Emby Media Server - HW accelerated transcoding

[memeka]

With the ffmpeg patches that enable encoding, and with a few modifications to emby media server, I was able to do hardware transcoding when streaming from emby server.

emby.jpg

(117.54 KiB) Downloaded 286 times

Not sure if there are any emby users (most people i guess want plex), but since plex uses its own ffmpeg (and code is not open), it's a bit harder to have hw transcoding than with emby.

Here's the server log:

Code: Select all

http://129.127.248.18:8096/emby/videos/0263a73ae384c2feef7b07256f1a8c97/hls1/main/0.ts?DeviceId=39bd3c935755c4f8f5fb742f0026f67ae17b13f9&MediaSourceId=0263a73ae384c2feef7b07256f1a8c97&VideoCodec=h264&AudioCodec=aac,mp3&AudioStreamIndex=1&VideoBitrate=599872296&AudioBitrate=127704&Level=51&Profile=high&PlaySessionId=e47b6e3376b94bae846e45d4909a843e&api_key=eebfa201aa2b453ea72febf6b65943d1&CopyTimestamps=false&TranscodingMaxAudioChannels=6&EnableSubtitlesInManifest=false&Tag=014fae5077a8f8d2ee962659fef2a772&RequireAvc=true

{"Protocol":"File","Id":"0263a73ae384c2feef7b07256f1a8c97","Path":"/home/odroid/Video/mono.avi","Type":"Default","Container":"avi","Name":"SD/MSMPEG4/MP3","IsRemote":false,"ETag":"014fae5077a8f8d2ee962659fef2a772","RunTimeTicks":80035233792,"ReadAtNativeFramerate":false,"SupportsTranscoding":true,"SupportsDirectStream":true,"SupportsDirectPlay":true,"IsInfiniteStream":false,"RequiresOpening":false,"RequiresClosing":false,"SupportsProbing":true,"VideoType":"VideoFile","MediaStreams":[{"Codec":"msmpeg4","CodecTag":"DIV3","TimeBase":"4171/100000","CodecTimeBase":"4171/100000","IsInterlaced":false,"BitRate":573722,"RefFrames":1,"IsDefault":false,"IsForced":false,"Height":288,"Width":512,"AverageFrameRate":23.97507,"RealFrameRate":23.97507,"Type":"Video","AspectRatio":"16:9","Index":0,"IsExternal":false,"IsTextSubtitleStream":false,"SupportsExternalStream":false,"PixelFormat":"yuv420p","Level":-99,"IsAnamorphic":false},{"Codec":"mp3","TimeBase":"1/15963","CodecTimeBase":"1/44100","DisplayTitle":"MP3 stereo","IsInterlaced":false,"ChannelLayout":"stereo","BitRate":127704,"Channels":2,"SampleRate":44100,"IsDefault":false,"IsForced":false,"Type":"Audio","Index":1,"IsExternal":false,"IsTextSubtitleStream":false,"SupportsExternalStream":false,"Level":0,"IsAnamorphic":false}],"PlayableStreamFileNames":[],"Formats":[],"Bitrate":706525,"RequiredHttpHeaders":{}}

/usr/local/bin/ffmpeg -f avi -codec:0 msmpeg4 -codec:1 mp3 -i file:"/home/odroid/Video/mono.avi" -map_metadata -1 -map_chapters -1 -threads 0 -map 0:0 -map 0:1 -map -0:s -codec:v:0 h264_v4l2m2m -pix_fmt nv21  -b:v 573722 -maxrate 573722 -bufsize 1147444 -vsync -1 -force_key_frames "expr:gte(t,n_forced*3)" -vf "scale=trunc(min(max(iw\,ih*dar)\,720)/2)*2:trunc(ow/dar/2)*2" -copyts -codec:a:0 copy -f segment -max_delay 5000000 -avoid_negative_ts disabled -start_at_zero -segment_time 3  -individual_header_trailer 0 -segment_format mpegts -segment_list_type m3u8 -segment_start_number 0 -segment_list "/home/odroid/src/emby/Emby-3.2.8/Tools/Linux_Build_Scripts/mediabrowser/MediaBrowser.Mono.3.2.8.0/ProgramData-Server/transcoding-temp/117f397dcd8a9192fa06100a7d26448f.m3u8" -y "/home/odroid/src/emby/Emby-3.2.8/Tools/Linux_Build_Scripts/mediabrowser/MediaBrowser.Mono.3.2.8.0/ProgramData-Server/transcoding-temp/117f397dcd8a9192fa06100a7d26448f%d.ts"


