bitrate settings

[rodrigoveron]

I use dvd2svcd to rip my dvds and create svcds, currently i have my bitrate settings like this
Avg. 1600
Max. 1720
Min. 500
I have seen that some people use settings like this:
Avg. 1600
Max. 2520
Min. 1150
What is better? and what is the quality setting in cce for?

THANX

[thefox149]

It's size vs quality......

I have gotten really good quality for a CVD using dvd2svcd....1hr30 min film onto 1 disc (in the old days I would have definatly used two discs) but have seen I can get comparibale quality the bitrate was about 1900 approx(I am sure if you have a high definition tv would notice big time) but on my 68 cm tv you have to look ver very closely to be able to tell the difference between the copy and the original. I use 3 pass in CCE with the image slider set to 17 (standard dvd2svcd option) with the antinoise off. I am very happy with the results.

[poopyhead]

It's size vs quality......

not in this case.

I use dvd2svcd to rip my dvds and create svcds, currently i have my bitrate settings like this
Avg. 1600
Max. 1720
Min. 500
I have seen that some people use settings like this:
Avg. 1600
Max. 2520
Min. 1150

notice the avg. bitrate is exactly the same in both cases. assuming he's using multi-pass VBR, which i assume he is because of the avg, min, max settings, then filesize is ultimately determined by the avg. bitrate. since avg. birate determines, on avg., the filesize (i.e. 1.6 mbit) per amount of movie time (i.e. per second), then no matter what the min or max bitrate setting is, it's the avg. birate throughout the entire movie that will determine the filesize. so, for any scene that has higher than the avg. bitrate, then there will be a corresponding scene that has a proportionally lower than avg. bitrate, so on avg. the bitrate will correspond to the avg. bitrate.

@rodrigoveron,

you need to set the avg. bitrate based on the amount of movie you wanna fit per disc. obviously, higher bitrate means you can fit less / disc.

however, you should give a wider range for min and max bitrate. try max=2520 and min=200. this will allow cce more flexibility in determining which scene needs more bitrate and which ones need less. hence, the closing credits (just scrolling text), might only need 200 kbit/s as the bitrate (it's just text), so that a high action scene can steal the unused bitrate from the end credits. in the end, this will allow CCE to better allocate the bitrate, transferring bitrate from low action scenes to high action scenes that need more bitrate.

[thefox149]

i stand corrected

[ZippyP.]

... you should give a wider range for min and max bitrate. try max=2520 and min=200.

I use similar settings for my encoding. I agree, the encoder needs a wide enough setting between min and max to properly allocate bitrate. Some people like to use a higher max setting but that will exceed SVCD specs, and I know my DVD player doesn't like it too high

[poopyhead]

I use similar settings for my encoding. I agree, the encoder needs a wide enough setting between min and max to properly allocate bitrate. Some people like to use a higher max setting but that will exceed SVCD specs, and I know my DVD player doesn't like it too high

actually, some DVD players don't like the bitrate too low either

[ZippyP.]

actually, some DVD players don't like the bitrate too low either

Yeah, mine. I set the min at 300 with padding enabled.

[SatStorm]

This is a good question. The short answer is: It depends!

If you use TMPGenc for your encoding, the the spread over the average bitrate goes like this: You have a typical movie with an extreme scene. So, you set 500 min, 1600 average, 2520 maximum. Well, TMPGenc gonna keep the movie close to ...500kb/s just to give it all the 2520 maximum to the extreme scene. So you end up with a bad encoding...

If you use CCE, the value you set over the average bitrate is more of cosmetic thing... Set 500 min 1600 average and 2520 maximum and CCE very rare gonna get lower 1000kb/s (use a bitrate viewer if you don't believe me...).

