Best bitrate? CBR or VBR?

[Waldo1967]

I'm using Ulead to create my DVD menus and then extracting as an iso and burning with ImageBurn. I realize Ulead probably isn't the greatest program, but I like it's ease of use and I don't have time to learn something more complicated.

I have some options for encoding. What would be the best for compatibility and stability?

1. Constant or Variable Bitrate
2. Bitrate - 4000, 5000, 6000, 7000, 8000
3. Audio - LPCM, MPEG, or Dolby Digital

I also have the option to do a two pass encode. Would this give better quality at a lower bitrate?

*And yes, I'm burning to quality discs and not to put sticky labels on them.

[lordsmurf]

What kind of content, what resolution, how much do you want to put on a disc?

[Waldo1967]

The content is events, weddings, etc. 720x480 resolution. Created with Premiere 6.5, exported as MicrosoftDVAvi. The amount on the disc of course depends on the length of the event. If I have more than can fit on a single disc, I'll make 2 or 3. I read here that you shouldn't put more than 4 gigs on a disc. So I'm trying to figure out what is the best bitrate to make the discs compatible and stable. I've had some of my discs come back with people saying they skip or freeze and I'm thinking it could be that my bitrate was too high (8000). I just found out I can edit the bitrate options in Ulead and so I'm trying to find the best balance for quality and compatibility.

[videopoo]

VBR vs CBR will not affect compatibilty. Problems arise when too high a bitrate can overload player buffers causing skips or freezes. IMO 8 is too high. I never go above 7 myself and always use CBR if space is not an issue.

Bitrates spikes are another issue that concerns me. All encoders output them so the lower I can go the better. Basically go as low as you can with a bitrate & picture that makes you and /or your client happy

And always use AC3 unless you or your client absolutely must have uncompressed audio but just make sure your video's bitrate is low enough to handle the extra bandwidth that audio is going to tack on. Very few DVDs are produced with uncompressed audio and the ones that are were encoded with expensive encoders which still look good at 4mb/s.

Less is more in DVD land

[edDV]

In general,

1. CBR is often used for high bitrate (Quality). It just records without analysis. VBR is a way to increase picture quality at a given average bitrate. The encoder will adjust bitrate to match detected motion in the scene. For the Mainconcept encoder that ULead uses, two pass increases precision of VBR file size. The first pass analyzes motion, the second pass uses that analysis to encode the video. VBR looses effectiveness at higher average bitrates since there is no headroom. Better to use CBR at high bitrate.

2. Bitrate sets the number of minutes recorded in a given file size or bitrate times seconds equals file size. Other settings being equal, higher bitrates give higher picture quality.

3. LPCM is uncompressed (~1500Kb/s for 16bit stereo). Mpeg audio compression works but is non-standard for NTSC. MPeg can be used for PAL and will probably work for most NTSC players. Dolby Digital (AC3) is standard for NTSC DVD and can store 2-6 channels.

For weddings, try CBR 8000-9000Kb/s or VBR ~8000Kb/s average with AC-3 audio.

[edDV]

I too like CBR for DV camcorder video. 7000Kb/s can work for steady semi-pro camera work. Unsteady video with fast zooms and pans can use more bitrate. I like 7500-8000kb/s.

Jerky video can whipsaw VBR or cause VBR to degenerate into average setting in order to maintain average.

Low light shots (noisy) can benefit from more bit rate.

[daamon]

Following on from edDV's comments... The calculator lower down this page

http://dvd-hq.info/Calculator.html

...will be of use too.

[Waldo1967]

Ok thanks guys. This forum is the best!

So 8000 - 9000 is still ok?! I read somewhere here that 8000 is too high and can cause skipping because poor DVD players have a hard time reading that high. Recently I sent out a video that was only 30 minutes long and I thought I would encode it at 8000 for best quality, and it still only took up 2 gigs so I thought I was safe. The person said it was skipping. However, there were two other factors that may have been the problem . . . I used a sticky label and a cheaper disc. So I searched this forum, read the comments about sticky labels and cheap discs, and bought a disc printing printer. I'm giving the person a Verbatim printed disc today burned at 6000 VBR. We'll see what happens. I was also using LPCM audio, so maybe I should try AC3 as well.

