What version of Hls.js are you using?
v1.6.15
What browser (including version) are you using?
Chrome 146.0.7680.178 (Official Build) (arm64)
What OS (including version) are you using?
macOS 26.4 (25E246)
Test stream
No response
Configuration
{
"debug": true,
"enableWorker": true,
"lowLatencyMode": true,
"backBufferLength": 90
}Additional player setup steps
No response
Checklist
Steps to reproduce
Example fragment parts:
I -> D -> I -> D -> D -> D
Here is an example of mid "independent" part that does not start with IDR:
-----+-----+------+------------+------------+----------+----------------------------------------------
Part | Pkt | Type | Rel PTS | Rel DTS | CTS | Label
-----+-----+------+------------+------------+----------+----------------------------------------------
1 | 0 | IDR | 0.050000 | 0.000000 | 0.050000 | <-- Part 1 start | IDR KEYFRAME | GOP begins here
1 | 1 | P | 0.183333 | 0.016667 | 0.166666 |
1 | 2 | B | 0.116667 | 0.033333 | 0.083334 |
1 | 3 | B | 0.083333 | 0.050000 | 0.033333 |
1 | 4 | P | 0.066667 | 0.066667 | 0.000000 |
1 | 5 | B | 0.100000 | 0.083333 | 0.016667 |
1 | 6 | B | 0.150000 | 0.100000 | 0.050000 |
1 | 7 | B | 0.133333 | 0.116667 | 0.016666 |
1 | 8 | B | 0.166667 | 0.133333 | 0.033334 |
1 | 9 | P | 0.316667 | 0.150000 | 0.166667 |
1 | 10 | B | 0.250000 | 0.166667 | 0.083333 |
1 | 11 | B | 0.216667 | 0.183333 | 0.033334 |
1 | 12 | P | 0.200000 | 0.200000 | 0.000000 |
1 | 13 | B | 0.233333 | 0.216667 | 0.016666 |
1 | 14 | B | 0.283333 | 0.233333 | 0.050000 |
1 | 15 | B | 0.266667 | 0.250000 | 0.016667 |
1 | 16 | B | 0.300000 | 0.266667 | 0.033333 |
1 | 17 | P | 0.450000 | 0.283333 | 0.166667 |
1 | 18 | B | 0.383333 | 0.300000 | 0.083333 |
1 | 19 | B | 0.350000 | 0.316667 | 0.033333 |
1 | 20 | P | 0.333333 | 0.333333 | 0.000000 |
1 | 21 | B | 0.366667 | 0.350000 | 0.016667 |
1 | 22 | B | 0.416667 | 0.366667 | 0.050000 |
1 | 23 | B | 0.400000 | 0.383333 | 0.016667 |
1 | 24 | B | 0.433333 | 0.400000 | 0.033333 |
1 | 25 | P | 0.583333 | 0.416667 | 0.166666 |
1 | 26 | B | 0.516667 | 0.433333 | 0.083334 |
1 | 27 | B | 0.483333 | 0.450000 | 0.033333 |
1 | 28 | P | 0.466667 | 0.466667 | 0.000000 |
1 | 29 | B | 0.500000 | 0.483333 | 0.016667 |
1 | 30 | B | 0.550000 | 0.500000 | 0.050000 |
1 | 31 | B | 0.533333 | 0.516667 | 0.016666 |
1 | 32 | B | 0.566667 | 0.533333 | 0.033334 |
1 | 33 | P | 0.716667 | 0.550000 | 0.166667 |
1 | 34 | B | 0.650000 | 0.566667 | 0.083333 |
1 | 35 | B | 0.616667 | 0.583333 | 0.033334 |
1 | 36 | P | 0.600000 | 0.600000 | 0.000000 |
1 | 37 | B | 0.633333 | 0.616667 | 0.016666 |
1 | 38 | B | 0.683333 | 0.633333 | 0.050000 |
1 | 39 | B | 0.666667 | 0.650000 | 0.016667 |
1 | 40 | B | 0.700000 | 0.666667 | 0.033333 |
1 | 41 | P | 0.850000 | 0.683333 | 0.166667 |
1 | 42 | B | 0.783333 | 0.700000 | 0.083333 |
1 | 43 | B | 0.750000 | 0.716667 | 0.033333 |
1 | 44 | P | 0.733333 | 0.733333 | 0.000000 |
1 | 45 | B | 0.766667 | 0.750000 | 0.016667 |
1 | 46 | B | 0.816667 | 0.766667 | 0.050000 |
1 | 47 | B | 0.800000 | 0.783333 | 0.016667 | <-- Part 1 end | GOP continues into Part 2...
