Current recommendation regarding fMP4-HLS setting?

[raulo1985]

Hi:

Since there’s has been changes regarding the use of native HLS player vs hls.js in the case of WebOS (the client I use the most), I wanted to know what’s the current official recommendation when it comes to the prefer fMP4-HLS and use shorter segments settings.

I understand that there’s a bug with the WebOS client that generates playback issues when enabling fMP4-HLS, but leaving it disabled means fallback from DV to HDR and apparently it also can produce some playback issues. I understand also that the use shorter segments can mitigate the issues if you need fMP4-HLS enabled, but only to certain extent (I’ve read that stuttering still occurs, and loading times are increased).

I know that it probably comes to a per device trial and error configuration, but what would be the current official recommendation, specially since the last JF update the use of hls.js was reverted in favor of the native player?

I’ve read contradicting info. The most common suggestion I’ve read in the case of WebOS is to leave fMP4-HLS disabled and accept the Dolby Vision trade off, or accept some stuttering and some mitigated playback issues if you need DV and leave the setting enabled with the use shorter segments also enabled.

Questions:

1) Most threads I’ve read suggest to leave fMP4-HLS enabled for most clients to have better HEVC and AV1 support. Besides most likely losing DV, what else could you sacrifice while disabling that setting?

2) There’s supposed to be a bug when using fMP4-HLS with LG native player and since a long time I’ve read that you should always leave it disabled when it comes to WebOS, but recently I’ve seen posts where they say that the current recommendation is to leave both that setting and use shorter segments enabled, to avoid stuttering. What’s the experience with that setup? Is the stuttering really mitigated with shorter segments, and does disabling fMP4-HLS improves playback that much? In other words, when it comes to stability and lack of stuttering/black screens/infinite loading times, when not using DV, disabling fMP4-HLS really improves playback that much? Seems like a setting that you almost always want to leave enabled, but not if it comes with too much stuttering.

3) I’m not the one to question the team decisions, but what would be the reason to discard the idea of having a toggleable setting to decide native player or hls.js only in WebOS? I mean, I understand that the main goal is that playback always works out of the box without much user intervention, but imo there are cases when flexibility is needed (like the use shorter segments settings. I don’t see why that setting is acceptable and the other isn’t). I ask this because I own a C1, and playback was a lot better with hls.js in my case. With native player I have frequent stuttering, infinite loading times, and movies freezing randomly. I modified the code to undo the hls.js reversion (enabled it for browser.web0s and let the server transcode the ac3 audios to aac) using the last master, and playback is back to normal again.

What I mean is that, apparently, WebOS is a mess and every model seems to be a living creature of its own, so I doubt, as much as the main goal is to leave the least amount of technical settings available for the average user, that (unless LG patches things up) you will have all the WebOS users without experiencing issues if you don’t leave some necessary “hacks” available (for example, if there wasn’t a shorter segments setting specific to WebOS, probably fMP4-HLS (and DV) wouldn’t be usable). When the hls.js commit was merged, many started to suffer from playback issues specially when it comes to DV, but when it was reverted, it kind of broke the playback of most movies for other users. Until Lg patches its player, I don’t see a better solution than to leave the decision of using hls.js to the user. Until then I’ll just have to modify the source to use hls.js, I don’t mind that, but surely most of the users don’t know how to build from source. Just a thought.

4) If leaving fMP4-HLS disabled improves playback and only sacrifices DV, does it make sense to leave it disabled while enabling use shorter segments? Is that setting still useful when not using fMP4-HLS?

5) Should I leave fMP4-HLS enabled for every other client besides WebOS? Is that recommended for the iOS official app and JMP?

I’ve read a lot regarding this topic, but like I said, I’ve found contradicting information, so I prefer to ask here. Thanks in advance!

