implementation of "scaling_list_data" function (hevc_ps.c) does not conform to HEVC standard

[ffmpeg_jhwu]

Current implementation:

if (matrix_id < delta) {

av_log(avctx, AV_LOG_ERROR, "Invalid delta in scaling list data: %d.\n", delta);
return AVERROR_INVALIDDATA;

}

memcpy(sl->sl[size_id][matrix_id],

sl->sl[size_id][matrix_id - delta],
size_id > 0 ? 64 : 16);

if (size_id > 1)

sl->sl_dc[size_id - 2][matrix_id] = sl->sl_dc[size_id - 2][matrix_id - delta];

Suggested implementation:

refMatrixId = matrix_id - delta*(size_id ==3?3:1);
if (refMatrixId < 0) {

av_log(avctx, AV_LOG_ERROR, "Invalid delta in scaling list data: %d.\n", delta);
return AVERROR_INVALIDDATA;

}

memcpy(sl->sl[size_id][matrix_id],

sl->sl[size_id][refMatrixId],
size_id > 0 ? 64 : 16);

if (size_id > 1)

sl->sl_dc[size_id - 2][matrix_id] = sl->sl_dc[size_id - 2][refMatrixId];

[James]

If you think this change is correct then please send a patch to ffmpeg-devel mailing list for review.
See https://ffmpeg.org/developer.html#Submitting-patches for details.

Thanks.

[Carl Eugen Hoyos]

If you don't want to send a patch - made with git format-patch - then please provide a sample that allows to reproduce the issue you see.

[ffmpeg_jhwu]

sample HEVC bitstream

[ffmpeg_jhwu]

Thank you very much for your quick reply.

I attached the sample HEVC bitstream. For the attached sample bitstream, decoded YUV by ffmpeg is different from decoded YUV by HM 16.0 decoder.This is because the parsing of scaling list in the sample bitstream is wrong for current ffmpeg software. Please let me know if you need more information. Thanks.

[Carl Eugen Hoyos]

Regression since 627c044f50da3046809314f7cc742b8a10cf26a1 (analyzed by Mark Thompson).

[jkqxz]

Would it be acceptable for this sample to be added to the ffmpeg regression test suite?

(Patch at ​https://lists.ffmpeg.org/pipermail/ffmpeg-devel/2017-April/210649.html , but would like a regression test.)

[jkqxz]

Fixed in 88a2e4504d1820e717730ff5f5dc0cf4d90cdd6e. A test-usable sample would still be welcome.

[Carl Eugen Hoyos]

Please use the sample attached to this ticket (cut it if possible).

[James]

Replying to jkqxz:

Would it be acceptable for this sample to be added to the ffmpeg regression test suite?

The sample.bin file attached here seems to be the same footage as a bunch of the hevc-conformance samples in the fate suite (see AMVP_C_Samsung), so i'd say it can be added.

Replying to cehoyos:

Please use the sample attached to this ticket (cut it if possible).

It weighs 46k and is 5 frames long, so no need to cut it.

[Carl Eugen Hoyos]

True, sorry!