How this 1000kb/s is determined by CCE automaticly? Well, because there is a well know minimum bitrate needed to support a still image. Yes, you can go lower, but that harms the quality and the spread of the bitrate around the average value... In practice, for 352 X 576/480 a minimum bitrate of 1000kb/s is needed. For 480 X 576/480 this is about 1300kb/s. For 720 X 576, it is about 1800kb/s. For 352 X 288/240 in theory it is ~400kb/s but in practice there is not an official format to use so low bitrate. VCD, the lowest optical commercial media, is CBR at 1150kb/s...


And that rise another issue also. Even if it is possible to force your DVD or CD Rom to go lower that value (1150kb/s) that doesn't mean that you do good to it. The opposite: You push it a lot. So, those kind of lower bitrates can kill it really quick (8 - 12 months...)

Anyway, I and other advance users of this matters, advice to set the minimum value of CVDs and SVCDs, to 1150kb/s. Not because it is not possible to go lower. It is possible. But with this minimum value, you are not pushing your standalone's driver much and expecially if you use TMPGenc for encoding, you produce better results. You produce better results because you allow that way better data spreading over the average bitrate and because a minimum still image needs also a good amount of bitrate to be keeped as it should be.
That's also the reason DVB transmissions never go lower 1550kb/s....

[poopyhead]

@SatStorm,

not necessarily. i and other advanced users generally see that end credits need probably the least amount of bitrate. i'm pretty anal about the movies and want to keep as much in them as possible. that means no cutting out the end credits. so, if this is the case, setting the min bitrate lower than 1150 kbit/s would be better so that the end credits (non-images) would get as low of a bitrate as possible, while giving higher bitrate to other scenes.

[adam]

Unlike most other encoders, CCE lets you totally tweak how it distributes its bitrate using the image quality priority setting. You can make it apply a ridiculously low amount bits to flat scenes, or you can make it overcompensate and keep everything relatively equal. At my typical settings, my min bitrate drops down to about 500kbits quite frequently, but never drops much lower than this. I get similar results in TMPGenc as well. From my personal tests with various encoders, I get better results with low min settings, I just use 0.

Its true some dvd players will freeze up on low bitrates, but this is pretty rare.

[poopyhead]

I get better results with low min settings, I just use 0.

Its true some dvd players will freeze up on low bitrates, but this is pretty rare.

if min is set to 0, doesn't the encoder automatically make it 200? heard it from way back...

also, my pioneer dv333 seems to freeze up with really low bitrate (completely black screen during scene transitions....only happened on 2 movies so far..but still happened)

[adam]

0 as a min setting basically just means automatic. The encoder will simply allocate bitrate as normal but will not have a minimum amount of bitrate which it must allocate to any given scene. So if the least bitrate intensive scene in your movie only requires 500kbits, according to the encoder's calculations, than 500 becomes your min bitrate. If the encoder determines that 5mbits is the lowest it can go, relative to your other settings, than that becomes your min.

With a minimum of 0 I get actual min of around 500kbits.

[SatStorm]

Set to the latest TMPGenc minimum 0 average 2300 and maximum 2520 for the bitrate and if the result not suffer from quality decration, I quit my job! And currently is very difficult to find another soon!
CCE has a spread the bitrate system, TMPGenc don't.

@ Adam: I used to believe that, but I made a xVCD with an average of 800kb/s just for testing and many capable to play xVCDs standalones I tested it, couldn't play it correct or at all. Cyberhome, Amoisonic, Encore, Comet, Blue Sky, Yokohama, Crypto are some of those players. Yes, there are cheap, but extremely popular here. They have a 70% market share in Europe. But the real problem, is not the picture freezing. It is that the drivers those standalones use are of a so low quality... They broke down easy. The guarantee is 6 to 12 months at best and they tend to broke down the 13th month... You help a lot those low quality drivers if you don't go lower 1150kb/s. Sad but true..