-----+-----+------+------------+------------+----------+----------------------------------------------
2 | 0 | B | 0.833333 | 0.800000 | 0.033333 | <-- Part 2 start (dependent) | same GOP, no IDR
2 | 1 | P | 0.983333 | 0.816667 | 0.166666 |
2 | 2 | B | 0.916667 | 0.833333 | 0.083334 |
2 | 3 | B | 0.883333 | 0.850000 | 0.033333 |
2 | 4 | P | 0.866667 | 0.866667 | 0.000000 |
2 | 5 | B | 0.900000 | 0.883333 | 0.016667 |
2 | 6 | B | 0.950000 | 0.900000 | 0.050000 |
2 | 7 | B | 0.933333 | 0.916667 | 0.016666 |
2 | 8 | B | 0.966667 | 0.933333 | 0.033334 |
2 | 9 | P | 1.116667 | 0.950000 | 0.166667 |
2 | 10 | B | 1.050000 | 0.966667 | 0.083333 |
2 | 11 | B | 1.016667 | 0.983333 | 0.033334 |
2 | 12 | P | 1.000000 | 1.000000 | 0.000000 |
2 | 13 | B | 1.033333 | 1.016667 | 0.016666 |
2 | 14 | B | 1.083333 | 1.033333 | 0.050000 |
2 | 15 | B | 1.066667 | 1.050000 | 0.016667 |
2 | 16 | B | 1.100000 | 1.066667 | 0.033333 |
2 | 17 | P | 1.250000 | 1.083333 | 0.166667 |
2 | 18 | B | 1.183333 | 1.100000 | 0.083333 |
2 | 19 | B | 1.150000 | 1.116667 | 0.033333 |
2 | 20 | P | 1.133333 | 1.133333 | 0.000000 |
2 | 21 | B | 1.166667 | 1.150000 | 0.016667 |
2 | 22 | B | 1.216667 | 1.166667 | 0.050000 |
2 | 23 | B | 1.200000 | 1.183333 | 0.016667 |
2 | 24 | B | 1.233333 | 1.200000 | 0.033333 |
2 | 25 | P | 1.383333 | 1.216667 | 0.166666 |
2 | 26 | B | 1.316667 | 1.233333 | 0.083334 |
2 | 27 | B | 1.283333 | 1.250000 | 0.033333 |
2 | 28 | P | 1.266667 | 1.266667 | 0.000000 |
2 | 29 | B | 1.300000 | 1.283333 | 0.016667 |
2 | 30 | B | 1.350000 | 1.300000 | 0.050000 |
2 | 31 | B | 1.333333 | 1.316667 | 0.016666 |
2 | 32 | B | 1.366667 | 1.333333 | 0.033334 |
2 | 33 | P | 1.516667 | 1.350000 | 0.166667 |
2 | 34 | B | 1.450000 | 1.366667 | 0.083333 |
2 | 35 | B | 1.416667 | 1.383333 | 0.033334 |
2 | 36 | P | 1.400000 | 1.400000 | 0.000000 |
2 | 37 | B | 1.433333 | 1.416667 | 0.016666 |
2 | 38 | B | 1.483333 | 1.433333 | 0.050000 |
2 | 39 | B | 1.466667 | 1.450000 | 0.016667 |
2 | 40 | B | 1.500000 | 1.466667 | 0.033333 |
2 | 41 | P | 1.650000 | 1.483333 | 0.166667 |
2 | 42 | B | 1.583333 | 1.500000 | 0.083333 |
2 | 43 | B | 1.550000 | 1.516667 | 0.033333 |
2 | 44 | P | 1.533333 | 1.533333 | 0.000000 |
2 | 45 | B | 1.566667 | 1.550000 | 0.016667 |
2 | 46 | B | 1.616667 | 1.566667 | 0.050000 |
2 | 47 | B | 1.600000 | 1.583333 | 0.016667 | <-- Part 2 end | GOP continues into Part 3...
-----+-----+------+------------+------------+----------+----------------------------------------------
3 | 0 | B | 1.633333 | 1.600000 | 0.033333 | <-- Part 3 start (INDEPENDENT=YES) | still no IDR!
3 | 1 | P | 1.783333 | 1.616667 | 0.166666 |
3 | 2 | B | 1.716667 | 1.633333 | 0.083334 |
3 | 3 | B | 1.683333 | 1.650000 | 0.033333 |
3 | 4 | P | 1.666667 | 1.666667 | 0.000000 |
3 | 5 | B | 1.700000 | 1.683333 | 0.016667 |
3 | 6 | B | 1.750000 | 1.700000 | 0.050000 |
3 | 7 | B | 1.733333 | 1.716667 | 0.016666 |
3 | 8 | B | 1.766667 | 1.733333 | 0.033334 |
3 | 9 | P | 1.916667 | 1.750000 | 0.166667 |
3 | 10 | B | 1.850000 | 1.766667 | 0.083333 |
3 | 11 | B | 1.816667 | 1.783333 | 0.033334 |
3 | 12 | P | 1.800000 | 1.800000 | 0.000000 | ... 24 dependent frames before IDR (DROPPED)
3 | 13 | B | 1.833333 | 1.816667 | 0.016666 |
3 | 14 | B | 1.883333 | 1.833333 | 0.050000 |
3 | 15 | B | 1.866667 | 1.850000 | 0.016667 |
3 | 16 | B | 1.900000 | 1.866667 | 0.033333 |
3 | 17 | P | 2.033333 | 1.883333 | 0.150000 |
3 | 18 | B | 1.983333 | 1.900000 | 0.083333 |
3 | 19 | B | 1.950000 | 1.916667 | 0.033333 |
3 | 20 | P | 1.933333 | 1.933333 | 0.000000 |
3 | 21 | B | 1.966667 | 1.950000 | 0.016667 |
3 | 22 | B | 2.016667 | 1.966667 | 0.050000 |
3 | 23 | B | 2.000000 | 1.983333 | 0.016667 | <-- last pre-IDR frame (24 frames without IDR!)
