Chromecast and AC3 passthrought

[CBers 6771]

@@Latchmor - I saw your posts with Luke last night.

 

I tried the same version but my MKVs still transcoded, converting AC3 to AAC.

[eraser8 46]

Hi guys,

 

Is there a way for me to manually modify my chromecast profile on my MB Server?

 

Thanks

[KRA 39]

Also there should be no need to do a full transcode if it's a mkv, just change the container to mp4 and directcopy the video and audio stream.

[CBers 6771]

Also there should be no need to do a full transcode if it's a mkv, just change the container to mp4 and directcopy the video and audio stream.

Do you mean convert, or just change the extension?

[KRA 39]

ffmpeg -i input.mkv -vcodec copy -acodec copy out.mp4

 

This is done within seconds and you have a file chromecast can read, if the video and audio content is a format chromecast reads.

[eraser8 46]

Pretty good solution to be able to play our .mkv through the Chromecast. I like it and it should not be a big process load.

[KRA 39]

everything i've read points to ref=4 as the max. what can i refer to that indicates 5?

 

http://en.wikipedia.org/wiki/H.264/MPEG-4_AVC#Levels

 

1,280×720@68.3 (9 ref)

1,920×1,080@30.1 (4 ref)

2,048×1,024@30.0 (4 ref)

 

Note that on cropped media, such as 1920x800 high@L4.1 - CC should handle 5 ref just fine because it's within the buffer limits of the specs.

[OddbOd 21]

Spot on KRA and the math proves it:-

 

maximum ref = MaxDPB * 1024 / ( FrameWidth * FrameHeight * 1.5)

                      = 12288 * 1024 / (1920 * 800 * 1.5)

                        = 5 (rounded down to the nearest integer)

 

Maybe the Chromecast takes a naive approach to decide whether or not to play a video. Something along the lines of, if the height is greater than 720 and the number of references is greater than 4 don't even attempt playback.

 

everything i've read points to ref=4 as the max. what can i refer to that indicates 5?

 

https://en.wikibooks.org/wiki/MeGUI/x264_Settings#ref

[Luke 37071]

@@OddbOd, we actually don't restrict on refframes anymore for chromecast. What we now is try to play, and if it fails we automatically switch to transcoding.

[OddbOd 21]

@@Luke, that is hilarious, I suggested exactly the same technique be implemented in the unofficial Samsung client (last paragraph of https://emby.media/community/index.php?/topic/31627-framerate-check-causes-playback-failure-or-unwanted-transcoding/?p=304099)and was ignored.

[Luke 37071]

@@Luke, that is hilarious, I suggested exactly the same technique be implemented in the unofficial Samsung client (last paragraph of https://emby.media/community/index.php?/topic/31627-framerate-check-causes-playback-failure-or-unwanted-transcoding/?p=304099)and was ignored.

 

We have it in our official Samsung app as well.