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Is the "Preferred video resolution" setting working correctly?

Posted: 24 Mar 2017 20:23
by midas02
Hello,

I'm struggling trying to understand the "Preferred video resolution" setting (Tools>Preferences>Input/Codecs). I don't know if this is a known issue, but I couldn't find any recent posts on it, and most of them are related to Youtube.

Now, I've set my preferred video resolution to SD, so I should be getting 540p or 480p streams or lower, if I understood correctly.
But when I'm opening a couple of random HLS livestreams (most of them are French, not sure if they are georestricted), VLC automatically goes for the highest resolution. Usually 1024x576 or 1280x720, so not what I'm expecting to happen.

Here's an example: http://hdfauthftv-a.akamaihd.net/esi/TA ... index.m3u8.
That stream gives me the following playlist:

Code: Select all

#EXTM3U #EXT-X-VERSION:3 #EXT-X-STREAM-INF:PROGRAM-ID=1,BANDWIDTH=231080,CODECS="avc1.66.30,mp4a.40.2",RESOLUTION=256x144 ...-video=152400-audio_AACL_fra_65600_315=65600.m3u8 #EXT-X-STREAM-INF:PROGRAM-ID=1,BANDWIDTH=362520,CODECS="avc1.66.30,mp4a.40.2",RESOLUTION=320x180 ...-video=276400-audio_AACL_fra_65600_315=65600.m3u8 #EXT-X-STREAM-INF:PROGRAM-ID=1,BANDWIDTH=656352,CODECS="avc1.66.30,mp4a.40.2",RESOLUTION=512x288 ....-video=553600-audio_AACL_fra_65600_315=65600.m3u8 #EXT-X-STREAM-INF:PROGRAM-ID=1,BANDWIDTH=933648,CODECS="avc1.77.31,mp4a.40.2",RESOLUTION=704x396 ....-video=815200-audio_AACL_fra_65600_315=65600.m3u8 #EXT-X-STREAM-INF:PROGRAM-ID=1,BANDWIDTH=1622648,CODECS="avc1.77.31,mp4a.40.2",RESOLUTION=1024x576 ...-video=1465200-audio_AACL_fra_65600_315=65600.m3u8
So clearly there are a couple of options for VLC to choose from, other than the one with the highest bandwidth. Is there any reason why this is not happening here? Is this a known issue?

Thanks for you help.

Re: Is the "Preferred video resolution" setting working correctly?

Posted: 25 Mar 2017 10:46
by Lotesdelere
Now, I've set my preferred video resolution to SD, so I should be getting 540p or 480p streams or lower, if I understood correctly.
But when I'm opening a couple of random HLS livestreams (most of them are French, not sure if they are georestricted), VLC automatically goes for the highest resolution. Usually 1024x576 or 1280x720, so not what I'm expecting to happen.
Well, 1024*576 is the highest possible resolution for SD. Anything higher is HD.
The HLS protocol will always try to use the highest resolution according to your available bandwidth, this is one of the main protocol specifications, so this behaviour is normal.

Re: Is the "Preferred video resolution" setting working correctly?

Posted: 25 Mar 2017 17:16
by midas02
Hello Lotesdelere, thanks for getting back to me.

Sorry to be a pain, but I'm trying to fully understand what that setting is supposed to do. Are you suggesting now that it doesn't have any effect on HLS streams? If so, what kind of input is it supposed to have an effect on? I'm failing to understand which other inputs might have a variable bitrate/resolution, other than livestreams and/of DVB input.

Ps: tried other settings as well (360p, and lowest, 240p), none of them has any effect

PPs: coming back on my last remark. Just noticed it has an effect when watching Youtube... although. I had selected SD (576 or 480 lines according to the setting), and I get a 640x360 stream (although 480p was available as well). So that seems to be one case where that setting works. Just a shame it doesn't do it for HLS.

Re: Is the "Preferred video resolution" setting working correctly?

Posted: 21 Feb 2019 15:49
by mederi