One more thing, should I always stay below 4 gigs per disc, or is it safe to record right to the edge of the disc at 4.3 gigs? I think I know what the answer is going to be.

[Waldo1967]

I also wonder how much of a difference in terms of space there is between CBR and VBR. Say I have 60 minuetes of video . . . with CBR at 7000b/s with AC3 audio that might be what? 3.5 - 4 gigs? But then the same video using VBR would be what? 3.0 - 3.5? Or less? I guess it depends on how much motion is on screen eh?

[manono]

Geez, and you actually charge money for your "expertise" in creating these things? Shouldn't you have learned all this a long time ago?

with CBR at 7000b/s with AC3 audio that might be what? 3.5 - 4 gigs?

Depends partly on the bitrate of the audio. Using DD 2.0@192kbps, I get roughly 3089MB=3.02GB for 60 minutes of video. That's what bitrate calculators do for you.

But then the same video using VBR would be what? 3.0 - 3.5?

Depends entirely on what you choose as your average bitrate for the same 60 minute video. Plus the size of the audio and the muxing overhead.

For what it's worth, I fill my DVD+Rs to the edge. Every one I make is 4075-4080MB=4.37+GB. Never had a problem. And I use the highest max video bitrate I can, frequently 9800kbps. My player plays what it's supposed to. I don't care about someone else's lousy old player that can't handle all DVDs that conform to the DVD specs as far as bitrate requirements go. I can understand, though, if you as a "professional" have to make allowances for your clients' sometimes lousy players.

[edDV]

The skipping may be due to disc media.

[videopoo]

8000 - 9000 is WAY TOO HIGH!!.

Do a test...You won't see a difference from 6-7 to 8-9 will a decent encoder (which is what you should be using if this is a professional gig). Plus your risking overloading a player's buffer..not to mention those bitrate spikes!!

Media is rarely an issue when skipping and freezes occurs. Not to say it doesn't happen but you should always be using quality media anyway.

Never ever max out your bitrate!!!....It makes no sense since the difference in quality is not there.... go low as possible. You always have to consider all the crappy players out there in a professional enviroment.

[edDV]

8000 - 9000 is WAY TOO HIGH!!.

Do a test...You won't see a difference from 6-7 to 8-9 will a decent encoder (which is what you should be using if this is a professional gig). Plus your risking overloading a player's buffer..not to mention those bitrate spikes!!

Media is rarely an issue when skipping and freezes occurs. Not to say it doesn't happen but you should always be using quality media anyway.

I've got DVD players here, both Chinese and name brand that reject certain brands of DVDR media. These tend to be the older players.

[videopoo]

Which brands and which models numbers? These things are always good to know

[lordsmurf]

8000 - 9000 is WAY TOO HIGH!!.

That is not correct.

The DVD spec has a max of 9800 with AC3/DTS or 10080 with PCM. If your player is some cheap Chinese piece of crap, then replace the player, quit making inferior DVDs. Any machine unable to support the full spec should not be carrying the DVD-Video logo.

The only way to get good quality video at 720x480 will sometimes require a bitrate in the 8000-9500 range.

Media is rarely an issue when skipping and freezes occurs. .

That statement is totally inaccurate. Probably 9 out of 10 skipping/freezing problems are due to cheap garbage DVD media. See www.nomorecoasters.com for info on getting yourself some good discs.

[Cornucopia]

8000 - 9000 is WAY TOO HIGH!!.

Do a test...You won't see a difference from 6-7 to 8-9 will a decent encoder (which is what you should be using if this is a professional gig). Plus your risking overloading a player's buffer..not to mention those bitrate spikes!!

