Best Quality SVCD

[KWG22]

I've been reading here and experimenting for about a year now. I think I am understanding most of the concepts, but have this "bottom line" question-If I want to make the best quality SVCD possible, with no concern as to how many CD's will be used, Constant Bit Rate set at the max for the SVCD format(to 2600) would be the way to go-is this correct?
I know one of the improvements of SVCD over VCD is Variable Bit Rate, but if you just want to have the best quality, and are not worried about how many CD's are used, then it seems you don't need to use it. But is CBR set at Max, overkill? Guidance would be greatly appreciated!
Thanks.

Kevin

[Kdiddy]

well an xVCD can use VBR as well, so the VBR is not really the true gain of SVCD over VCD. But if you are not concern with number of disks, then yes, CBR is the way to go, your clips will encode much faster than VBR. test some small sample clips, some players can support bitrates higher than 2.6 mbps...if you really need that quality, you might be able to go higher.

[kinneera]

You may as well use one-pass VBR and let the encoder save you bits where they aren't really needed to maintain the quality level.

[Nelson37]

WOW do I disagree with Kdiddy on this one.
1. VBR is an advantage of SVCD over VCD. xVCD is by definition NOT VCD and therefore is irrelevant to the first statement.

2. CBR may be faster than 1-pass VBR (or it may not, I haven't tested this), but this is again irrelevant. The question was regarding QUALITY.
By using multipass VBR with a max set higher than 2600, high-motion scenes can utilize the extra bitrate to eliminate pixelation. SVCD requires an AVERAGE bitrate of 2620, it does NOT require that at no time will the bitrate exceed that limit. In fact, its support of VBR inherently suggests that some sections will exceed 2620 while other sections fall below that amount. To dictate CBR robs high-motion scenes of needed, and available, extra bitrate and therefore quality.

Now if you want the best-looking VoCD (that's Video on CD, a generic term) you can make, try 720x480 with a bitrate as high as your player can support, 3000-4000 works for me, 30-35 minutes on 800MB cd. The drawback is your player may not handle it.

[siaododo]

I agree that you can set your video bit rate to as high as you can, but what is the point if you have to get up every 30 minutes to change the CD & to use 3 to 4 CD's to store 1 movie. ( I am assuming that most everybody is ripping DVD movies to CD's, if you have a short clip, well, you can set the video bit rate to as high as you can to get it to fit on 1 CD).

Personally I prefer to use 2-pass vbr, (to tell the truth, I cannot tell the difference btwn 1 pass & 2 pass, but what the hell, 2 is better than 1), I can use bit rate calculator to get the average bit rate, so I can control the file size to fit the CD & still maintain the quality that I can live with. I would usually set the min bit rate to 0, because I figure any scene will always be higher than 0 bit rate.

I have seen other posts that mentioned putting 2 hours of movie on 1 CD, I have tried it, andI just didn't like the quality it produces, but that is just my personal opinion.

Any way, I set my personal limit to 2 CD's per movie, & use 2-pass VBR when I am making SVCD's.

[Kdiddy]

Kinneera: Im a lil lost on why you said what you did. A CBR clip done at 2.6 mbps would have the same if quality as a VBR clip where the max was set to 2.6 mbps, would it not? I realize we are truly dealing in only theory because I seen enocders go above & below specified values.

Nelson37: Well to clairfy, to me I draw the line tween SVCD & VCD, with mpeg1 & mpeg2....VBR or CBR makes no difference, I know that is not standard hardline strict doctrine way of thinking of it....but all this XVCD,seVCD, yadda yadda is not really worth when major difference tween to 2 is what mpeg compression is being used. Although is the running debate about true diferrences tween the compression schemes, but thats another story.
As I just asked Kinnneera, it is my understanding that CBR done at same level as max bitrate set on VBR would give you the same quality. There would be no "extra bitrate". So again, if he's choosing between a CBR mpeg2 at 2.6 mbps vs. a VBR mpeg2 with values of 300-2000-2600, and has no concern for size of the mpeg2 file, then I would go with CBR. I choose the values of 2.6 mbps as an example, as not only the SVCD standard avg bitrate, but a lot of players have problems handling bitrates higher than this from the VCD/SVCD format. My player doesnt, but I seen other players that have.

