8 Replies Latest reply on Feb 26, 2011 6:37 AM by Dave R Smith

    'f4v' export bit rate ignored, but 'flv' OK - general bug?

    Dave R Smith

      I have been testing the f4v and flv export options in P.Pro CS5.

       

      If I use a FLV preset, note down the video bit-rate and the audio bit rate, then the exported file comes out the expected file size.

       

      If I use the equivalent F4V preset, the file comes out 2 to 3 times larger than it should.

       

      Test source is 720*576 16:9 avi, 25 fps, length 16 seconds.

       

      Web preset of 900kbps selected:

       

      Output f4v 768*432 using 900 kbs (850 video +48 audio) produces 3694kb file = 1.80 megabits per sec.
      Output flv 768*432 using 900 kbs (804 video +96 audio) produces 1943kb file = 0.95 megabits per sec.

       

      So I have 2 observations:
      1) f4v seems to be inefficient compared to flv - but to keep things simple, I won't compare apples with pears.
      2) For a given data rate (900kbps in this case), that should be the output, regardless of image size, frame rate, index frames etc etc.

       

      I have done a number of other tests on P.Pro for f4v and flv presets which shows f4v to be 2* the file size it should be.
      The preset 'name' reciting 900 kbps ties in exactly with the video/audio components in custom panels, so it's not a case of pre-sets having wrong names.

       

      I have aAdditionally I have done similar tests in encore CS5's new export feature, where f4v is up to 3.5 * bigger than it should be for stated data-rate.
      (Yes, I have ignored the index and swf files etc produced by encore from this calculation).

       

      I am expecting this to be a general bug, so would be interested to know if others encounter same problem, before requesting adobe to fix the software.

       

      Format f4v did not exist on CS2 and seems to be OK on CS4, so this is purely a CS5 question.

        • 1. Re: 'f4v' export bit rate ignored, but 'flv' OK - general bug?
          Jim_Simon Level 8

          Just tried it myself.  Both files came out to be very close to the same size.  My best guess here is operator error.

           

          Further, at that bitrate, the f4v looks a LOT better than the flv.

          • 2. Re: 'f4v' export bit rate ignored, but 'flv' OK - general bug?
            Dave R Smith Level 1

            Thank-you Jim.

             

            Please confirm your test was on PP CS5.

            Are you in UK - 25 fps or USA 30 fps?

            I don't see how trying multiple presets can introduce operator error, and always with the f4v significantly larger.

            I have used same test on CS4 and CS5, CS4 is OK, if actions were down to operator error, the CS4 would produce a like distortion.

             

            Encore provides less options for input parameters, being driven by pre-set, where similar wrong results produced, so 'operator error' does not explain it.

             

            Please advise your source clip info and test media encoder parameters and resulting file sizes, so I can test exactly the same and see if it's any different.

            If you change any custom parameters after selecting preset, please advise me, so i can do same.

            Are you able to test on Encore as well?

            • 3. Re: 'f4v' export bit rate ignored, but 'flv' OK - general bug?
              Jim_Simon Level 8

              I am using PP version 5.0.3.

               

              I am in the US, so testing was done with a 16 second standard definition NTSC DV clip.

               

              Final sizes were 1,860 KB for the f4v, and 1,779 for the flv.

               

              Presets used were the F4V Web 768 x 432 900 Kbps and FLV Web 768 x 432 900 Kbps.  No changes made to either preset.  Both went through AME 5.0.1.0.

              • 4. Re: 'f4v' export bit rate ignored, but 'flv' OK - general bug?
                Dave R Smith Level 1

                Thank-you Jim.

                 

                PP version 5.0.3.

                AME 5.0.1.0

                Good thinking on version number, I just did a small update, following CS5 instalation/update 1 month ago.

                I was already on same version numbers and the 20mb 'extension' update hasn't changed anything.

                 

                I usually export direct ftom PP, haven't got in to the habit of using AME yet, though with new fast pc and small test clips I haven't really needed it, but tried via AME to see if had different results but resulting file is 3706KB (1943 KB via flv).

                 

                The 'expected file size says 1MB (though 2MB would be nearest integer for expected results).

                 

                Importing f4v output back into PP, properties give me:

                ---------------------------------------------------------------

                File Path: D:\adobe_tests\z1e_1_768_432_900.f4v
                Type: MPEG Movie
                File Size: 3.6 MB
                Image Size: 768 x 432
                Pixel Depth: 32
                Frame Rate: 25.00
                Source Audio Format: 44100 Hz - compressed - Stereo
                Project Audio Format: 44100 Hz - 32 bit floating point - Stereo
                Total Duration: 00:00:16:01
                Average Data Rate: 231 KB / second
                Pixel Aspect Ratio: 1.0

                ---------------------------------------------------------------

                 

                I gave it a try with no audio and output is 3597KB, so it's not something wierd in audio codec.

