5 Replies Latest reply on Nov 18, 2012 8:26 PM by Jim_Simon

    Best compression setting 90min movie on Dual Layer DVD


      Okay, I admit, I am a total n00b at this...so sorry if you have to break things down into the most basic terms...


      I am trying to get the BEST quality I can for my adobe Encore project (for ease of calculation, 90min movie and added features).  I was previously getting "exceeds dvd capacity" error in Encore. 


      I have decided to recompress and see what I can do to make it all fit, but first I want to re-evaluate my whole process...


      the ultimate issue comes down to three things (i think)...


      1. CBR v VBR??  what is better and why?


      2. What Data Bit Rate to compress at and why?


      3. Single layer DVD vs Dual Layer DVD?  Which is better and why?


      to begin the discussion, I'll tell you what I "know" and what I think.


      It seems DVD players can only handle a max bit rate of 8mbps so I don't want to go over that and using a Dual layer disc I risk that it may not work on older players....also, the dual layer costs twice as much to duplicate (this sucks but money is not an issue at this point, quality is more important).  From what I have read, constant Bit Rate @ 8mbps will give me the Best possible image... 8 is the max and so to encode at 8 the entire time should be the best..  will i have any issues with this?  This is not an amateur home movie but rather an indie feature film so I want to get the best possible viewable product out to people.  I will have blu-ray questions to come later (thats what we are going to send to festivals).


      any help would be greatly appreciated


      thanks so much...


        • 1. Re: Best compression setting 90min movie on Dual Layer DVD

          I can assist with some of the questions.



          1.  VBR will give better quality for an average amount of bits.  CBR will give the best quality at the MAX bit rates.  If you want your video to have the higest quality bit rate possible, CBR is the way to go.   However, with the highest quality video, it also means more space will be used.


          2.  Data Bit Rate:  The video compression can go from 3 Mbits to 9.2 Mbits.  Data Bit Rate comes down to how good the video looks on the DVD.  So if you were to compare an mpg file of 3 MBits to an mpg file of 9.2 Mbits, the video with 9.2 Mbits is going to look far superior because of the higher bit rate.


          3.  Single Layer vs Dual Layer.  This depends on the type of project you're creating.  A single layer DVD (DVD-5) can hold about 4.38 gigs of data.  A dual layer DVD (DVD-9) can hold about 7.95 gigs of data.  So if you have a larger project with a higher bit rate, dual layer is definitely going to be the best option.  Typically single layer would be used for lower compression rates or if you have a short video project.


          DVD players will, in fact, handle a DVD with bit rate of up to 9.2 Mbits.  And yes, dual layer is more expensive, but they will work with most if not all DVD players.  The only except might be if you have an extremely old player that pre-dates the turn of the century.

          • 2. Re: Best compression setting 90min movie on Dual Layer DVD
            John T Smith Adobe Community Professional & MVP

            My PERSONAL choice is to skip all the manual calculations and let Encore do the work


            I export DV AVI from PPro and open that in Encore... and then set my parameters in Encore (single or dual layer disc, minimum/maximum bit rate) and have Encore use Automatic transcoding to make a "best" fit of video to type of disc

            • 3. Re: Best compression setting 90min movie on Dual Layer DVD
              cfg_2451 Level 2

              Bit rate questions nearly all involve complex answers, because it's not a simple process. It basically comes down to motion in the scene. If you have a static scene, no camera motion, no subject motion (think a slide as part of a presentation), high bit rate is a waste of space. Especially with a long GOP CODEC. That's one extreme.


              On the other end, if you have lots of motion from camera (pan / tilt / dolly move) or subject (movie fight scene) then you need all the bit rate you can get. Especially with a long GOP CODEC.


              Nearly all video is somewhere in between these two extremes. And this is why variable bit rate CODECs were invented. A VBR CODEC uses minimal bit rate where needed, and maximum bit rate where needed. This is an attempt to maximize image quality while minimizing space requirements. And it largely works.


              Since I don't know your video, I suggest you try both CBR and VBR implementations. Play the DVDs and decide what works best for your particular situation. Do use two-pass encoding, and max. render quality.

              • 4. Re: Best compression setting 90min movie on Dual Layer DVD
                ccraine Level 1

                Okay, thanks for everyone's thoughts.




                I totally understand not wanting to waste space on a dvd IF there was extra room.... HOWEVER, a movie at 90min with menus, etc. BARELY fits on a dvd at a 6.8mbps VBR compression rate....


                therefore....why not just fork out the extra couple bucks and just compress the whole thing at 8.0mbps 2pass CBR, slap it on a dual layer and even though there will be parts of the movie that will be higher than necessary, and there will be leftover space on the dual layer dvd.... you will be guaranteed to have the highest quality right?  heavy motion areas and more static areas will all be encoded at 8 and thus, the best....


                am i wrong in thinking this?



                and after some extensive reading and research....Although is says a dvd player can handle 9.8mbps..... it doesnt' seem safe to encode that high because a lot of players can't handle it.... what is everyone else's thoughts?

                I found this:


                Data rate 

                DVD-Video discs have a raw bitrate of 11.08 Mbit/s, with a 1.0 Mbit/s overhead, leaving a payload bitrate of 10.08 Mbit/s. Of this, up to 3.36 Mbit/s can be used for subtitles and a maximum of 9.80 Mbit/s can be split amongst audio and video. In the case of multiple angles the data is stored interleaved, and so there's a bitrate penalty leading to a max bitrate of 8 Mbit/s per angle to compensate for additional seek time. This limit is not cumulative, so each additional angle can still have up to 8 Mbit/s of bitrate available.

                Professionally encoded videos average a bitrate of 4-5 Mbit/s with a maximum of 7–8 Mbit/s in high-action scenes. This is typically done to allow greater compatibility amongst players, and to help prevent buffer underruns in the case of dirty or scratched discs.


                • 5. Re: Best compression setting 90min movie on Dual Layer DVD
                  Jim_Simon Level 9

                  it doesnt' seem safe to encode that high because a lot of players can't handle it.... what is everyone else's thoughts?



                  All players can handle the max bitrate.  The myth that you need to keep it at 7 Mb/s or less comes mostly from people creating bad disks.  If a disk has too many errors, the player will keep trying to read the bad sector for a bit.  That can cause a pause or stutter during playback.  People notice the lower bitrates seem to help, and so assume the player couldn't handle the higher bitrates.  What actually happens is the lower bitrates allow more of the movie to be stored in the buffer, so the rescan doesn't cause buffer to empty.


                  Three tips for successful burning.


                  1. Use high quality media.  Falcon Pro are the best.  Taiyo Yuden and Verbatim are also very good.

                  2. Use good hardware.  Sony/NEC (Optiarc) consistently produce excellent burners (but recently went out of business, so you may have to read some reviews on other models if you can't find one.)  And remember to burn at the disks lowest rated speed.

                  3. Use the best format for that player.  Some prefer -R, some work better with +R.  I had one that worked best with +R/W.