3 | 24 | IDR | 2.050000 | 2.000000 | 0.050000 | <-- IDR KEYFRAME | new GOP starts
3 | 25 | P | 2.183333 | 2.016667 | 0.166666 |
3 | 26 | B | 2.116667 | 2.033333 | 0.083334 |
3 | 27 | B | 2.083333 | 2.050000 | 0.033333 |
3 | 28 | P | 2.066667 | 2.066667 | 0.000000 |
3 | 29 | B | 2.100000 | 2.083333 | 0.016667 |
3 | 30 | B | 2.150000 | 2.100000 | 0.050000 |
3 | 31 | B | 2.133333 | 2.116667 | 0.016666 |
3 | 32 | B | 2.166667 | 2.133333 | 0.033334 |
3 | 33 | P | 2.316667 | 2.150000 | 0.166667 |
3 | 34 | B | 2.250000 | 2.166667 | 0.083333 |
3 | 35 | B | 2.216667 | 2.183333 | 0.033334 |
3 | 36 | P | 2.200000 | 2.200000 | 0.000000 |
3 | 37 | B | 2.233333 | 2.216667 | 0.016666 |
3 | 38 | B | 2.283333 | 2.233333 | 0.050000 |
3 | 39 | B | 2.266667 | 2.250000 | 0.016667 |
3 | 40 | B | 2.300000 | 2.266667 | 0.033333 |
3 | 41 | IDR | 2.333333 | 2.283333 | 0.050000 | <-- IDR KEYFRAME | new GOP starts
3 | 42 | B | 2.400000 | 2.300000 | 0.100000 |
3 | 43 | B | 2.366667 | 2.316667 | 0.050000 |
3 | 44 | B | 2.350000 | 2.333333 | 0.016667 |
3 | 45 | B | 2.383333 | 2.350000 | 0.033333 |
3 | 46 | B | 2.466667 | 2.366667 | 0.100000 |
3 | 47 | B | 2.433333 | 2.383333 | 0.050000 | <-- Part 3 end
-----+-----+------+------------+------------+----------+----------------------------------------------
here is the example scenario, the player buffers parts on rendition A, then ABR triggers a switch to rendition B.
The player selects Part 3 on the new rendition (marked INDEPENDENT=YES) in the playlist, appends the new init segment, and loads the part expecting it to produce continuous buffer from its playlist start time (video buffer [58.0–61.633], start time reported from playlist is 61.6). However, the Part 3 contains 24 dependent B/P frames (packets 0–23, PTS 1.633–2.033 relative) before its first IDR keyframe at packet #24 (PTS 2.050 relative). These pre-IDR frames belong to a GOP that started in Part 1 and spans through Part 2, referencing Part 2's P-frames which are not in the buffer since we switched renditions. The SourceBuffer drops those 24 undecidable frames and starts the new buffer range at PTS 62.050 instead of 61.600, creating a ~0.4s gap (61.633→62.050) in the video buffer.
Expected behaviour
playing without freezes and gaps.
What actually happened?
~0.4s freeze and jump over gap via gap-controller.
Console output
Chrome media internals output
What version of Hls.js are you using?
v1.6.15
What browser (including version) are you using?
Chrome 146.0.7680.178 (Official Build) (arm64)
What OS (including version) are you using?
macOS 26.4 (25E246)
Test stream
No response
Configuration
Additional player setup steps
No response
Checklist
Steps to reproduce
Example fragment parts:
I -> D -> I -> D -> D -> D
Here is an example of mid "independent" part that does not start with IDR:
here is the example scenario, the player buffers parts on rendition A, then ABR triggers a switch to rendition B.
The player selects Part 3 on the new rendition (marked INDEPENDENT=YES) in the playlist, appends the new init segment, and loads the part expecting it to produce continuous buffer from its playlist start time (video buffer [58.0–61.633], start time reported from playlist is 61.6). However, the Part 3 contains 24 dependent B/P frames (packets 0–23, PTS 1.633–2.033 relative) before its first IDR keyframe at packet #24 (PTS 2.050 relative). These pre-IDR frames belong to a GOP that started in Part 1 and spans through Part 2, referencing Part 2's P-frames which are not in the buffer since we switched renditions. The SourceBuffer drops those 24 undecidable frames and starts the new buffer range at PTS 62.050 instead of 61.600, creating a ~0.4s gap (61.633→62.050) in the video buffer.
Expected behaviour
playing without freezes and gaps.
What actually happened?
~0.4s freeze and jump over gap via gap-controller.
Console output
Chrome media internals output