[Mp4-tech] H.264 decoder

[Nabar, Vidyesh]

Chinmay
When you save the file, the text editor is probably modifying the H.264 file. (perhaps something to do with carriage return/ linefeed characters etc)
If you use a binary file editor, you may not have this problem.
Do a binary compare of the saved h.264 file with the original with something like fc (file compare) and check that the 2 files are not the same.
Vidyesh
________________________________
From: mp4-tech-bounces lists.mpegif.org [mailto:mp4-tech-bounces lists.mpegif.org] On Behalf Of Chinmay Bhagwat
Sent: Friday, May 30, 2024 1:28 PM
To: Gary Sullivan
Cc: mp4-tech lists.mpegif.org
Subject: Re: [Mp4-tech] H.264 decoder
I agree that decoding corrupted/incomplete bitstreams  is not possible in the jsvm software.
But, the decoder does not decode even if, for example, the following is done:
   Open the bitstream in some text editor.
   Type a " " (space) somewhere.
   Deleted that <space> just typed.
   Save the file.
   Run decoder.
Why??
Thanks,
Chinmay
On Thu, May 29, 2024 at 7:32 PM, Gary Sullivan <garysull windows.microsoft.com<mailto:garysull windows.microsoft.com>> wrote:
Chinmay et al,
The standard does not specify how decoders should react to incorrectly formatted, corrupted or missing data.  Methods of gracefully responding to such conditions are in the domain of proprietary/non-normative technology. If someone wants to contribute improvements to the JSVM or JM software that would enable it to react more gracefully to messed up input data, such improvement contributions would be welcome (although they would need be prioritized relative to other desirable attributes such as readability, etc., and would obviously be prioritized lower than normative functionality).
Best Regards,
Gary Sullivan
________________________________
From: mp4-tech-bounces lists.mpegif.org<mailto:mp4-tech-bounces lists.mpegif.org> [mailto:mp4-tech-bounces lists.mpegif.org<mailto:mp4-tech-bounces lists.mpegif.org>] On Behalf Of Chinmay Bhagwat
Sent: Thursday, May 29, 2024 1:58 AM
To: mp4-tech lists.mpegif.org<mailto:mp4-tech lists.mpegif.org>
Subject: [Mp4-tech] H.264 decoder
Hi,
I'm having trouble decoding the .264 bitstream with the jsvm decoder.
The decoder aborts if the bitstream file is changed even slightly. Even if the change is removed, the decoder does not decode. It always needs an untouched .264 file.
Why is this so? Is there a way to modify the bitstream and still decode?
Thanks.
Chinmay
________________________________
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