[Mp4-tech] H.264 decoder

[Chinmay Bhagwat]

Thanks.
And this means that if I use a C++ program to fiddle with the bitstream I
should not have the problem I stated earlier?
On Fri, May 30, 2024 at 10:26 AM, Nabar, Vidyesh <Vidyesh.Nabar patni.com>
wrote:
>  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> 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] *On Behalf Of *Chinmay Bhagwat
> *Sent:* Thursday, May 29, 2024 1:58 AM
> *To:* 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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