[oligopol]

Hi, I've only been using it since 10.10.9, but since then I've been having problems with DV and playback on my LG B4. I use the native WebOS App, and at first I always wondered why it defaults to HDR instead of Dolby Vision, until I noticed in some forum posts that I have to enable the two settings for fMP4-HLS in order to play DV. However, there are still some titles in my library that stutter a bit, sometimes from the beginning, sometimes only after 45 minutes. Since 10.11.3, I had to deactivate the fMP4-HLS setting again because otherwise nothing would play at all. Now it obviously works “out of the box",but unfortunately the stuttering remains. Really frustrating.

[raulo1985]

Hi, I've only been using it since 10.10.9, but since then I've been having problems with DV and playback on my LG B4. I use the native WebOS App, and at first I always wondered why it defaults to HDR instead of Dolby Vision, until I noticed in some forum posts that I have to enable the two settings for fMP4-HLS in order to play DV. However, there are still some titles in my library that stutter a bit, sometimes from the beginning, sometimes only after 45 minutes. Since 10.11.3, I had to deactivate the fMP4-HLS setting again because otherwise nothing would play at all. Now it obviously works “out of the box",but unfortunately the stuttering remains. Really frustrating.

Yeah, fMP4-HLS is necessary for DV support and Webos native HLS player is known to be buggy with that container. The shorter segments settings mitigates the stuttering, but it persists (not much, but noticeable). And with fMP4-HLS disabled you lose DV support. You had to disable fMP4-HLS on 10.11.3 because JF-Web 10.11.2 was using hls.js in the case of WebOS, and that was reverted on 10.11.3 to the WebOS native player (which is known to be buggy when enabling fMP4-HLS).

My experience with my C1 has been a little weird with these settings, that's why I don't think it's a bad a idea to add a toggeable setting to enable or disable hls.js.

My experience so far with 10.11.3 - 10.11.4 (for context, I only have a few DV movies, so solving issues with DV is not a priority to me):

WebOS native HLS player:

- DV with fMP4-HLS enabled and shorter segments disabled: a lot of stuttering, not acceptable.
- DV with fMP4-HLS enabled and shorter segments enabled: less stuttering, but still present (and with higher bitrates it becomes not acceptable).
- Not DV with fMP4-HLS enabled and shorter segments disabled: little stuttering, some playback issues still present (mostly with fast forward).
- Not DV with fMP4-HLS enabled and shorter segments enabled: a little better, but still have fast forward issues.
- DV with fMP4-HLS disabled: fallback to HDR and, surprisingly (since it's the official recommendation for WebOS native HLS player), I have a lot of issues. Stuttering, infinite loading, and movies not loading at all or freezing.
- Not DV with fMP4-HLS disabled: same as before, a lot of issues.

hls.js (haven't tested with DV yet):

- fMP4-HLS enabled and shorter segments disabled: little stuttering, no playback issues.
- fMP4-HLS enabled and shorter segments enabled: my best setup. Almost no stuttering (only a little with high bitrate movies), no playback issues.
- fMP4-HLS disabled: a lot of issues, infinite loading, fast forward issues, and the movie freezes a lot.

So, in my case (C1), apparently no combination of settings can make the experience acceptable while using the WebOS native player, and disabling fMP4-HLS in my case doesn't solve anything (in fact, it makes it worse). Hls.js improves things a lot, and when I use it with both fMP4-HLS and shorter segments enabled, playback is smooth and haven't experienced freezing.

So, for now, since JF-Web code changed and now it uses native HLS player, I'm building from source to enable hls.js for WebOS. With the current release I haven't been able to solve the issues without using hls.js. Idk if there are many cases like this, but if that's the case a toggeable setting for enabling hls.js would be nice and some users like myself would bennefit from it.

I agree with the concept of trying to leave the least amount of technical settings to the user and have a good experience out of the box, but apparently with WebOS that won't be possible until they fix their player. Shorter segments is an example of a technical setting that couldn't be avoided because without it using fMP4-HLS causes a lot of stuttering, I don't see why the use of hls.js couldn't be another one just for WebOS. There are simply too many different setups with different behaviors, and with different results depending on those settings. Hopefully LG improves things, but I wouln't count on it for a while, and a good workaround could be leaving the choice of using hls.js or the native player to the user. Surely @timitt would agree with me on this one.

Just my experience, though.