Best Approach For Capturing Video Intended For Both DVD and Blu-Ray?

[blazin-j]

Hello and Happy New Year To All!

Forgive me for such a long post, but I have a number of questions which are all related.

I am using FRAPS to capture video/animation off my monitor and I want to author it now on standard DVD and later on Blu-Ray disc. I want the outputs to essentially look the same, with one being a high definition version and the other being a lower definition version. Since I intend to make a Blu-Ray version later, I am capturing the source video at 1920x1080 resolution, knowing that I will need to downsize to 720x480 to be compliant with the standard DVD spec. But I figure this is a better quality approach than capturing at 720x480 and then trying to up-size to a higher resolution.

FYI - FRAPS captures to a compressed .AVI file at a 4:3 video aspect ratio, 1:1 pixel aspect ratio, and in an upper/top first interlaced mode. As far as I am aware, these are fixed (i.e., I can't change the way the FRAPS codec works), so I am just relaying this info to let you know information about the source file.

Also, I do not have a Blu-Ray burner or player at this time, so I have to ask these questions since I do not have the ability to experiment thru trial and error. I am hoping that someone with Blu-Ray equipment and/or knowledge can demystify this for me.

My questions revolve around resolution, aspect ratios and interlaced vs progressive scan modes and how all these variables work together. To make this easier to follow, I'll try to break these down into bite size queries to make it easier to answer.

I. BLU-RAY SPECS:
I found the following information about video frame size elsewhere on this site:

High Definition Video:
1920x1080x59.94i, 50i (16:9)
1920x1080x24p, 23.976p (16:9)
1440x1080x59.94i, 50i (16:9) AVC / VC-1 only
1440x1080x24p, 23.976p (16:9) AVC / VC-1 only
1280x720x59.94p, 50p (16:9)
1280x720x24p, 23.976p (16:9)

Standard Definition Video:
720x480x59.94i (4:3/16:9)
720x576x50i (4:3/16:9)

Question #1: When I look at the High Definition Video section above, there are six (!) specs listed, so I am wondering if I am proceeding the right way in capturing the source file at a 1920x1080 resolution or if, for example, I should be capturing at 1440x1080. Ideas? I've ruled out 1280x720 because I want 1080 quality.

Question #2: What FPS rate should I instruct FRAPS to capture at? I know that animation appears to be smooth to the human eye at about 30 FPS, which is what I am shooting for (29.97 FPS), but can I get away with 23.976 FPS? If I am capturing at 29.97 FPS and then encoding at 23.976 FPS, doesn't that mean about 6 FPS get dropped? And wouldn't this open the door for the video to become a little jerky? It seems like I should encode/author at the same FPS rate that I capture so frames aren't dropped, right?

Question #3: What does "AVC / VC-1 only" mean for the two 1440x1080 specs listed? I'm asking because 1920x1080 and 1280x720 are both a 16:9 aspect ratio, which I am assuming is the same as "wide screen", but 1440x1080 is a 4:3 aspect ratio. That seems to suggest a "full screen" display, but the spec shows that at a 1440x1080 resolution it must be in a 16:9 aspect ratio to be Blu-Ray compliant. If I am capturing at a 1:1 pixel ratio, but what pixel ratio does a standard or HD TV display in? My confusion is centered on the difference between video aspect ratios and pixel aspect ratios... Since I don't want my video "squashed" (i.e., stretched horizontally to fill the screen), I am trying to capture in a wide screen (i.e., 1920x1080). It's tempting to try to capture at 1440x1080 instead since that's a lot less pixels, but would that mean that the video would get "squashed" when viewing it or be displayed "unsquashed" but with black borders on the left and right side of the video?

II. DOWNSIZING TO STANDARD DVD:

If my source file is at 1920x1080 or 1440x1080 resolution, I must downsize the files to 720x480 to conform with the DVD spec. Those resolutions are at a 16:9, 4:3, and 4:3 ratio, respectively.

Question #4. Since I want the standard DVD to look essentially the same (when viewed) as the Blu-Ray disc, just at a lower resolution, is it simply a matter of telling the encoder to encode at 720x480 using a 16:9 aspect ratio instead of a 4:3 aspect ratio? If so, wouldn't this essentially mean that the DVD would essentially be in widescreen or letterbox format (with black borders above and below the video)?

Question #5. How does "anamorphic" widescreen fit into all of this and how does one encode/author an anamorphic widescreen DVD? I guess I've not seen an anamorphic option in my software anywhere, so I'm not sure how it is done.

Thanks in advance for reading this long post and offering your expertise. If I were only producing a standard DVD it wouldn't be so complicated, but I am trying to do this with producing a Blu-Ray disc in mind later and I want the two to look essentially the same in terms of proportions.

[minidv2dvd]

post a sample of a fraps avi. it's most likely not interlaced because computer displays aren't, nor 4:3 unless you have your monitor set to a 4:3 resolution. sounds like it writes whatever your monitor/game size is to a type of slightly compressed mjpeg/avi. if your monitor is set to 1920x1080 and you record at 60fps, you should have a good source for HD or SD encodes. for SD it will need to be encoded down to 720x480 interlaced 29.97 mpeg-2 for standard dvd. the biggest question is whether or not your editor/encoder will accept the fraps avi as input.