Media is rarely an issue when skipping and freezes occurs. Not to say it doesn't happen but you should always be using quality media anyway.

Never ever max out your bitrate!!!....It makes no sense since the difference in quality is not there.... go low as possible. You always have to consider all the crappy players out there in a professional enviroment.

That's another urban myth!

If you're worried about your bitrate "spikes", get BitrateViewer or similar. Or use an encoder that you have good control over --and control it!.

Media can be an issue, even with quality media (because there's such variability in batches, and because not all players' drives have the latest firmware for all kinds of media dyes). And a "good burn" may still have (recoverable) errors, but one where a finicky player's re-read time may get too long and make them "unrecoverable" (aka skipping/freezing). Buffers have been standardized for quite a while, that's a red herring.

I follow the rule of thumb where you MAXIMIZE your bitrate to your available media budget (or bandwidth budget), and my "rejection" rate is <1% of the 1000's that I create. And LOTS of compliments!

Of course, you should test on a number of players (Hard & Soft) both old and new, cheap and fancy.

Scott

[videopoo]

I guess we'll have to agree to disagree..

I know what the spec says..doesn't mean you need to go there...compatabilty over the widest range of player's is key to a successful encode..mind you this is in a professional environment.

I'm not talking about my piece of crap...I'm talking about other people's pieces of crap. You must always consider this when encoding. I can't afford to have people send back my disc's when it won't play becuase I wanted to max out the bitrate.

Check out the bitrates on all disc's at your local store. Rarely will you see an avg. bitrate more than 5500...and these encodes are beautiful!

Been authoring and encoding for DVD for almost 9 years now and rarely is media an issue..maybe back in the day..but now I rarely see any problems with quality media.

I follow the rule of thumb where you MAXIMIZE your bitrate to your available media budget (or bandwidth budget), and my "rejection" rate is <1% of the 1000's that I create. And LOTS of compliments!

Never heard a professional author/compressionist say such a thing...sorry.

That statement is totally inaccurate. Probably 9 out of 10 skipping/freezing problems are due to cheap garbage DVD media

I'm not talking about Garbage Media

Any machine unable to support the full spec should not be carrying the DVD-Video logo.

But they do..and this must be considered. The DVD forum dropped the ball on this long ago

[Waldo1967]

Geez, and you actually charge money for your "expertise" in creating these things? Shouldn't you have learned all this a long time ago?

I never said I charge for my expertise in burning discs. People pay for my expertise in camera operation and editing, of which I have 15 years of experience. Only in the past year have I started burning large quantities of discs and started to have problems.

And judging from the responses, on several threads from people here, there's a lot of differences of opinion, so DVD authoring is still not an easy thing to understand and have a definitive answer for.

But thanks for the help, I guess.

[edDV]

Check out the bitrates on all disc's at your local store. Rarely will you see an avg. bitrate more than 5500...and these encodes are beautiful!

They are in a different world of source quality (film or pro camcorders with trained camera operators, tripods, steadycam, perfect lighing, etc.). Even so they need to work to make 5500 fly. Alot of hand crafting goes on during encoding.

Those who just copy other peoples work can get away with similar bitrates.

Original consumer or prosumer camcorder capture is a world apart in source quality. Added bitrate and CBR are key tools to compensate for shaky camerawork, excessive pans/zooms, poor exposure and noise. The more problems in the source, the higher the bitrate needed.

[videopoo]

They are in a different world of source quality (film or pro camcorders with trained camera operators, tripods, steadycam, perfect lighing, etc.). Even so they need to work to make 5500 fly. Alot of hand crafting goes on during encoding.

Those who just copy other peoples work can get away with similar bitrates.

Original consumer or prosumer camcorder capture is a world apart in source quality. Added bitrate and CBR are key tools to compensate for shaky camerawork, excessive pans/zooms, poor exposure and noise. The more problems in the source, the higher the bitrate needed.

Of course.... But you can't compromise compatabilty just because you somehow think bumping your bitrate to to 9000 will give you a better picture. I agree CBR is a great way to get a better looking stream when space isn't an issue.