@ poopyhead: Which encoder you use and what encoding method? And what source?
I'm asking you because this is impossible to be succeeded with TMPGenc and a typical PAL DVB or DV or avi analogue capture (mjpeg/huffyuv) as a source. If you know a good technick to encode from those sources (I don't talk DVD here and I talk only for PAL...) with the use of TMPGenc, I'll be glad to hear it. I'm a big failure in this matter. 3 years now, I don't have good results if I use a lower bitrate than 1000kb/s for CVD. Example: If I use on a CVD 0 min 2000 average and 2520 maximum the quality is far less good than using 1300 minimum 2000 average and 2520 maximum. The average and the maximum value is the same, so it is obvious that the quality degration comes from the minimum value. And I have tested all the TMGPenc version untill version 12 to the current. Always the same results... So how you do it and I can't? How you make TMPGenc in a simply PAL encoding acting that specific way?

[adam]

Well Satstorm, there is a big difference between getting a SVCD compatible DVD player to play a SVCD with low bitrates dropping down to 800kbits, and getting any DVD player to play an xVCD with bitrates as low as 800kbits. The latter is a completely unsupported format, regardless of how low the bitrate drops, so its difficult to pinpoint the low bitrate specifically as the only problem.

Perhaps dvd players handle low bitrate better in mpeg2, after all I've seen commercial DVDs drop down to under 800kbits. Also, I'm sure dvd players are more leniant with formats that actually support VBR encoding, unlike VCD. If you were to test compliant formats on players which supported them, I wouldn't be suprised if your results were different.

I have always used 0-300 for all my SVCD, CVD, and now DVD encodes and I have yet to find a player which can't play them and I have tested many players.

[SatStorm]

I only mention the Freeze as a plus. Even with xSVCDs using 352 X 288 at a so low bitrate (>800kb/s) I have seen the same problem. I have an extra low CVD average~650kb/s (!) and it is not playable in my standalone (cyberhome 212M), and few others I tested. The same disc was playable of course on other standalones But this is not my point!!!!

My point is that you harm your drive if it is cheap by forcing it read at a so low speed. This is a practical rule if you use a standalone with a cheap drive.
Plus, don't expect good quality with a 1/2 CCIR framesize, if you use TMPGenc with a lower than 1000kb/s value. Set it that low, and you gonna make the final mpeg quality suffer!

Do you have anything to say for those 2 things I mention with your experience?

[adam]

Well, I'm just curious why playing low bitrates would hurt your hardware? How do you know this? The amount of data being fed into the player shouldn't matter as long as it complies to spec, that's what the buffer is for.

All I can say is that CVDs, SVCDs, and DVDs, support extemely low bitrates. Its in the standard, and if a DVD player claims support of any of these formats then it is required to play bitrates these low. I don't doubt that there are players which don't conform to spec, but I have yet to encounter one. I can't speak for xVCD or xSVCD support, because there is none.

I agree with you about the quality, using under 1mbit avg will surely have noticable artifacts at most resolutions, but there will always be some scenes which require less than this ie: credits, so I don't see any problems with using a min of less than 1mbit, as long as your avg and max settings are reasonable, unless of course you are having playback issues.

[ZippyP.]

.....and if the result not suffer from quality decration, I quit my job! And currently is very difficult to find another soon!

Just wanted to compliment the participants of this thread on an excellent and interesting debate. Well done and keep up the good work!

[poopyhead]

@SatStorm

i would think that if the avg. bitrate is reasonable, i.e. around 2 mbit/s, perhaps even higher, that setting a min bitrate to 200-300 kbit/s wouldn't be that harmful to the quality. the encoder will only allocate these low bitrates to scenes that only require these bitrates, i.e. end credits.

