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Chromecast AC3 passthrough when transcoding video/container


plastrd

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Server version 3.0.5713.6 beta

 

I've been experimenting with the live TV support and recorded last night's re-run of The Simpsons from my HDHR Prime (mediainfo below). When casting this recording to my Chromecast, it transcodes the video to h264 as it should, but it is also transcoding the audio to AAC despite the Chromecast AC3 Passthrough option being checked. The log shows ffmpeg being told to transcode both audio and video.

 

Meanwhile an episode of Backstrom that I have encoded in h264/AC3 is direct streaming to the Chromecast without any interference at all (and with AC3 being received by my receiver). This is great!

 

Is the server supposed to go "whole hog" when transcoding when only one or two issues are present that would prevent direct streaming (in this case video codec and container)? What I'm wondering is if the server could have ffmpeg transcode the video and just copy the existing AC3 audio to the output instead of transcoding to AAC?

 

Unrelated issue, I couldn't switch the audio stream to the spanish one to see what would happen but I'm less concerned about that right now.

 

Media Info for The Simpsons .ts recording:
Video
Codec MPEG2VIDEO
Profile Main
Level 4
Resolution 1280x720
Aspect ratio 16:9
Anamorphic No
Interlaced No
Framerate 59.94006
Bitrate 12234 kbps
Bit depth 8 bit
Pixel format yuv420p
Audio
Language eng
Codec AC3
Layout 5.1
Channels 6 ch
Bitrate 437 kbps
Sample rate 48000 khz
Default No
Audio
Language spa
Codec AC3
Layout stereo
Channels 2 ch
Bitrate 187 kbps
Sample rate 48000 khz
Default No
Container ts
Path D:\DVR\Series\The Simpsons\The Simpsons S26E21 Bull-E.ts
 
Media Info for Backstrom .mkv direct stream
Video
Codec H264
Profile High
Level 41
Resolution 1280x720
Aspect ratio 16:9
Anamorphic No
Interlaced No
Framerate 23.97602
Bitrate 3505 kbps
Bit depth 8 bit
Pixel format yuv420p
Ref frames 5
CABAC Yes
Audio
Codec AC3
Layout 5.1
Channels 6 ch
Bitrate 375 kbps
Sample rate 48000 khz
Default Yes
Container mkv
Path D:\TV\Backstrom\Backstrom.S01E01.720p.HDTV.mkv
 
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