[blazin-j]

OK, I ran a couple of tests after reading your post and you are right about the reported aspect ratio. My original capture at 1920x1080 created a 16:9 video aspect ratio because that is the aspect ratio of the captured video. When I captured the video at 720x480, the video aspect ratio is 3:2. What remained constant, however, was a 1:1 pixel aspect ratio, which I am assuming is the shape of a computer pixel (square).

As for whether or not an editor/encoder will accept FRAPS avi as input, I've not encountered any problems. But if I were to distribute the FRAPS avi file to someone who did not have the FRAPS codec installed, then they could not play the file.

In any case, the broader questions I asked earlier still stand unanswered. Any input would be appreciated.

[edDV]

Q4: Your need for quality at the SD DVD level drives most of the strategy. DVD can be 720x480i/29.97 (wide or 4x3) or 720x480p/23.976 (wide or 4x3). 23.976 fps is too low for fast game play. 29.97 fps progressive can be "faked" by choosing both fields from the same frame. 480i gives 59.94 fields per second hence the best motion smoothness. Your choices here point to best HD capture strategy.

Assuming a 480i/29.97 SD DVD, then,

Q1: Few games produce 1920x1080 resolution except by player upscale. You or your HDTV will do a better upscale so why not cap 1280x720? If the game can output 1440x1080i, then that saves you 25% bitrate or allows 25% better compression quality vs 1920x1080i. If 1920x1080i out is the only choice then you are going to have to accept lower compression quality. I still vote for 1280x720p/59.94 capture unless you are sure the game you are playing is native 1920x1080 and you can accept 29.97fps motion vs 59.94 fps.

Q2: 29.97i is actually 59.94 fields per second. 29.97p is jerky. try it. 1280x720p capture allows either 59.94p fps or 29.97p fps. Your choice.

Q3: That means a Blu-Ray player will only accept those resolutions for the h.264/VC-1 codecs, not MPeg2.

1920x1080 and 1280x720 are square pixel. 1440x1080 and 720x480 have non-square pixels. All can be 16x9 wide. HD is wide by definition.

[blazin-j]

Thanks @EdDV for your advice. Allow me to provide a little more info to factor in the equation.

1. I am capturing from a window, not a screen, so I can resize the window to any dimensions. I'm just trying to figure out what the ideal window size should be before I go about the business of capturing. The problem is that the larger the window size, the slower the fps rate I can get out of my PC. Increasing the capture fps rate will require me to invest in some newer, faster hardware. That's not out of the question, however. I'll invest in the hardware, if necessary, to achieve the desired output quality I am seeking. I'm just letting you know about this constraint because the video I am trying to capture is fast moving so I think I'll have to capture at 29.97 fps instead of 23.976 fps. Otherwise, it'll be jerky.

I am operating on the assumption that I can achieve better quality by starting at a high resolution (1920x1080 - for Blu-Ray) and then downsize to a lower resolution (720x480 - for SD DVD) rather than the reverse; that is, capturing at 720x480 and then upsizing to 1920x1080. That 'always downsize' principle seems to work with photos/images, so I'm assuming that's true with video too.

If I follow you, your suggestion is to capture at some middle resolution (e.g., 1280x720 or 1440x1080) to achieve a better compression quality on the SD DVD and then upsize to 1920x1080 (or don't upsize but rather allow the HDTV to upsize on the fly) for the Blu-Ray version. Is that correct? It's a good, balanced approach, I suppose, and will help alleviate the capture fps constraint too since it'll be less pixels to capture than 1920x1080, but I wonder how the play quality would compare against something that was captured at 1920x1080 (and hence require no resizing). I would assume it would not be as "high def" as the 1920x1080 capture, but any idea of how big the 'hit' to perceived quality would be? I guess I'm trying to weigh the pros and cons to figure out what the best overall solution is. I don't want the Blu Ray to look great and the SD DVD to look crappy, or vice versa. I want them both to look as good as possible.

2. I should also tell you that the video will be about 1 hour long. Thus far, I have been able to encode (via MainConcept and Procoder) video captured at 720x480 resolution at a very high bitrate (9 MBR) and still fit it on a 4.7 Gb DVDR even with the sound/music included. I have not yet tried to capture at a higher resolution (e.g., 1920x1080), however, and then downsize to 720x480 to see what type of compression quality I can achieve on the SD DVD because I'm not sure what the best window size I should use. It's kind of a circular dilemma, lol. But even if it did not fit on a DVD5 using a high bit rate, I could always burn to a DVD9 to achieve the highest bitrate possible.

As for Blu-Ray, I'm assuming that the bitrate isn't going to be a big constraint either because it's my understanding a much higher bitrate is allowed by the Blu-Ray spec and the storage capacity of a BDR is huge.

3. Just to reiterate about FRAPS capture -- it only captures interlaced, not progressive. As Minidv2dvd mentioned, I guess monitors only scan interlaced. So, to convert from interlaced to progressive, I've have to do that when I encode and I'm not sure if that change will cause a quality degradation.

So, in summary, my simple thinking thus far is that the "best" approach would be:
A. Capture at 1920x1080i at 29.97 fps.
B. Encode SD DVD at highest possible bit rate and author at 720x480i and 29.97 fps. This way, there is no change to frame rate, only resolution.
C. When I get the Blu-ray burner and player, encode at highest possible bit rate and author at 1920x1080i, 59.94 fps. This will only mean changing the frame rate, not the resolution.

What do you think about this approach?