[freak_in_cage_10k]

@ satstorm & adam:

i have read your debate with interest

thought i would mension that if you find seftys guide to making a svcd/cvd etc he reccomends using bitrates of about 1000,2000 and 2500 max (approx!) i found this very interesting, and i decided to keep my min to 300, mainly because i hate the idea of the 10 mins of credits at the end of the movie getting 1 meg per second, when they can get about 500kbs and then my 10min action scene increases by about 25%! however, i must confess that i did try an encode at 100,200 and 2500 and i considered the general picture to be a little better, maybe i just watched a low action scene but it was noticeable!!!! however, simply because i dont want the credits to get the high bitrate i think i will stick to 300,2000 and 2500

[poopyhead]

@freak_in_cage_10k

to be accurate of the results, you prolly need to view a longer portion of the movie.

keep in mind that since the avg. bitrate is still 2 mbit/s, if the end credits and slower scenes get lower bitrates (say 500 kbit/s), then other scenes must have higher bitrate (>>> 2 mbit/s) to make the avg. bitrate 2 mbit/s.

i'm sure that the high action scenes would look much better with a lower min. bitrate, while the slower scenes would suffer a little. i guess it's up to you.

[SatStorm]

First of all it wasn't a debate, it was an experience exchange for this matter from 2 long term forum friends and advance users.

Anyway, I only say don't go lower 1000kb/s for TMPGenc, because I do know this encoder well enough after so long time. I can't say the same for CCE or others, but for TMPGenc I am for sure an advance user. This encoder has issues with this matter. It doesn't spread fair the bitrate. And as I said, it is a practical suggestion, based to the released versions untill today. That means that in the next version for example, this can be change. Very unlikely (this situations remains the same until version 12...), but it is always a possibility. And the quality issue maybe is unoticable to most people, but why not talk about it when it is there?
Theory and Practice.... In theory everything is determinded and thereare no any errors. In practice everything are possible! We all know that...

About the speed or the drivers, the role of buffers etc... Yes Ok, but for some strange reason what I mention it happens. Just use a DVD standalone basicly for CD based stuff and soon or later you gonna see that you start having problems when you play DVDs and in some extreme cases, DVD discs turn unplayable! More extreme situation: The drive is dead.
The best way to test this: Do some xVCDs / xSVCDs with TMPGenc and those so low bitrates for your children... You know how they use to watch their movies. Leave them do this a month. Then, after a month, try to play a commercial DVD video to this same standalone. If the disc plays correct, then the DVD-rom manufacture needs a big money donation.
But if you encode with a minimum of 1150, in this example helps the drive.

This 2 things I mention are based on practical objervation. In theory there shouldn't be a problem, but for various reasons things pops up. Or you try to solve them with logic or you try to bypass them. I prefer the second trip, 'cause I'm lazy and this way is easier. And has a 100% success. It is not the solution, but you do your job better.

And this overall conversation is just for the record now. I don't know a single person encode to DVD discs with so low bitrates. Even me, I use 1500 minimum for everything now, just because I don't want to see artifacts in a black screen. The goal is to find a solution, compatible with theory and the practical issues the same time. So any suggestion might help in this direction. Even if it sounds silly or not important. I prefer prevent things than to have to deal with them. I guess anybody wants it that way too.

[adam]

Couldn't have said it better myself SatStorm.

I'll be the first to admit that theory sometimes goes out the window when using TMPGenc, and I'll also be the first to admit that you probably have logged more hours in TMPGenc than I have. I have done alot of bitrate analysis on TMPGenc encoded output, however, and I just haven't come to the same realizations as you, that's all.

As for no one encoding DVDs with minimum bitrates that low? Well, maybe encoding practices vary drastically from region to region, but here in Region 1, plain black credits with white text drop down to about 700kbits-1mbit on pretty much every single one of my commercial DVDs. Other scenes in the movie sometimes drop down as low as 1mbit. It doesn't matter how much bitrate the DVD standard supports, a long fade to black simply doesn't need more than 500kbits, and left to its own devices, an encoder will probably allocate around 1mbit when using such a high avg bitrate, such is common with DVDs. If you watch the movie Equilibrium there is a totally black scene that lasts for 30 secs...the director said that during the premiere the audience thought the projector broke Whether you use 500kbits min, 1500kbits min, or 5mbits min, this scene isn't going to look any different. These things happen in movies, I prefer to let my encoder sort them out, so I put as few limits on its bitrate allocation as possible.

