Is it possible to customise video and audio transcoding settings?

[Charlie117 56]

Hi all,

I'm wondering if it's possible to customise the settings used for transcoding, both video and audio.

I've noticed a couple transcoding settings available in the server dashboard, but those are a bit too limited for me.

 

Basically, I would like to be able to specify custom x264 settings the transcoder should use and also specify the bitrate it should use for transcoding audio to Dolby Digital (AC-3) 5.1.

 

For example, I'm currently using the 'slower' preset for x264 but according to the transcoder log it is still using some very mediocre settings for transcoding:

 

264 - core 152 r2854 e9a5903 - H.264/MPEG-4 AVC codec - Copyleft 2003-2017 - http://www.videolan.org/x264.html - options: cabac=1 ref=4 deblock=1:0:0 analyse=0x1:0 me=dia subme=0 psy=1 psy_rd=1.00:0.00 mixed_ref=1 me_range=4 chroma_me=0 trellis=2 8x8dct=0 cqm=0 deadzone=21,11 fast_pskip=1 chroma_qp_offset=0 threads=12 lookahead_threads=4 sliced_threads=0 nr=0 decimate=1 interlaced=0 bluray_compat=0 constrained_intra=0 bframes=3 b_pyramid=2 b_adapt=2 b_bias=0 direct=1 weightb=1 open_gop=0 weightp=2 keyint=250 keyint_min=23 scenecut=40 intra_refresh=0 rc_lookahead=10 rc=crf mbtree=1 crf=18.0 qcomp=0.60 qpmin=0 qpmax=69 qpstep=4 vbv_maxrate=29616 vbv_bufsize=59232 crf_max=0.0 nal_hrd=none filler=0 ip_ratio=1.40 aq=1:1.00

I would love to tweak this to my liking, improving picture quality at a cost of a higher CPU load.

 

Also for audio, I would like to raise the default bitrate of 384 kb/s to the maximum of 640 kb/s.

 

 

Stream #0:1 -> #0:1 (dts (dca) -> ac3 (native))

Stream #0:1(eng): Audio: ac3, 48000 Hz, 5.1, fltp (16 bit), 384 kb/s (default)

 

Any help would be much appreciated!

Edited December 23, 2018 by Charlie117

[Luke 37119]

Hi there, is no audio bitrate setting as of now.

 

What other video settings would you like to customize?

[Charlie117 56]

Hi there, is no audio bitrate setting as of now.

 

What other video settings would you like to customize?

 

Hi Luke,

 

Many thanks for the information.

 

I think it would be useful if there was an option to specify the audio bitrate for AC-3 transcoding. Nowadays streaming platforms such as Amazon Prime and Netflix are using AC-3+ at 640 Kbps and I think users should at least have the option to set it higher based on their own requirements. I certainly agree though that AC-3 at 384 Kbps is a decent default value for most people.

 

Now for video it's a bit more complicated, but ideally it would be great if people could dial in every setting x264 allows. My short list of settings (and their preferred setting for myself) are written below. Of course, with 1 set of x264 settings you need to make a compromise between optimising for clean live action, grain live action and animation. Considering I don't watch a lot of animation, I prefer to optimise my x264 settings for the first two.

 

deblock=1:0:0 -> deblock=1:-3:-3

analyse=0x1:0 -> analyse=0x3:0x113

me=dia -> me=hex

me_range=4 -> me_range=16

bframes=3 ->  bframes=5

mbtree=1 mbtree=0

aq=1:1.00 -> aq=3:0.80

 

These are just some of things I'd like to change. Some may be too much for realtime encoding depending on the Emby server CPU.

[Luke 37119]

Yes these are possible for the future. Thanks.

[Charlie117 56]

Yes these are possible for the future. Thanks.

 

Thanks Luke. Should I make feature requests for both things in the correct forum?

[Luke 37119]

The feature request forum is the best place. Thanks.