Optimizing new Chromecast preset to increase quality

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Hbortin
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Joined: Sat Jan 28, 2017 2:57 am

Optimizing new Chromecast preset to increase quality

Post by Hbortin » Sat Jan 28, 2017 3:08 am

Hi,

I have some older DVDs and videos that I burned in MKV and AVI formats and I'm now trying to convert everything to be Chromecast Compatible. Although I'm still able to stream most of those videos on my Synology via PLEX to Chromecast, the Synology CPU usage gets pretty high and I just want to eliminate any transcoding.

It's great that there is now a preset called "Chromecast 1080p30 Surround", but I'm thinking the quality is set to average on it rather than have something like Fast Chromecast, HQ Chromecast, and Super HQ Chromecast. I was wondering if anyone has some tips or details of what settings I can modify on the default Chromecast preset to maximize the quality of the video without having to transcode for Chromecast. Storage space is not an issue as neither is the network bandwidth, I just don't want to lose much quality on important videos.

Thanks for any tips and suggestions!

Hbortin
Posts: 5
Joined: Sat Jan 28, 2017 2:57 am

Re: Optimizing new Chromecast preset to increase quality

Post by Hbortin » Wed Feb 01, 2017 7:50 am

After playing around with it quite some time, I have two questions that I cant figure out...

1) What does the default chromecast present that create a second audio track with AC3 Passthrough do? When I select this second audio layer to play from NAS to Chromecast, I see it starts to transcode it. So I'm trying to figure out what it's supposed to do if it's not meant to be played on Chromecast. Also, since I don't know what it does I don't remove it. So I actually started adding the same type of passthrough track for each audio track a movie has (https://goo.gl/PKp65i), does that sound like the right thing to do?

2) When adding an audio track, the default Bitrate is set to 160. I played around with this and found that when setting it to "Quality: 1" instead, it produces very similar results. Sometimes its even better because it seems to tune it to the audio track itself. If the original track is bitrate 160, it would probably set it to 180. In one case with a cartoon, the original bitrate was 45, but setting the default chromecast of Bitrate 160 made a disturbing pitch/freeze in one scene of the clip (starting song). But when I set it to Quality 1, it knew to jump up the Bitrate to 180 and it sounded perfect. So would you say the not defaulting to Bitrate 160 and using the Bitrate 1 is a slightly better approach sometime since it seems a bit "smart" in knowing how to set bitrate per clip?

rollin_eng
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Re: Optimizing new Chromecast preset to increase quality

Post by rollin_eng » Wed Feb 01, 2017 7:58 am

Could you please post your logs, instructions can be found here:

viewtopic.php?f=6&t=31236

Hbortin
Posts: 5
Joined: Sat Jan 28, 2017 2:57 am

Re: Optimizing new Chromecast preset to increase quality

Post by Hbortin » Wed Feb 01, 2017 8:48 am

Success using Quality 1: http://pastebin.com/x4gAEzuC (Resulting file: http://ge.tt/3WTGLci2)
Sound issue using Default Bitrate 160: http://pastebin.com/N43MnXtj (Resulting file: http://ge.tt/4xiCLci2)

Note that the sound issue was occurring on every single episode at the same exact spot (Sound when logo appears) when using bitrate 160.


Also, if you can help explain the need for the passthrough audio in default Chromecast setting and if it needs to be added to each new audio track.

Thanks!

mduell
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Re: Optimizing new Chromecast preset to increase quality

Post by mduell » Wed Feb 01, 2017 5:18 pm

Move the video quality slider toward higher quality for higher quality. Only move it a couple points at a time, very low values aren't very useful.

Hbortin
Posts: 5
Joined: Sat Jan 28, 2017 2:57 am

Re: Optimizing new Chromecast preset to increase quality

Post by Hbortin » Wed Feb 01, 2017 7:03 pm

Hi, thanks for the quality slider tip. I did play around with that already and saw very little improvement, just HUGE file size increases.

Mostly I'm just curious now 1) if setting the sound to "Quality:1" will always yield better results(despite sometimes slightly larger file size) than setting it to "Bitrate: 160"? 2) Do I need/should always create a AC3 Passthrough track for each additional audio track I add to a clip.

BTW, I also took off the foreign audio scan because I realized it doesn't actually add any subtitles, just translates the existing text on the screen into some language.

Hbortin
Posts: 5
Joined: Sat Jan 28, 2017 2:57 am

Re: Optimizing new Chromecast preset to increase quality

Post by Hbortin » Fri Feb 03, 2017 3:42 pm

Based on additional testing, I decided to just go with Sound quality:1 since it seems to provide same or better results. Also, added the passthrough audio for each new audio track added so that it's consistent with the default presets.

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