15 Replies Latest reply on Nov 5, 2011 12:14 PM by Jim_Simon

    The best encoding

    Jan pospisil

      Hello Dear friends,

       

      I have spent several days researchng on the best encoding settings for my purpose,

      and out of knowledge of total 0, I got at least somewhere (I think).

      Yet I would deeply appreciate and would be so grateful for any experenced encoding  "Pro" advice.

       

      Here is my point:

      I work with source videos of 1920x1080i, 25ftp, .MOV format, shoot at Cannon 60D,

      my footage and final product is partly travel videos and partly sports, so lot of movement is there (complexity is high).

      I deliver the videos on my website, where my customers are downloading it (I need as low as possible bandwith for which I pay)

      The product which the customers are downloading is averagely 25-30 minutes of duration.

       

      So far my "high quality" download options were not so much of a high quality and I would like to

      provide at least 1280x720 in the final product (after compression).

       

      I should have powerfull machine enough to do whatever with the encoding.

      And I need to reach as much of the video quality as possible, with as much of color preservation as possible,

      and to keep within 400MB of size. As I said my movies are in average 25-30 mins long.

       

      I shoot the videos in h.264 and I think it would be the best to keep this codec in encoding, too. Which gives me .mp4 as a wraper.

       

      I tried following settings in Adobe Media Encoder:

       

      codec: h.264

      1280x720, 25fps, Progressive, NTSC or PAL (I see no difference here), Target and max bitrate both at 2Mbps, VBR 2 Pass, level 3.2, pixel asp.ratio:square

      audio AAC, 64kbps, 48khz


       

      These settings give approx 380MB of 25minutes of video, which seemed to work fine for my purpose when doing hit n' try, yet I would like (again) to ask a Pro for an opinion on that,

      how it would work with the colours, etc. in practice for the audience? Could I somehow gain a little more of quality within the boarder of 400MB...?

       

       

      I would also like to ask, what exactly do I gain by higher bitrate in practise? Of course I see that the quality is higher and it means the data flow per sec., but how does it effect the footage in practise?

      I hope I don't pose to silly questions which might be easily googled by others. If I am totally wrong somewhere, please tell.

       

      Thanks a lot

      Best wishes!

        • 1. Re: The best encoding
          Harm Millaard Level 7

          Duration x Bitrate (quality) x Framerate = Size.

           

          If your limit is say 400 MB, and the quality is not good enough, lower duration or framerate, since bitrate impacts quality. 400 MB would be nice for a Vimeo clip of around 8 minutes or less, but 30 minutes is stretching it quality wise.

          • 2. Re: The best encoding
            Jan pospisil Level 1

            Thanks Harm,

             

            so do u think that in my purpose the 2mbps bitrate will not be sufficient for consumer viewing? If I would go down from 1280x720 and up from 2mbps the quality would go better? So the framerate by itself doesnt influence the quality?

             

            Thanks

            • 3. Re: The best encoding
              John T Smith Adobe Community Professional & MVP

              Also, the PPro FAQ List http://forums.adobe.com/community/premiere/faq_list has an article on exports

              • 4. Re: The best encoding
                crackwitz

                Higher bitrate usually means better video quality.

                 

                you should increase your "maximum bitrate" to 2-5x average bitrate or average+10, or something on that order (so, 10 Mbit/s would be good). maximum bitrate is an upper bound on bits spent per-frame, which is useful for bandwidth-limited realtime video, or embedded devices with limited computational power. complex frames will get more bits if you allow the encoder to vary the bitrate more. the encoder will aim for your average bitrate by saving bits in simpler frames and using them where they're really needed.

                 

                colors aren't much affected by bitrate, unless you're really squeezing it (think realmedia streams over dialup!).

                 

                also: size [bits or bytes] = duration [seconds] * bitrate [bits/second]. frame rate is no variable in that equation.

                 

                more frames per second does mean fewer bits per frame/difference (for same bitrate), but then, more frames means less difference between frames anyway. 25 progressive sounds good. you could try 50 fps interlaced/progressive if you like a more fluid motion in videos.

