Eyevinn / mp4ff

Hello, here are two issues found parsing some test HEVC content...

mp4ff/hevc/sps.go

Line 647 in 2216ac7

for j := byte(0); j < numDeltaPocs; j++ {

Compared to the specification...

The specification uses <= rather than the coded <

Likewise at

mp4ff/hevc/sps.go

Line 649 in 2216ac7

useDeltaFlag := false

The spec suggests this value is actually defaulted to true

Thanks!

@LinkdxTTV Thanks for the reporting this issue. Your findings seem absolutely correct, so I made a PR to fix this problem.

Do you possibly have some HEVC SPS data, that could be added to a test to trigger this issue?

Hello

Here is a sample test including a byte array that failed to parse before but should succeed after this commit

import (
	"testing"

	"github.com/Eyevinn/mp4ff/hevc"
)

func TestSPS(t *testing.T) {
	test := []byte{1, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 255, 3, 32, 0, 1, 0, 25, 64, 1, 12, 1, 255, 255, 1, 96, 0, 0, 3, 0, 0, 3, 0, 0, 3, 0, 0, 3, 0, 153, 53, 2, 64, 33, 0, 1, 0, 40, 66, 1, 1, 1, 96, 0, 0, 3, 0, 0, 3, 0, 0, 3, 0, 0, 3, 0, 153, 160, 2, 128, 128, 45, 22, 141, 82, 187, 34, 186, 173, 146, 169, 119, 53, 1, 1, 1, 0, 128, 34, 0, 1, 0, 8, 68, 1, 192, 36, 103, 192, 204, 100}
	hevcd, err := hevc.DecodeHEVCDecConfRec(test)
	if err != nil {
		t.Error(err)
	}

	spsBytes := hevcd.GetNalusForType(hevc.NALU_SPS)
	if len(spsBytes) != 1 {
		t.Error("expected 1 sps NALU")
	}
	sps, err := hevc.ParseSPSNALUnit(spsBytes[0])
	if err != nil {
		t.Error(err)
	}
	t.Log(sps)
}

Prior to this commit, it should fail with err.EOF

LMK if i can help any way further. Thanks for the fast fix

@LinkdxTTV Thanks! That is very good. I included a variant of your test, and will merge the PR.

Incorrect logic in parsing of HEVC SPS NALU