[M4IF Technotes] The content in the DecoderSpecificInfo

[Dave Singer]

At 7:37 AM -0700 9/17/02, Heat Mist wrote:
>Yes, I downloaded a few mp4 files that contain video
>and/or audio. I haven't checked all of them. But the
>file called 4videomaxmin_light.mp4 from "MPEG-4
>Content" link on ENST doesn't follow the visual
>DecoderSpecificInfo syntax defined in 14496-2.

I admit I haven't downloaded these, and so the problem might be 
obvious, but it would help if you could tell us in what way they 
don't conform.
>Furthermore, all the ES_IDs in this file are 0, which
>I thought should be different.

ES_ID is always 0 when it is stored in an MP4 file;  it gets replaced 
by the trck_ID when the file is hinted or delivered (this is in the 
MP4 specification).
>If all the others mp4
>files from "MPEG-4 Content" are from the same sources,
>they tend to have the same problem.
>
>Chen
>
>
>--- Jean-Claude Dufourd <Jean-Claude.Dufourd   enst.fr>
>wrote:
>>  Dear Mr Chen
>>
>>  Heat Mist wrote:
>>  > The reason that I am
>>  > asking is that the mp4 files that I downloaded
>>  from
>>  > ENST don't conform to this.
>>
>>  What ? This is impossible. ENST files are compliant
>>  by contruction. ;-))))
>>
>>  On a more serious notes, you seem to be talking
>>  about something strictly
>>  concerning video. Did I understand you correctly
>>  when I reformulate like
>>  this: you have found, in some ENST mp4 files, video
>>  streams for which
>>  the DecoderSpecificInfo syntax did not match your
>>  expectations according
>>  to 14496-2 ?
>>  If so, I need to issue a disclaimer: as much as we
>>  take care in
>>  preparing our mp4 files, our AV streams are only as
>>  good as our video
>>  and audio providers make them. These providers
>>  include a variety of
>>  sources. Please tell me which files so that I can
>>  pass the information
>>  to a video specialist.
>>
>>  Best regards
>>  JC
>>  --
>>  Jean-Claude Dufourd     
>>  @======================================@
>>  ENST, Dept COMELEC             The wing, over the
>>  big rock...
>>  46, rue Barrault        
>>  @======================================@
>>  75013 Paris                Tel: +33145817807    Fax:
>>  +33145804036
>>
>
>
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-- 
Dave Singer
Apple Computer/QuickTime 408 974 3162