Adaptive Streaming for Dolby Vision

[imtiendat0311]

Hi, community,
I'm a newbie trying to learn HLS.js. HLS offers a way to stream adaptive quality based on the bitrate. But apparently, it's only when all media source has the same codec. For example, if I have 3 media sources of different quality but the same codec. The debug tool let me switch each source. But if my playlist has 3 media sources of different quality but different codecs. It's not letting me change the source.
In particular, I have 720p and 1080p sources with the same codec hvc1 ( SDR ), and 4k with dvh1 codec. And based on my testing it let me switch between 720 and 1080 but whenever I switch to 4k dvh1 codec it's just a straight-up error.
I did a test playing only 4k dvh1 and the HLS js appears to play fine with no problem
and I also tried to open the playlist have multiple sources and safari seem to play fine
Here is my playlist m3u8 file

# Created with Bento4 mp4-dash.py, VERSION=2.0.0-639
#
#EXT-X-VERSION:6

# Media Playlists

# Audio
#EXT-X-MEDIA:TYPE=AUDIO,GROUP-ID="audio/ec-3",LANGUAGE="en",NAME="English",AUTOSELECT=YES,DEFAULT=YES,CHANNELS="2",URI="audio/en/ec-3/media.m3u8"
#EXT-X-MEDIA:TYPE=AUDIO,GROUP-ID="audio/ec-3",LANGUAGE="und",NAME="Unknown",AUTOSELECT=YES,DEFAULT=NO,CHANNELS="2",URI="audio/und/ec-3/media.m3u8"

# Video
#EXT-X-STREAM-INF:AUDIO="audio/ec-3",AVERAGE-BANDWIDTH=16561504,BANDWIDTH=55286124,VIDEO-RANGE=SDR,CODECS="hvc1.1.6.L150.b0,ec-3",RESOLUTION=1280x720,FRAME-RATE=23.976
video/hvc1/1/media.m3u8
#EXT-X-STREAM-INF:AUDIO="audio/ec-3",AVERAGE-BANDWIDTH=16593989,BANDWIDTH=83040338,VIDEO-RANGE=SDR,CODECS="hvc1.1.6.L153.b0,ec-3",RESOLUTION=1920x1080,FRAME-RATE=23.976
video/hvc1/2/media.m3u8
#EXT-X-STREAM-INF:AUDIO="audio/ec-3",AVERAGE-BANDWIDTH=18572922,BANDWIDTH=31147663,VIDEO-RANGE=PQ,CODECS="dvh1.05.06,ec-3",RESOLUTION=3840x2160,FRAME-RATE=23.976
video/dvh1/media.m3u8

and the log debug hls.js

73.722 | Media element detached
73.724 | Loading http://localhost:8000/hls/master.m3u8
73.727 | Loading manifest and attaching video element...
73.746 | 3 quality levels found
73.747 | Manifest successfully loaded
73.748 | No of audio tracks found: 2
73.751 | Audio track switching...
73.791 | Media element attached
73.887 | Audio track switched, trying to recover media error.
79.69 | Media element detached
79.691 | The video playback was aborted due to a corruption problem or because the video used features your browser did not support - Media failed to decode
79.695 | Media element attached, trying to swap audio codec and recover media error.
79.886 | Media element detached
79.889 | The video playback was aborted due to a corruption problem or because the video used features your browser did not support - Media failed to decode
79.9 | Media element attached, cannot recover. Last media error recovery failed.
80.054 | The video playback was aborted due to a corruption problem or because the video used features your browser did not support - Media failed to decode, and cannot recover. Last media error recovery failed.
Error
74.742 | Buffer stalled error
80.065 | Buffer append error
80.076 | Buffer append error
80.105 | Buffer append error
80.117 | Buffer append error
80.117 | A media error occurred: bufferAppendError

[robwalch]

Issues related to HDR and CODEC switching are being tracked under milestone 1.5.0 https://github.com/video-dev/hls.js/milestone/53

Manually switching levels to a level with a different video codec should work as long as the codec is supported by the current browser and SourceBuffer.changeType() is supported for the type of transition occurring. That being said addition support checks are needed to correctly evaluate if 4k HDR content is supported and if it is safe to transition to it from SDR or or another codec. If not these variants should be filtered out.

Providing a range of PQ variants is recommended as many clients cannot perform codec switching or SDR to HDR switching without a noticeable interruption. In these scenarios future release would opt to select the optimal starting conditions and remove other options. So, in the future HLS.js might start at HDR and not allow an incompatible downswitch or vice-versa.

The current behavior (v1.3.0) is to start at the default bandwidth estimate, and keep all adaptive selections to the same CODEC set (so if it starts on hevc it will stay on hevc to avoid the chance of errors such as the one you've shared).

[imtiendat0311]

thank you