[Nelson37]

Kdiddy - you're changing the question. with CBR set at 2600, Avg bitrate will be 2600. With VBR min-500 avg 2000 max 2600, Avg bitrate will be 2000, or very close. This will give a smaller, worse looking file. The proper comparison would be VBR min-500 avg-2500 max-3000. Values are approximate as I find CCE is somewhat inaccurate on the chosen avg value. The whole point of VARIABLE bitrate is to set the avg at your target rate, with higher and lower max and min, thereby creating a range of bitrate assignment accounting for differing scene requirements.

Taking the first settings stated above, VBR avg-2000 max2600 and CBR 2600, CBR will be both bigger and better. BUT - VBR avg 2500 max3000 will be same size as CBR 2600 (or very close), significantly better quality due to the max 3000, AND SVCD compliant, whereas CBR 3000 would be non-compliant and much larger.

[deltaboy]

so then what would be the max bitrate allowed in a Compliant VBR SVCD?

2520? 2600? 3000? 3000+?

[bewley]

Some things to keep in mind and some tricks for improving quality...

Many standalone DVD players have 2X speed drives with a maximum throughput of around 2748 kbps. One way to increase the visual appearence of a clip is to raise the video bandwidth and lower the audio.

Here are some examples:

vid: 2517 kbps aud: 224 kbps
vid: 2582 kbps aud: 160 kbps
vid: 2614 kbps aud: 128 kbps
vid: 2630 kbps aud: 112 kbps

Another tip is to keep in mind that part of the picture "lives" inside of your TV set. Never encode an SVCD at 480 x 480 (NTSC), instead set the encoded picture to 448 x 448 and add borders to fill in the rest of the space and bring the clip back up to 480 x 480.

If you find that you have a clip that requires lots of bit rate, you could also try making an 1/2 DVD resolution SVCD. This is an SVCD with a resolution of 352 x 480 (320 x 448 encoded picture). Yes, it doesn't look as sharp as a standard DVD, but there is much less of a chance of brick noise.

As was suggested earlier, if your DVD player can hang, set the clip to 720 x 480 and encode around the 3K - 4K level. Just remember, if you get another DVD player in the future, these discs may no longer play.

If you are converting an NTSC film DVD, make sure to convert it to Film (23.976 fps) and then run PULLDOWN (or set TMPGEnc to 2:3 Pulldown). This will save you 20% overhead and give you better looking encodes.

Lastly, I believe there is a lot of myth associated with the whole VBR vs CBR debate. An encoder will only assign as much bit rate as is needed to a clip... Period. If you have a sequence that only requires 2000 kbit, and you are set at 2600 kbit CBR, the encoder makes up the difference by padding the extra 600 kbit with empty space. There is no quality gain in this situation. Unless you max out your settings, VBR is preferable as CBR will waste bit rate on clips requiring less bandwidth and will suffer a shortage on those requiring more.

To test this, take a 5 minute clip and encode it twice. First, use 2600 CBR and then use VBR set at MIN: 0 MAX: 2600 AVG: 2600 (no padding). What happens is that both clips will look exactly the same, but the VBR clip should take up less space -- assuming, of course, that the clip doesn't peak over the 2600 bit rate point the entire time.

So, KWG22, yes setting your encodes to MAX CBR is probably overkill for most standard SVCD's. However, if you have a slower PC and the number of CD's is no worry, I wouldn't see any reason to change your current procedures -- unless your standalone will accept a resolution and bit rate higher than the standard.

Good luck!

[bewley]

Nelson37,

Kdiddy - you're changing the question. with CBR set at 2600, Avg bitrate will be 2600.

Although that is true, there is more. With CBR set at 2600, the AVG, MIN, and MAX are set to 2600 -- with padding when the encoded bit rate falls below 2600.

Taking the first settings stated above, VBR avg-2000 max2600 and CBR 2600, CBR will be both bigger and better. BUT - VBR avg 2500 max3000 will be same size as CBR 2600 (or very close), significantly better quality due to the max 3000, AND SVCD compliant, whereas CBR 3000 would be non-compliant and much larger.

Agreed. The only problem is that setting a VBR encode to a max of 3000 will make it invalid for many standalone players. A better way would be to make MIN, MAX, and AVG all 2600. This will produce a file that looks exactly the same as the 2600 CBR file, will be compatible with all equipment able to play SVCD, but is smaller than the 2600 CBR file -- unless the clip stays maxed over the 2600 level.

[bewley]

To prove I am not completely batty , I just put together a little test and received the expected results.

First, I created the following Avisynth script:

Blackness ( 900, 480, 480 )

This creates a ~30 second long 480 x 480 completely black clip.

Next, I loaded this into CCE and encoded using 2600 CBR. The result was a video file 11,902 KB in size.