[Cornucopia]

...Never heard a professional author/compressionist say such a thing...sorry.

This is straight from the Spruce Encoding Guide (p.68-"Optimizing the Bit-rate/Bit budgeting),

"Optimizing the bit-rate for video encoding is a matter of determining how much storage space is available, then dividing that by the playtime of video you need to put into that space. It's as simple as that.

I'd say they knew what they were talking about regarding professional compression. (and it's pretty much what I said)

BTW, I've ALSO been doing this for almost 9 years.

AFA Hollywood videos with ~5000kbps on them, that's easy...
They have better masters, they use multipass VBR, they're using 24p material with TC flags, they heavily pre-process/NR the material, they do segment-based re-encoding when needed, they tweak the GOPs and Q-matrices, AND this is MAXIMAL for say a 3 hour movie on Dual-layer (with extras).

Scott

[lordsmurf]

I guess we'll have to agree to disagree..

No, we cannot. Your information regarding bitrates is factually incorrect. The spec supports much higher than you say is going to "overload the buffer" (whatever that is supposed to mean). What you really mean is the chipset's ability to decode the information at a fast-enough rate, not a buffer.

You can only "agree to disagree" when it comes to opinions. Your opinion to encode as low as you can, for example. To be honest, I might agree with that under certain conditions. But it cannot be a general rule, it's too broad. That's my counter opinion on that matter.

We actually have several professionals on this site, who work (or have worked for) those "Hollywood" type outfits. I've picked up some good information from them (in private, mostly, not on the forum, mind you), and encoding techniques is one of those topics.

[videopoo]

Yes...I know what the manual says. I was one of the original compressionist to use the MPX3000 at Technicolor in the late 90's. I was also a part of the team which QC'd the European Dinosaurs discs which put a swift end the Meastro's career in DVD....1000's of disc returned due to incompatabilty issues - not in the bitrates we used but Meastro's abstraction layer.

So to say Spruce, which was put out of business years ago for incompatability issues ( on a HUGE scale BTW) & was only a part of DVD when engineers were still learning about incompatability issue themselves, is your defacto guide to encoding for DVD is kinda strange. Also, Im sure your aware manuals are not the place to learn a craft - only a starting point.

That line in the manual is poorly written and wasn't written by a seasoned compressionist anyway - In fact, I know the gentleman who wrote it.

No, we cannot. Your information regarding bitrates is factually incorrect. The spec supports much higher than you say is going to "overload the buffer" (whatever that is supposed to mean). What you really mean is the chipset's ability to decode the information at a fast-enough rate, not a buffer.

You can only "agree to disagree" when it comes to opinions. Your opinion to encode as low as you can, for example. To be honest, I might agree with that under certain conditions. But it cannot be a general rule, it's too broad. That's my counter opinion on that matter.

We actually have several professionals on this site, who work (or have worked for) those "Hollywood" type outfits. I've picked up some good information from them (in private, mostly, not on the forum, mind you), and encoding techniques is one of those topics

I know what the spec says but all players are NOT built the same or up to spec...you must take this into consideration. I would love to hear info from "hollywood" type compressionist and authors who can honestly rebuke what I'm saying. You won't find any because there are none - I work with these people on a daily basis. Bumping up your bitrate to fit the DVD spec's bandwidth availability is just plan wrong. In fact, I have some of the finest compressionist in the world snikering at your responses as I write this.

Anyway...I've given my reasons and facts for this issue... I can't say anymore.

[edDV]

We actually have several professionals on this site, who work (or have worked for) those "Hollywood" type outfits. I've picked up some good information from them (in private, mostly, not on the forum, mind you), and encoding techniques is one of those topics.

I wish they would share more in the forum

My backgound is more in studio and transmission equipment design/marketing. I'm here to learn more about DVD encoding and authoring. I've learned alot so far.