What this all boils down to is, do you trust the encoder? If you do, then there is no harm in using a minimum of 0 because anything that needs a certain bitrate will still get it. In my opinion, if you trust the encoder to analyze your source and distribute your bitrate for you, than you'd have to trust the decisions it makes on the low end of the scale, ie: those scenes that are allocated the least amount of bitrate. In my opinion, if you can't trust your encoder to lower your bitrate where adequate, than you shouldn't trust it to do your bitrate allocation at all, and you should just find a new encoder. After all, its all the same algorithm whether its allocating 500kbits or 5mbits.

However, IF raising your min produces better results to your eyes or bypasses specific playback problems then of course use it. In theory a higher minimum can only hurt quality, but as SatStorm noted, theory isn't always what its cracked up to be, especially with TMPGenc.

I'm still not convinced that low bitrate can harm DVD players, since they are required by spec to play them, and like I said, every commercial DVD I have seen drops below 1mbit at one point or other. I realize you are talking about extended periods of low bitrate, but still, I don't see a difference. I think there are just far too many variables to draw this conclusion, but since I don't have any kids I'll have to put this experiment off for another day.

My general theory regarding your hardware problems/concerns is just that players which support vcd, svcd, and certainly xvcd and xsvcd, are generally of lower quality compared to those that only support DVD, and thus generally break down faster. I know that has been my experience. I went through two Apex's. On the first I only played commercial DVDs, and it crapped out in a year. The second I played almost exclusively VCDs, and it also crapped out in a year. I don't blame my disks, I just blame Apex.

[ZippyP.]

I'm still not convinced that low bitrate can harm DVD players... I think there are just far too many variables to draw this conclusion....

I agree, blaming low bitrate as the cause of DVD player failures seems like a stretch to me. I don't want to denigrate Satstorm's opinion, I'm sure he has far more experience than I. Setting up a reliable way of testing the theory would be very difficult, so I guess we'll never know definitively.

[SatStorm]

I don't win/get something by prooving that I'm right or not in this subject. I just suggest something which I follow myself and I know that others also do for the same reasons I state. The same concept behind. If you don't find this concept correct or you have your doubts, it's okey. I don't say "do this", I say "I suggest this because I (and others) believe this".


About the other thing now for TMPGenc and the correct spreading bitrate....

My source, are DVB transmissions and analogue Captures. Very rare I convert from DVD.
So, my knowledge and experience is based on those sources.

I realise one thing now: When the source is DVD, it is already a top quality mpeg 2 and already has all the intra frames on the scene changes correct.
With the analogue Captures of mine, TMPGenc has to detect the scene changes and add on them Intra Frames. Unfortunatelly, this is not a stronge point of TMPGenc.
The DVB transmissions are also realtime A/D convertions and they suffer from intra - frames at scene changes. DVB transmissions are CQ-Like VBR transmissions, with no time to analyse the source (no buffer technics). The encoding is realtime and thats why the picture suffer from macroblocks! I'm talking here for the stream itself, it is possible to rip the stream "as is" as you know. In short terms, DVB transmissions don't have many intra frames.

So, if I combine Adams knowledge for the subject and my knowledge of the subject, then I just realised that:

With DVD, you have Intra frames which any encoder detects and use when ot encodes. Those Intra frames leads the encoding and prepare correct any encoder for the scene changes.

With Analogue captures /DVB rips, any encoder needs to detect by itself the scene changes to insert those Intra frames...

Hmmm... Just think a bit this. Very interesting objervation....

I think this explains why if I use a higher value as a minimum bitrate I have better results. I have better results because the encoder has to rise less the bitrate between the scene changes, so the result is smoother....

Any thoughts for this?

[ZippyP.]

I don't say "do this", I say "I suggest this because I (and others) believe this".

Satstorm, your manner is refreshing compared to so many others who cannot state an opinion without insulting others. You set an example of respect which we should all emulate.