Next, I loaded this into CCE and encoded using VBR with MIN/MAX/AVG all set to 2600. The result was a video file 519 KB in size.

Although this is no way a "real world" test, it just shows how much wasted space *CAN* appear in a CBR encoded video file. Both videos play back and look the same to me -- black. :P

OK, that's enough fun for one night. The movie "O" is giving me hell, but the IVTC.DLL plugin seems to be doing the trick! Back to work...

G'night,

[Kdiddy]

Nelson: I think you straying way off topic from the what the original poster asked and wanted, I stayed within the frmaework of his question which was,

Constant Bit Rate set at the max for the SVCD format(to 2600) would be the way to go-is this correct?

But is CBR set at Max, overkill?

to which you stated:

With VBR min-500 avg 2000 max 2600, Avg bitrate will be 2000, or very close. This will give a smaller, worse looking file.

In theory a mpeg with the max VBR set to the same as the CBR, the quality will be the same. The because the encoder will allocate the high bits to the scenes that require it, and low bits to scenes that dont. Thus, in theory, you would not be able to tell the difference. The fact that you say you can, is a fallacy of he encoder, not of the mpeg compression algorythm. To which I agree with what bewley has stated.[/quote][/b]

[Nelson37]

The operative part of the original question was "want to have the best quality SVCD". If max bitrate is 2600, or CBR is 2600, then you never go over 2600 whether you need it or not. Assuming that a scene would use a bitrate of 3000, or any higher number, and that this scene would be of better quality using 3000 rather than 2600, using an avg of 2600 and a max of some higher number will give a better quality mpg than a CBR of 2600.
Yes the question was framed referencing CBR @2600. IMHO, the value of Variable bitrate was not being fully utilized.
As far as seeing the MAX VBR = CBR difference, consider a high-action movie wherein the avg of 2000 cannot be achieved without allocating some hi-action scenes less than the 2600 maximum bitrate; resulting in pixelation. CBR 2600 would alleviate this to some extent at the cost of filesize, however, consider VBR avg 2500 with MAX of 3000, this would allow even more bits for hi-action while still maintaining same size without breaking SVCD specs. The max is only dependent on what your player will handle, within reason considering the averaging.
Try this with an NFL game, for example, and I believe you will see the difference as I did. Watch the line of scrimmage at the snap, that's where your max bitrate is used for a very small percentage of time.

[kinneera]

Kinneera: Im a lil lost on why you said what you did. A CBR clip done at 2.6 mbps would have the same if quality as a VBR clip where the max was set to 2.6 mbps, would it not? I realize we are truly dealing in only theory because I seen enocders go above & below specified values.

It sounds like you understood my point... A single-pass VBR encode essentially throws out data where it isn't necessary to maintain a constant quality level, which is to say it is more efficient in the sense that you should be able to fit more video into a given space at the same quality level. This is only relevant if you are dealing with a length of video where an average bitrate in a 2-pass encode actually exceeds the allowable maximum bitrate of the target decoder (e.g. in this case a typical DVD player that chokes on any combined bitrate above ~2700Kbps). Basically, if you are making a standards-compliant SVCD with only 30 min. of video, 2 or more passes is pointless and CBR is less efficient.

As you're probably noticing though, its hard to conceive of many such circumstances, as most of us will attempt to cram much more data onto a disk if we see a reasonable amount of excess space (say, two 30 min. episodes instead of 1), thus necessitating the best quality-to-space capability of a multi-pass encoder. Still, from a theoretical standpoint, its an interesting discussion. Essentially what I'm getting at here is that there is no value to CBR unless it is mandated by a standard or specification. I think the clip-of-blackness test bears witness to this.

[Kdiddy]

The max is only dependent on what your player will handle,

Which is why I said the max of 2.6 mbps, because most players will not handle above this rate, thus any value above this is a moot point...its apple to oranges really and not worth beating this dead horse over. In the framework of which he pose the question, CBR at 2.6 mbps will be better for HIM in terms of speed & quality, than any VBR with the max variable set to same bitrate as the CBR, and the average being lower.

[kinneera]

In the context of the very original post, since the length of video to be encoded isn't specified, my advice would still be 2-pass unless time is an extremely high priority. If time is an issue, then I would say 1-pass VBR set to an applicable maximum, to ensure the greatest amount of video per disc at a consistent quality, since 1-pass isn't really significantly slower than CBR. I would never recommend CBR.

