0 Replies Latest reply: Feb 4, 2012 1:10 PM by jbwebb13 RSS

    Visual Sample Entry Box question

    jbwebb13 Community Member

      I have been going through f4f files generated by Adobe's f4fpackager. I am writing code to translate from MPEG-2 TS streams directly to .f4f so I need to understand the contents of this file as generated by the f4fpackager. I have read the f4v spec and have already encountered many inconsistencies/errors in that spec.  The latest thing I'm encountering is the following :

       

      Whenever there is a VisualSampleEntryBox in the Sample Description Box, there is the  data defined in the box and then in the "additional boxes" area there are the following bytes :

      00 00 00 32 61 76 63 43 01 64 00 1e ff e1 00 19 67 64 00 1e ac d9 40 a0 2f f9 70 11 00 00 03 03 e9 00 00 ea 60 0f 16 2d 96 01 00 06 68 eb e3 cb 22 c0

       

      which looks like it is a box type but I cannot find what type it is.

       

      It looks like box type : 61 76 63 43 which is avc3.  The description count in the Sample Description box is 1, so this must be one of the "additional boxes as specified for the media type, or encryption". Where do I find the format of that box?  It looks like it could contain NALs from the PES packets, but I'm not sure.  This is not specific to one file, I encountered the same box in an .f4f file generated from an .f4v file. This one had the following bytes :

       

      00 00 00 3a 61 76 63 43 01 64 00 1e ff e1 00 21 27 64 00 1e ac 2c ac 0a 02 db ff 00 2c 00 2d 10 00 00 3e 90 00 0e a6 0e 48 01 79 00 be 6f 7b e0 a0 01 00 06 28 ea c1 83 32 c0 00 00 00 14 62 74 72 74 00 00 2f 20 00 01 79 00 00 01 77 00

       

      What I need to know is, are these NAL's and if so, which ones are required and what else is in the box format?

       

       

      thanks!

      Jennifer