[FFmpeg-devel] API enhancements / broken promises

[Jean-Baptiste Kempf]

On Wed, 17 Aug 2022, at 19:21, Michael Niedermayer wrote:
> a unwise choice. But if someone is against very basic xml or json parsers
> please speak up now and here because its still better to say "no" now than
> after nicolas did the work.

Absolutely against this idea.

Both JSON and XML are very very very difficult to parse in a secure manner.

Doing a simple XML parser and a simple JSON parser might be simple tasks for any decent programmer, doing those parsers is extremely difficult because there are a lot of complex corners cases, even if you take a subset of XML. Unicode, encoding, entities decoding, binary data, languages are not something you can skip, even if you take a subset of XML.

Once you add document validation and DTD, namespaces, recursive XML or XPath/XQuery this makes it a project as big as the whole FFmpeg, and that's why libxml2 is so big.
If you just want DASH and TTML (and maybe fontconfig), you still have to do a large set of features.

And then you need to care about security. It's a difficult problem to fix, and seeing the track record of the security of open source multimedia projects, we should focus on our issues, not adding new ones.


If you believe that you can do a better job than thousands of people paid large amounts of money who spent decades on this problem, then, please do a separate project, host it on git.ffmpeg.org, git.videolan.org or github, and give us a fast streaming API. Please be sure that you validate most test-suites and cornercases too. And fuzz it.

Managing to do that would be an impact probably much bigger than FFmpeg, so don't hesitate. And then FFmpeg will be able to use it, and other projects too.

But for me, until this is ready and battle-tested, it's a hard no..

jb

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Jean-Baptiste Kempf -  President
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