[SatStorm]

In theory, CBR is the best.
But in real world, there are more.

First of all, if you want good results for your encodings, you need:
1. Insert Intra frames when a scene changes
2. Rescale the picture

Rescale the picture is neccessary for VCD/CVD/SVCD creation. For DVD may be not neccessary.
Technically speaking, it means also a few things more: The allocation of data per frame ('cause there is no encoder rescale fields, that's what Tsunami study in the new release of his encoder) and the colour allocation. Rescaling is not an easy task.
With Interlace source, it is also a need of choosing the best of the two fields. De-interlacing or Filter the source, produces good results but it is not (technically speaking) a solution. It is a trick...
So a good CBR file, must be at least a 2-pass CBR file.

Now: When you go 2 pass, you know more for your source than the above: Where and when your output file needs more or less bitrate, where the colours are, and when you have to use the one method of rescale or the other (bilinear, Bicubic, etc).
It is stupid NOT to use those infos. So, you go VBR just because you can use those extra infos.

The 1 Pass VBR fuction of some encoders, do something like "buffering" a few next frames and encode. It is slighty better CBR, but not as good as multiPass VBR

So, for someone who wants quality, I suggest 2 Pass VBR with minimun 800, and Average/Maximum at the Value of a CBR file. It takes double time to encode, but you get the best you can!

This is my opinion. Other users may have different one

[Nelson37]

Sorry to argue this folks but my wife pissed me off anyway...
Some players won't handle over 2600, well some DVD players won't play SVCD - no reason to abandon the format. I read in the list a large number of players will play miniDVD, XSVCD. My $99 Apex handles well over 3500. IF your player will handle the bitrate, particularly for brief spikes, dozens of test encodes (NFL games, Digital Cable, DVD rips, broadcast) show me that a higher max bitrate does result in better looking video, specifically reducing or eliminating pixelation in hi-action scenes.
To each his own.

[Mdanner423]

All this techno crap means nothing if the video looks bad on your tv. I suggest makeing several test clips using diffrent settings and seeing which one YOU like more. I have been doing this for a while, and i have a 61 inch tv, when useing variable it looks bad, because it doesnt seem to calculate the bitrate you will need by the size of the screen you are useing... So on my normal tv, variable and cbr look the same but when you project it big you can tell a HUGE diffrence. I am recording at Mpeg-2 6000 CBR, and the quality is PERFECT in everyway. DVD-R, if you have any ?'s e-mail me!

Matthew

[Kdiddy]

My $99 Apex handles well over 3500. IF your player will handle the bitrate, particularly for brief spikes, dozens of test encodes (NFL games, Digital Cable, DVD rips, broadcast) show me that a higher max bitrate does result in better looking video, specifically reducing or eliminating pixelation in hi-action scenes.
To each his own.

So on my normal tv, variable and cbr look the same but when you project it big you can tell a HUGE diffrence. I am recording at Mpeg-2 6000 CBR, and the quality is PERFECT in everyway. DVD-R, if you have any ?'s e-mail me!

Again, all this extra info is nice, but can we stick to what the original poster requested. We are talking about HIM, what HE desires, & HIS player (since he didnt specify with have to go with the assumption that its like most players which will not play above 2.6 mbps). Im not arguing that VBR with a max bitrate above a CBR bitrate is better quality, thats a no brainer. As is any video CBR/VBR at 6 mbps will look better than than a video done at 2.6 mbps. But that's not what he asked. Therefore, whatever the max bitrate for his player is, he can either set CBR to that or VBR min=0, avg & max = max player for player. In order to get that best possible video without regards to saving space.

[KWG22]

Well, I struck a nerve! Thanks for all the replies. I'm going to go over them again when I have more time. Kdiddy, you do indeed get back to the question I asked. However, I am interested if my or most players of those to which I give CD's, will handle spikes of higher bitrates. I just was going by what I had read re: max bitrate of the SVCD format.
Some specifics as to what I'm doing: I'm not ripping movies from DVD. What I will be encoding are either shorter projects or things such as a home movie project(taking video transferred from old 8mm films and more recently, VHS tapes) where it will be acceptable to have multiple discs if quality can be maximized. Again, thanks for the input and all further is welcomed!
Kevin

[kinneera]

However, I am interested if my or most players of those to which I give CD's, will handle spikes of higher bitrates. I just was going by what I had read re: max bitrate of the SVCD format.

If your player isn't in the compatibility list, the only way to find out is to test the highest bitrate your player will handle. I recommend CD-RWs for this.