[Cornucopia]

Spruce wasn't "put out by incompatibility issues", it's great software was bought out by Apple so they could revamp DVDStudioPro. They used it as the basis for v2(?) and up. That's one reason why it's so popular now. No compatibility issues to speak of there--many replication houses regard it highly.

If those compressionists you talk of are snickering--maybe they have something concrete to contribute...?

I haven't had the LUXURY of being a "Hollywood-type" compressionist (as I have been living in the midwest), but have been doing Industrial/Corporate/Government titles for years, and if what all you said was true I would have had clients griping left and right about "discs not being playable". Doesn't happen.

Scott

[videopoo]

All I can say is that I was there...I saw people's faces while they were cleaning out they're desks...I remember the lawsuit brought by Sonic soon after for patent infrigements...and I remember Spruce's stock prices hitting the floor.

Spruce's quick fix for the Dinosaur fiasco was the VTS Menu Allocation feature we all know and love in DVDSP but it was too late at that point.

I also remember Apple drooling at the mouth because they offered Spruce a great cash deal - In Apples favor of course.

[GeorgeW]

I also wonder how much of a difference in terms of space there is between CBR and VBR. Say I have 60 minuetes of video . . . with CBR at 7000b/s with AC3 audio that might be what? 3.5 - 4 gigs? But then the same video using VBR would be what? 3.0 - 3.5? Or less? I guess it depends on how much motion is on screen eh?

For CBR, it's probably closer to ~3.2gb. But for VBR, you have be mindful that Ulead's implementation for VBR is to specify the MAXIMUM Bitrate. Some encoders allow you to specify Minimum/Average/Maximum bitrates. Others only allow you to enter one -- it might be for the Average Bitrate, or it might be for the Maximum Bitrate (as in Ulead's case).

So for most Ulead packages (where you only specify one bitrate), encoding VBR at the same bitrate as CBR will yield a slightly smaller file (because the average bitrate is a little lower than the maximum -- I think it defaults to about 90% of the MAX, but that has changed with different packages they offer). NOTE: some of their packages allow you to enter the Min/Avg/Max bitrates, and some can also be "tweaked" to open up an "ADVANCED" encoding option.

Regarding the discussion of bitrates being too high -- I lean towards the side of caution when burning for a wide audience -- I try to keep the total bitrates (Video + All Audio tracks) <= ~7500kbps. But as you can see, there are varying opinions on that matter...

Regards,
George

[Cornucopia]

I'll grant you that the "abstraction" layer is a 2-edged sword, but what you're referring to AFA compability has to do with PGC/Cell navigation. Nothing about bitrates. And you also probably know that alot of those "incompatibility issues" had to do with poor early player implementation. Remember the Matrix white rabbit fiasco?

I wasn't "there" (at Spruce), but did/have often used the v2.95b (last) version of the software (and the MPX3000 hardware), which must have fixed a bunch of those problems you referred to, because ECLIPSE verifyers at replicators have passed them with flying colors.

BTW, that isn't my "defacto guide", but it encapsulates the basic tenets of bit-budgeting. Don't tell me you don't agree with bit-budgeting?...

Tell you what, I'm going to create a multiple title disc that has fast motion scenes/edits, and I'll encode it various CBR bitrates including topping the spec. I'll try it on many players and then get back to you...You might be surprised.
If you're right, I'll tell you. If you're wrong, I'll make an ISO and give you a chance to check it yourself.

Watch out, people here know I've done this before!


Scott

---oh, and I'll make sure to use a tool that doesn't have an abstraction layer.

[manono]

Check out the bitrates on all disc's at your local store. Rarely will you see an avg. bitrate more than 5500...and these encodes are beautiful!

At the risk of piling on... Like so many of your other statements in this thread, that one's wrong as well. To say that you can't tell the difference between a 6000 max bitrate encode and a 9000 max bitrate encode is absurd. To say that the best retail DVDs in the world don't go over 5500 video bitrate is absurd. Do you just make this stuff up?