                1 person found this helpful
                • 5. Re: The best encoding
                  Harm Millaard Level 7

                  size [bits or bytes] = duration [seconds] * bitrate [bits/second]. frame rate is no variable in that equation.

                   

                  Incorrect!. [Seconds] x [bits/seconds] = [bits].

                   

                  [bits] x [frames/seconds] determines the quality of each frame.

                  • 6. Re: The best encoding
                    Jan pospisil Level 1

                    @Harm

                    "[bits] x [frames/seconds] determines the quality of each frame."

                     

                    Harm do u mean here bits as the size bits or the bits per sec.?

                     

                    I forgot to say that I cannot intentionaly shorten the duration, it just comes the way it is, and that is always in between 20-30 mins.

                    So does it mean that the higher the frame rate the better quality for the eye? If I use DSLR I have heard that best video shot is at 23.975,

                    shall i keep that or do i gain more quality if I increase the framerate? As I understood from the hit n try exports, it doesnt increase the size does it?

                    • 7. Re: The best encoding
                      Jan pospisil Level 1

                      Yes, I have seen all the FAQ's regarding the exports, yet it somwhow doesnt directly answer my questions, and even though i got to know a lot i think, I wanted to ask people who know well enough

                      • 8. Re: The best encoding
                        Harm Millaard Level 7

                        You encode with say 4 Mbps. With 24 frames per second, each frame gets 4/24 Mb allocated. If you INCREASE the framerate to say 60, each frame gets 4/60 Mb allocated, so the quality goes DOWN. If you REDUCE the framerate to 12 frames per second, each frame gets 4/12 Mb allocated. So, the LOWER the framerate, the better the quality of each frame and vice versa. Of course you have to weigh that to the stuttering you introduce when you lower the framerate.

                         

                        Best settings is a matter of trial-and-error and depends completely what looks good to your eyes.

                         

                        PS. Mathematical error in my previous post. It should of course have been [bits] / [frames per second], not multiplication, but division. Sorry to have mislead you.

                        1 person found this helpful
                        • 9. Re: The best encoding
                          Jim_Simon Level 8

                          The only two factors that have any significant impact on file size are duration and bitrate.  You said you can't change the duration, and the current bitrate is getting you pretty close to your max allowed file size.  So there's very little wiggle room there.

                           

                          Things like resolution and frame rate will affect the quality of the encoding (all else being equal).  So a higher resolution frame might not look quite as good as the lower resolution frame, given the same number of bits to encode each frame.  Like wise, the more frames per second, the fewer bits per frame you have.  Here is where things become tweakable.

                           

                          Given primarily (only?) a web distribution, I'd recommend first shooting in a 720 format instead of 1080.  No one's going to notice any difference on the web.  You really need a 50" TV or larger to starting seeing any quality difference between 720 and 1080, and very few people have a 50" computer monitor.

                           

                          Next is the frame rate.  Given a fixed number of bits per second, you'll end up using more bits per frame with fewer frames per second, and mreo bits generally means better quality.  At 720 the standard frame rates are 24 (filmic look) and 60 (video look).  Each frame will probably look better if shot at 24fps, but the issue becomes one of motion.  Shooting at 24 fps, you're limited in the kinds of camera moves you can do well.  Slow pans and steady cameras look best.  Fast moves not so much.  You said your material has a lot of action, so shooting at 60 fps may well be the better alternative, even though it means fewer bits per frame.

                           

                          Shooting at 720 and 30 fps is an option for web distribution, but if you ever plan on going to Blu-ray or broadcast, this option isn't allowed.  It'll have to be converted first.  In addition, 30p has a somewhat unnatural stuttery look and feel.  I've never liked it myself.

                           

                          To sum up, keep the encoding parameters the same.  Change your shooting parameters.  Experiment with 720p/24, 720p/60, and possibly with 720p/30.  Shoot some test video of the same subject in all three modes.  Encode each test using the same parameters you're using now.  See which one serves the subject matter best.

