10 Replies Latest reply on Feb 22, 2011 6:46 AM by adninjastrator

    Encoding video at a larger size

    Red Rojo

      Given:

       

      • I encode video at 600kbps
      • I set the video to display by default at 448x336 (4:3)
      • Users can set the video to display at full screen (let's say full screen = 1280x960)
      • I can only provide one video resolution to cover all scenarios

       

      Is there any logic to encoding the video for the larger size of 1280x960? Am I wrong in thinking:

       

      • Video encoded at 1280x960 and displayed at this size will look better than video encoded at 448x336 and enlarged to 1280x960; and
      • There will be minimal difference between video encoded at 1280x960 (and shrunk to 448x336) and video encoded at 448x336.

        • 1. Re: Encoding video at a larger size
          612wharfavenues Level 1

          Downscaling will always look better than upscaling, however even if you play a larger movie back at a smaller size, it will still take the processing power as you would playing it at full res. Make sure a single core can handle it.

          • 2. Re: Encoding video at a larger size
            Red Rojo Level 1

            Thank you again.

             

            ". . .  still take the processing power as you would playing it at full res . . ."

             

            Yes (I think I understand).

             

            Just to be sure . . . I won't change the bitrate for each case -- just the resolution of each encoded video. I'd keep the same bitrate (600kbps) for both 1280x960 and 448x336. So, the computer processing needs should be the same, right? My goal is really to optimize (as best I can) the appearance at 1280x960, and assume the differences at 448x336 will be negligible. Make sense?

             

            Maybe I should just test it.

             

            ". . .single core . . ."

             

            What's this? Standard processor in the viewer's computer?

             

             

             

             

             

             

            Stephen Coren

            corenDesign, Inc.

            Design • Web Development • Video Production

             

            617-694-5186

            http://www.stephencoren.com

            scoren@stephencoren.com

            • 3. Re: Encoding video at a larger size
              612wharfavenues Level 1

              Actually bitrate has nothing to do with processing power, and everything to do with disk bandwidth. Even the slowest fullest harddrive (they get slower as they fill up) can handle 20MB/s, 60MB/s on average when empty. Tomshardware.com has alot of disk bandwidth tests to look at. Most compression schemes are way way below that, only when using uncompressed does this become an issue.

               

              Resolution ultimately determines processing power, although the complexity of the compression method used can increase that. All methods use a GOP (look it up) method of compression, basically predicting frames based off a previous whole frame. The more predicting it has to do, the more processing, so if your given the option of setting keyframe distance (a keyframe being the I frame in a GOP), then less will be less processor intensive, albiet less compressed and larger in size. It all depends, and you'd have to run a series of tests to see if the difference in processing is worth the increase in size.

               

              Single core processors are extinct, except in low end computers which many people tend to hold onto for as long as possible. Assume everyone using IE is using a single core processor (p4 3GHz). Its up to you whether you want to include the lowest common denominator.

              • 4. Re: Encoding video at a larger size
                Red Rojo Level 1

                Hmm. Thanks for the thoughtful explanation. Unfortunately, most of it's above my head. But maybe a test I just did relates to what you're describing.

                 

                I have a :30 animated opening with music.

                 

                I encoded it at 600kbps and 448x336. When I play the Flash video, it stutters, both at 448x336 and at full screen.

                 

                I next encoded the same sequence at 600kbps and 640x480. When I play this clip at 448x336, it's very smooth, no stutter. Same when I play it full screen.

                 

                I'm not playing the clip from the Internet (yet). I'm playing it from my computer. And wondering why I'm seeing the stuttering.

                 

                Does this have anything to do with what you're trying to explain to me?

                 

                Also, I've always left key framing on auto. OK practice, or not?

                 

                 

                 

                Actually bitrate has nothing to do with processing power, and everything to do with disk bandwidth. Even the slowest fullest harddrive (they get slower as they fill up) can handle 20MB/s, 60MB/s on average when empty. Tomshardware.com has alot of disk bandwidth tests to look at. Most compression schemes are way way below that, only when using uncompressed does this become an issue.

                 

                Resolution ultimately determines processing power, although the complexity of the compression method used can increase that. All methods use a GOP (look it up) method of compression, basically predicting frames based off a previous whole frame. The more predicting it has to do, the more processing, so if your given the option of setting keyframe distance (a keyframe being the I frame in a GOP), then less will be less processor intensive, albiet less compressed and larger in size. It all depends, and you'd have to run a series of tests to see if the difference in processing is worth the increase in size.

                 

                Single core processors are extinct, except in low end computers which many people tend to hold onto for as long as possible. Assume everyone using IE is using a single core processor (p4 3GHz). Its up to you whether you want to include the lowest common denominator.

                >

                • 5. Re: Encoding video at a larger size
                  jvonmutius

                  If you're not sure if you should leave Key Framing at auto, then you should leave it at auto.