Here's a bitrate graph (DVD Bit Rate Viewer) for Casino Royale:

http://www.dvdbeaver.com/film2/DVDReviews28/casino_royale.htm

The max shows at just under 9000. Those graphs he uses are zoomed out 3x and it's hard from that to guess the real max bitrate, but I'll just call the max at 8900. Subtract out the 3 audio tracks and you have roughly 1100 less, making the max video bitrate somewhere between 7500-8000, 7800 or so, 41% greater than your assertion. That's very conservative, that estimate. I'm using this as an example as it's a very new release. Another is this one for Rocky Balboa:

http://www.dvdbeaver.com/film2/DVDReviews28/rocky_balboa.htm

Pretty much the same thing. This one for Blood Diamond is somewhat lower:

http://www.dvdbeaver.com/film2/DVDReviews28/blood_diamond.htm

but Warner Home Video is known for being more conservative, and the max video bitrate is probably 7-7500. Theirs always show the max as 7500 in the headers (which, of course, isn't necessarily accurate).

I don't own many new movies on DVD. I checked out the first disc of LOTR-ROTK-EE,and found this:

That's zoomed out 3x. Zoomed in 3x, it's this:

The BitrateViewer graph shows this:

but it can't be trusted as it often gives higher figures than is accurate. This is from one of the chapters and shows (wrongly) the max video bitrate as 8695. DVD Bit Rate Viewer is accurate for all the assets together.

So the max bitrate for all assets and overhead is about 9000. There's a DTS track at 768, a DD 5.1 track at 448, and 5 DD 2.0 tracks at 192. Subtract them all out (and the subs and overhead) and you're left with a max video bitrate of about 6700-6800. And that's a pretty extreme case as they decided to squeeze in way too much audio. Many DVDs have been criticized for that, as it can hurt the video quality. As has been mentioned, Hollywood can do things to prevent artifacts which we may or may not be able to do ourselves, such as smoothing complex scenes, and/or using Adaptive Quantization. I know LOTR-ROTK uses Adaptive Quantization, and it's the first DVD I ever saw that did use it.

I could go on and on. It's also been mentioned that we don't have access to the same equipment as do the big boys. If you're creating videos yourself, it seems to me that you should test (as Cornucopia is doing) on a wide variety of players to see the max video bitrate you can use, and then use it. You should reencode the audio to AC3, so you can use a higher max video bitrate. There's no excuse, in my opion, for ever using PCM WAV audio for homemade stuff, where the extra bits freed up from converting the audio to AC3 can be used to improve the video quality. Also as has been mentioned, if it authors without buffer underruns, and you've been conservative with the max bitrate (and I don't mean 6000, but maybe 9000 plus AC3 audio), if a player is getting stutters and freezes, it's almost certainly due to the media and/or your burning practices (burning at 16x, for example, when you should be using 8x). This also depends on knowing whether or not your encoder honors the max bitrate setting, and if not, knowing how much it's liable to run over and then making allowances for it when setting the max bitrate for VBR encoding, or when setting the bitrate if using CBR encoding.

A bit OT, but if you think the studios even care about being compatible with all players, check out this thread about how Sony's ARccOS "protection" is screwing playback of Casino Royale on many players:

http://www.hometheaterforum.com/htf/showthread.php?t=253669

I couldn't care less, videopoo, what you use for your own encodes. The problem is that people reading your posts might think you know what you're talking about. But, thankfully, there are others here, professionals as well as amateur hobbiests like me, to disagree with you.

[lordsmurf]

There's no excuse, in my opion, for ever using PCM WAV audio for homemade stuff, where the extra bits freed up from converting the audio to AC3 can be used to improve the video quality.

I cannot agree with this either. Sometimes you have to use PCM. Remember that AC3 is compression, and sometimes that compression can alter the audio, especially on very damaged audio quality.

The fix for maintaining video quality is to obey the spec, and then to split to as many discs as needed, and/or use DVD DL media.