                 

                Your NTSC content being around 25% bigger no doubt means more compression to maintain preset data rate, which is to be expected.

                I don't have any 30 fps content, so did tests using 30fps output, from same preset and same 25fps source.

                 

                I don't have any NTSC frame rate media, but I used a 25fps source/sequence and selected output as 30fps which still resulted in an oversize file, but less drastic at 2.6MB (flv 2273KB for 25fps to 30 fps output, other things equal).

                 

                File Path: D:\adobe_tests\z1e_1_768_432_900_30fps.f4v
                Type: MPEG Movie
                File Size: 2.6 MB
                Image Size: 768 x 432
                Pixel Depth: 32
                Frame Rate: 30.00
                Source Audio Format: 44100 Hz - compressed - Stereo
                Project Audio Format: 44100 Hz - 32 bit floating point - Stereo
                Total Duration: 00:00:16:01
                Average Data Rate: 165 KB / second
                Pixel Aspect Ratio: 1.0

                ----------------------------------------------------------

                 

                There is little more I can think of to check as the mysterious bit is in the black hole of dll's.

                 

                A few more cross checks please Jim:

                I am on win7 pro 64 bit.

                Codec on output for f4v preset is Mainconcept H.264 Video.

                • 5. Re: 'f4v' export bit rate ignored, but 'flv' OK - general bug?
                  Jim_Simon Level 8

                  Here's what mine showed.

                   

                  File Path: F:\Temp\Opening.f4v
                  Type: MPEG Movie
                  File Size: 1.8 MB
                  Image Size: 768 x 432
                  Pixel Depth: 32
                  Frame Rate: 23.976
                  Source Audio Format: 44100 Hz - compressed - Stereo
                  Project Audio Format: 44100 Hz - 32 bit floating point - Stereo
                  Total Duration: 00:00:15:23
                  Average Data Rate: 116 KB / second
                  Pixel Aspect Ratio: 1.0

                   

                  Windows 7 64 bit Professional.

                  • 6. Re: 'f4v' export bit rate ignored, but 'flv' OK - general bug?
                    Dave R Smith Level 1

                    Thank-you Jim.

                    I was expecting - or hoping, that were on a mac, to explain difference.

                     

                    It's not directly relevant, but is there any reason why you export at 23.976, when source is NTSC, which implies 29.97 or 30 fps.

                    • 7. Re: 'f4v' export bit rate ignored, but 'flv' OK - general bug?
                      Jim_Simon Level 8

                      The source actually is 23.976.

                      • 8. Re: 'f4v' export bit rate ignored, but 'flv' OK - general bug?
                        Dave R Smith Level 1

                        QED - I have found what is wrong - tracks which have 'toggle output' set to 'off' - blind video tracks and muted audio tracks are being included somehow in the process. (Thank-you Jim, your different findings gave me the tenacity to try different tests, so it did help to resolve).

                         

                        My test sequence comprised of 5 avi files 'stacked', with only the top track set with visibility on and it linked audio set 'on'.

                        I switched to a different sample clip 13 secs long - in case my 16 sec sample was dodgy.

                         

                        With this 13 sec sample and 4 underlying blind/muted tracks it produced f4v 768 432 900kbps files of around 1541kb (=930kbps) so correct.

                        I unlinked the video/audio components of the blind/muted underlying tracks and deleted 1 component at a time, either just the video or just audio and found each made a reduction to final file size. For example 1 video component (without its audo) deleted made about 300kb less.

                         

                        So the encoder is wrongly grabbing disabled tracks, but when it does it's only adding 20% to file size - not doubling.

                         

                        Imbedding the sequence to be exported within another sequence from which to do the export does not get round this bug, so my conclusion is:

                        When exporting to F4V, only use a flat file source, if it is linked or imbedded elsewhere, then those linked assets must be flat files.

                         

                        Returning to encore, my timeline is the p.pro time line dynamically linked.

                        Rerunning the encore build with the p.pro blind/muted tracks deleted produces a much smaller file -and comparing flv versus f4v, f4v is 7% larger on my preset test, but quality is noticably better. But flv versus f4v on quality/functionality is another debate - my thread is about the encoder not producing results as per its parameters.