                          • 10. Re: The best encoding
                            Jan pospisil Level 1

                            Thanks Jim,

                             

                            this really helped, seems like Harm explained a lot in cube and you made me imagine it even easier:)

                            Well, I also was thinking when I encode to 720 at the end, why the hack should I shoot in 1080? Really is there some point, unless I want to use the footage for full HD some other day?

                            And is it recommended to shoot with one fps setting and encode in another one? Or is it always better to keep the same setting when shooting and later encoding? Say I shoot in 60fps, but decide I want to do the delivery this time in 24 and next time in 60...would there be a harm to the vid?

                             

                            Thanks a lot guys! Even though I might not change my original setting at all, you help me understand things a lot better:)

                            • 11. Re: The best encoding
                              Jan pospisil Level 1

                              @ Jim Simon

                               

                              maybe my thinking is broken, but one more question arises:

                               

                              Will that affect my final size (shooting directly at 720), or is it only a matter of saving hd drive space? (when keeping captures)

                              I might still keep the 1080 shooting set as we are considering of publishing of dvd's in future, would be viewed on large lcd's at homes...

                              Yet this has not much to do with the settings of encode for the web purposes...as the dvd purpose should be encoded separately.

                              • 12. Re: The best encoding
                                Jan pospisil Level 1

                                Also I have no idea about the encoding software, I have used before the sequence matching settings and then using Windows media encoder for compressing as i we used to deliver in .wmv. But know if we can deliver in mp4, I see no reason of why not to export and do the final encode out of Adobe Media Encoder/Premier Pro directly. Do you see any reason why I shall use another party encoder software?

                                Thanks a lot

                                • 13. Re: The best encoding
                                  Jim_Simon Level 8

                                  You should shoot using the same frame rate you intend for delivery.  The exception is fast or slow motion shots.  Shooting at 24 for 60 delivery will speed things up, shooting at 60 for 24 delivery will slow them down.  Outside of that, shoot and deliver at the same frame rate.  Make up your mind about which frame rate to use before you shoot.  Frame rate conversions are best avoided whenever possible.

                                   

                                  The point of shooting at 720 isn't to save disk space.  The point is to use the available bits on a smaller (but still high-definition) frame.  A larger frame will tend to have more artifacts than a smaller frame at the same bitrate.  If you can't compensate for the larger frame by upping the bitrate, then stick to using the smaller frame, especially when no one will see any advantage of the larger frame.

                                   

                                  720 will go onto Blu-ray as is (if shot at 24 or 60 fps) and will scale down fine for DVD if you intend that for the future.

                                   

                                  Reasons to use external encoders are faster encoding times or better quality.  (Sometimes you get both.)  But it helps to be a bit more experienced with encoding before you go down that route.  For now, you're fine using Adobe Media Encoder.

                                  • 14. Re: The best encoding
                                    Jan pospisil Level 1

                                    Jim. how will I gain more experience in encoding if I keep using AME

                                    only?:) I am in the stage when I have to encode all my videos for last two

                                    years (approx 30 videos of 25mins.) so I would like to do it in the best

                                    way possible at this very moment, without the need of reencoding it in

                                    future. So I suppose, if u say I could gain more from tools like Handbreak,

                                    Super etc..I will at least take a look at it, it cannot be that

                                    difficult:). I will study and turn to you guys i I cannot clear any doubts

                                    in other ways. Thanks a lot guys!

                                    All best

                                     

                                     

                                    2011/11/5 Jim Simon <forums@adobe.com>

                                     

                                    **

                                       Re: The best encoding  created by Jim Simon<http://forums.adobe.com/people/JSS1138>in

                                    Premiere Pro CS5 & CS5.5 - View the full discussion<http://forums.adobe.com/message/4008594#4008594>

                                     

                                    • 15. Re: The best encoding
                                      Jim_Simon Level 8
                                      Jim. how will I gain more experience in encoding if I keep using AME only?

                                       

                                      A lot of reading, and a lot of experimenting.