the difference between H.264 baseline, main, high (and when should I use which?) Again, what data rate should I use for each?

I'll leave this for someone else since I don't tend to use them for formatting purposes.

4. Should I. Leave my video in its native resolution 640x480 or up convert to 1280x720 for HDTV viewing?

It depends what you are going to do with it. If, as you suggest, you are going to look at it on a big HDTV screen, the 640 x 480 is not going to look too flash. The problem with up-converting it is that the program is having to invent pixels out of nothing -- or rather by duplicating existing pixels. That won't be a good look either. See also (6) below.

5. In addition to editing videos, I would also like to take other raw .avi files that are (50+ GB). In order to compress my videos I'm uploading them into Corel and then just exporting them with no modifications. Is there a better way?

I'm not really sure what you mean here. Do you mean you are "just exporting them" with exactly the same properties as the original? If so, what is the purpose of that? Or do you mean you are converting them to another format but not doing any editing to them? If the latter, there is no real reason for that either. Raw or uncompressed .avi is huge, yes, but nonetheless a valid video format which can be edited before outputting into another format. To an extent, though, this will depend on how powerful your computer is since 50+ GB of video data is significant and could need a lot of computing power, especially if the end format is another complicated one such as AVCHD.

6. What's the significance of using 720x480 vs 640x480? If I took my 640x480 video and outputted it to 720x480, would it stretch it? It seems the only resolution for DVD is 720x480, how does it maintain the 4:3 or the 16:9 resolution?

Again it depends what you are wanting to produce. If it is a standard def DVD, then you cannot use 640 x 480 as it is not one of the DVD-compatible formats under the international DVD standard. 720 x 480 is perhaps the most common NTSC DVD format. If you burn your original footage to DVD, it will have broad black stripes down each side. Though 720 x 480 does not appear to be 4:3 or 16:9, those resolutions are achieved by the video using non-square i.e. rectangular pixels.

7. Should I leave non-square rendering checked or unchecked?

Again, I have to pass this one on to someone else to answer as I simply have never used 640 x 480 footage. But it would be easy enough to check yourself. Take a short piece of your original footage and render it using the 720 x 480 setting with non-square pixels checked. If the end result is not satisfactory, try it with that selection unchecked.

8. Should I leave my frame type as lower field first or upper field first? I've read somewhere else on this board that it should match the original clip's setting. The original clip I have is an avi captured from 8mm tape playing through a camcorder. How can I check what my original clip's setting was? Do I have to look on the camcorder itself?

A fundamental rule of video editing is to always maintain the same Field Order throughout a project. So if your original video uses Lower Field First, you must use this through to the final render. As far as possible this also means you should avoid mixing Upper and Lower Field First video in the same project. The problem these days is that most video is now Upper Field First, with mainly only DV/AVI video using Lower Field First. VS uses Upper Field First by default, so you have to change that if your video is LFF. You can right click on one of your original clips in the VS timeline and select Properties to see what Field Order it uses.

[geeves]

Thanks so much! Your answers helped a lot.

[geeves]

I should clarify my question 5. I just read it and it didn't make sense.

What I meant to ask was is there a better way to cut down on the file size of a 50+ gb avi file? (Like a converter or compressor of some sort) I'm not interested in editing the video.

Currently, I'm just placing the clip in Corel and exporting it into a different file format (MPEG or mp4)

[Ken Berry]

No that's fine too. What format you convert it to in VS, though, will still largely depend on what you intend to do with it eventually. If you intend to make a DVD, as I said above, at some stage or other, it is going to have to be converted to mpeg-2, so why not use that as your first conversion format. If you intend to make it high def, then convert it to either transport stream mpeg-2 (*.m2t) or AVCHD, both of which are Blu-Ray compatible and should play directly on your HDTV from an external USB hard disk or stick drive either plugged directly into the TV or else into an attached Blu-Ray player...

[Ken Berry]

I've done a little research on your question 3 since no one else has jumped in on it. Here is what Wikipedia has to say about the three classifications. It will possibly seem to contain a lot of gobbledegook. But essentially, it boils down to baseline being for essentially low quality stuff; main for standard def and high, obviously enough for high definition work.

Baseline Profile (BP)
Primarily for low-cost applications that require additional data loss robustness, this profile is used in some videoconferencing and mobile applications. This profile includes all features that are supported in the Constrained Baseline Profile, plus three additional features that can be used for loss robustness (or for other purposes such as low-delay multi-point video stream compositing). The importance of this profile has faded somewhat since the definition of the Constrained Baseline Profile in 2009. All Constrained Baseline Profile bitstreams are also considered to be Baseline Profile bitstreams, as these two profiles share the same profile identifier code value.
...
Main Profile (MP)
This profile is used for standard-definition digital TV broadcasts that use the MPEG-4 format as defined in the DVB standard.[36] It is not, however, used for high-definition television broadcasts, as the importance of this profile faded when the High Profile was developed in 2004 for that application.
High Profile (HiP)
The primary profile for broadcast and disc storage applications, particularly for high-definition television applications (for example, this is the profile adopted by the Blu-ray Disc storage format and the DVB HDTV broadcast service).

As for what bitrate you should use with each, if you look at the defaults in the VS templates, that should give a guide. You'll probably also find that baseline and main are more limited in frame sizes than high, and that you can, if you want, use a higher bitrate with the latter. VS will tell you if you choose a bitrate which is too high for the format.

[geeves]

Again Ken Berry, thanks so much for your answers. This really helps a lot esp. when starting from level 1

[geeves]

On a follow up note to using 720x480, I noticed my capture device has the option for 720x480 or 640x480. I'm capturing video from a canon 8mm tape camcorder. I automatically assumed 640x480 should be the resolution to capture at. But now I'm not sure.

[geeves]

The videos will be made into DVD and MP4 which I found I can do when the resolution is 640x480. I want to know if there is an advantage to capturing at 720x480 (better quality) or is there virtually no difference?

[canuck]

If you are going to create DVDs (Which are 720x480) then obviously capture to that format. You would have to convert at some point anyway.