jpeg2000 decoder fails on conformance codestream p0_10.j2k

[Pierre-Anthony Lemieux]

Summary of the bug:
The jpeg2000 decoder fails to accurately decode the p0_10.j2k image from the ​ISO/ITU conformance codestream set:

• the error message bpno became invalid is emitted
• there are significant errors in the lower left quadrant when compared to the reference image c1p0_10-{1,2,3}.pgx

A description of the codestream is available at p0_10syntax.txt

How to reproduce:

ffmpeg -flags +bitexact -i p0_10.j2k p0_10.png
ffmpeg version eef763c7057a7f5f4b7dae7855d07b2a6da8b537

Patches should be submitted to the ffmpeg-devel mailing list and not this bug tracker.

[Balling]

Appears to be different with #5360. That one is a bug in -c:v jpeg2000 native encoder and still decodes bitperfectly.

Also, that is HTJ2K codestreams, no? That patch is not yet apllied: ​https://patchwork.ffmpeg.org/project/ffmpeg/patch/20221215190033.19251-1-etemesicaleb@gmail.com/

[Pierre-Anthony Lemieux]

It is not an HTJ2K codestream. Description at ​https://gitlab.com/wg1/htj2k-codestreams/-/blob/master/descriptions_profile0/p0_10syntax.txt

That one is a bug in -c:v jpeg2000 native encoder and still decodes bitperfectly.

I encountered the bug using the native decoder on the master branch. What do you mean by bitperfectly?

[Balling]

What do you mean by bitperfectly?

The bug there is in the lossless native encoder. Compared to openjpeg that decoder does not warn upon. It is still lossless though.

[Pierre-Anthony Lemieux]

The bug there is in the lossless native encoder.

Two different encoders are not expected to produce the same codestreams.

The native encoder might therefore be good, but create a codestream that results in a different code path in the native decoder, which triggers the bpno warning.

[Balling]

The native encoder might therefore be good, but create a codestream that results in a different code path

It is also creates bigger file. Quite bigger.

BTW, openjpeg triggers this line on the sample ​https://github.com/uclouvain/openjpeg/blob/0bda7188b7b545232a341f1d978b1e4feda46fc2/src/bin/common/color.c#L432

which also blocks -c:v libopenjpeg

Kakadu works the same as openjpeg still, lower left quadrant is indeed different.

[Balling]

the error message bpno became invalid is emitted

Is there any chance this file was created using ffmpeg and thus it is a bug in fixed #5360?

[Pierre-Anthony Lemieux]

Replying to Balling:

the error message bpno became invalid is emitted

Is there any chance this file was created using ffmpeg and thus it is a bug in fixed #5360?

Very unlikely. The file is from the ITU/ISO conformance codestream set and was likely created circa 2002.

[Balling]

​https://patchwork.ffmpeg.org/project/ffmpeg/patch/20240607002549.2259139-1-owatanab@es.takushoku-u.ac.jp/

Nice

[Pierre-Anthony Lemieux]

Fixed at ​https://github.com/FFmpeg/FFmpeg/commit/6f4a95cfb8e6ed97fdd1027251181caded44860f

[Balling]

Fixed in 6f4a95cfb8e6ed97fdd1027251181caded44860f.