                   

                  You say the smaller video was stuttering, while the larger was not. Were they both the same frame rate? Were they the same in every way except resolution? Also, did you play back the videos in a player or inside your SWF?

                   

                  Can you code your player to load the 448x336 video by default and if the user clicks full-screen, it loads the larger version? That's how YouTube does it now.

                  • 6. Re: Encoding video at a larger size
                    612wharfavenues Level 1

                    I ran into this stuttering problem not to long ago. I was exporting through after effects and it secretly changed my framerate to 30fps (it was 24fps native). Its key that you maintain the same settings throughout the process, else something will go wrong. Lessing the keyframes helped with it, but it shouldnt be a problem if its encoded properly.

                     

                    What browser/program are you playing it through? Do they all stutter?

                    1 person found this helpful
                    • 7. Re: Encoding video at a larger size
                      Red Rojo Level 1

                      Might have been an issue with movie dimensions. I found an error in the size I set for the movie: I encoded at 448x336 but mistakenly set the display size at 443x336. Might have had something to do with it. Certainly seems to play better, at 448x336 since I adjusted the size.

                       

                      That doesn't explain why it stutters at full screen (say 1280x960).

                       

                      The other thing I think I am seeing is encoding (600kbps) and playing at 640x480 seems to produce a video that plays the smoothest. If I encode at the same bitrate and size, but play it smaller or bigger, it seems to stutter. If I encode at the same bitrate but a different size, it seems to stutter whether played at 100% or not. Don't know why.

                       

                      Haven't done enough testing. Safari, IE. JWPlayer is the Flash player.

                       

                      Thanks for your comments.

                      • 8. Re: Encoding video at a larger size
                        612wharfavenues Level 1

                        My experiences is that if you're not youtube or vimeo, your video is going to stutter on any browser. There's something they do with all their billions of dollars that allows for flash video to play smoothly that you cant get relying on just the browser. At least thats what ive found with firefox, opera seems to handle video pretty well given they use software rendering. I wouldnt expect anything from ie.

                        1 person found this helpful
                        • 9. Re: Encoding video at a larger size
                          Red Rojo Level 1

                          Let me back up a bit. Understand: my "testing" isn't very scientific. That said:

                           

                          Key framing is left on default, auto.

                           

                          Frame rate could have been an issue. Normally I leave it at "current." As I recall, in some tests, I may have fiddled with it, setting it at 30. And I always set up my FC projects for "All Rates," which I had assumed was 29.97 for my DV video -- but you've got me thinking, so I'll double check on that.

                           

                          I typically use a player to play the movies, though the scalability of swf is attractive -- mostly I don't use it because I don't like the "horsey" scalability of the player controls. I'm currently using JWPlayer. I do code the video player to play encoded 448x336 at 448x336 with an option to click and play full screen, nothing in between.

                           

                          I appreciate all the advice I've gotten here. It's helping me get a better sense, too, of the process.

                           

                          It's frustrating, however -- there's no standard reference, so much to learn, so many factors that can influence playback, continual change in production tools and techniques, a constant learning curve.

                           

                          I come from the day when I "offline" edited a very tight cut of my video (paper lists!), hired an editor at a post-production facility, and let him/her assemble the duplication master. All the technical stuff was handled by a pro, so it came out perfect. They had all the tools, the "toys," the bells and whistles -- that was the game those companies played (and often lost big at). Now it's individuals, like us, who play the (time and money) game of hustling after the latest "toys" and tools to do our jobs. Nothing really changes, just shifts.

                           

                          I'm now, as probably all of you, creating the "duplication master" myself, admittedly lacking in know how, tools and resources, hunting for that perfect result. As most pros do now, I'm learning stuff as I go, using available/affordable tools, but lacking firm ground rules. I can't tell if the problems I encounter are me, the tools, the procedures, the delivery environment, or what!

                           

                          Anyway, maybe I'm shooting for something unattainable, as 612wharfavenues points out in his last post -- perfection requires lots of $$$ and resources. "Never the same color" doesn't look like much of a problem, does it?

                           

                          A little venting, but all your advice is very helpful. Thanks.

                          • 10. Re: Encoding video at a larger size
                            adninjastrator Level 4

                            I have followed this thread for some time now and it seems that possible solutions have been all over the board.... but sounds like none have hit the target yet.

                            I for one would like to see the actual video file... is there something wrong with it, is the delivery method a problem... what exactly do you mean by "stutters"??

                            Is the problem the video itself, the delivery, or the machine playing it???

                            Post a link to the actual video and get a few more eyes on it... even if that means setting up a temp page.... that will be the best way to get help here from the Forum. On the test page list all the pertinent video file data, bitrate, display size, etc.

                            Best wishes,

                            Adninjastratror