ffmpeg version 3.0.2 Copyright (c) 2000-2016 the FFmpeg developers
  built with gcc 6.3.0 (Debian 6.3.0-6) 20170205
  configuration: --prefix=/usr/local --libdir=/usr/local/lib --incdir=/usr/local/include --pkg-config-flags=--static --enable-gpl --enable-static --enable-avresample --enable-avisynth --enable-gnutls --enable-ladspa --enable-libass --enable-libbluray --enable-libbs2b --enable-libcaca --enable-libcdio --enable-libflite --enable-libfontconfig --enable-libfreetype --enable-libfribidi --enable-libgme --enable-libgsm --enable-libmodplug --enable-libmp3lame --enable-libopus --enable-libpulse --enable-librubberband --enable-librtmp --enable-libshine --enable-libsnappy --enable-libsoxr --enable-libspeex --enable-libssh --enable-libtheora --enable-libtwolame --enable-libvorbis --enable-libvpx --enable-libwavpack --enable-libwebp --enable-libx265 --enable-libxvid --enable-libzvbi --enable-openal --enable-opengl --disable-stripping
  libavutil      55. 17.103 / 55. 17.103
  libavcodec     57. 24.102 / 57. 24.102
  libavformat    57. 25.100 / 57. 25.100
  libavdevice    57.  0.101 / 57.  0.101
  libavfilter     6. 31.100 /  6. 31.100
  libavresample   3.  0.  0 /  3.  0.  0
  libswscale      4.  0.100 /  4.  0.100
  libswresample   2.  0.101 /  2.  0.101
  libpostproc    54.  0.100 / 54.  0.100
Input #0, avi, from 'file:/home/odroid/Video/mono.avi':
  Duration: 02:13:23.52, start: 0.000000, bitrate: 706 kb/s
    Stream #0:0: Video: msmpeg4v3 (DIV3 / 0x33564944), yuv420p, 512x288, 573 kb/s, 23.98 fps, 23.98 tbr, 23.98 tbn, 23.98 tbc
    Stream #0:1: Audio: mp3 (U[0][0][0] / 0x0055), 44100 Hz, stereo, s16p, 127 kb/s
[h264_v4l2m2m @ 0x80886330] Device path not set, probing /dev/video*
[h264_v4l2m2m @ 0x80886330] Using device /dev/video11
[h264_v4l2m2m @ 0x80886330] mfc-enc: gop_size: 12
[h264_v4l2m2m @ 0x80886330] mfc-enc: enabling bitrate control if required rate 573722 > 1
[h264_v4l2m2m @ 0x80886330] mfc-enc: max b-frames: 0
[h264_v4l2m2m @ 0x80886330] mfc-enc: h264 profile: 4
[h264_v4l2m2m @ 0x80886330] mfc-enc: min/max quantizer scale: (2, 31)
[h264_v4l2m2m @ 0x80886330] mfc-enc: h264 level: V4L2_MPEG_VIDEO_H264_LEVEL_4_0
Output #0, segment, to '/home/odroid/src/emby/Emby-3.2.8/Tools/Linux_Build_Scripts/mediabrowser/MediaBrowser.Mono.3.2.8.0/ProgramData-Server/transcoding-temp/117f397dcd8a9192fa06100a7d26448f%d.ts':
  Metadata:
    encoder         : Lavf57.25.100
    Stream #0:0: Video: h264 (h264_v4l2m2m), nv21, 512x288, q=2-31, 573 kb/s, 23.98 fps, 90k tbn, 23.98 tbc
    Metadata:
      encoder         : Lavc57.24.102 h264_v4l2m2m
    Stream #0:1: Audio: mp3 (U[0][0][0] / 0x0055), 44100 Hz, stereo, 127 kb/s
Stream mapping:
  Stream #0:0 -> #0:0 (msmpeg4v3 (msmpeg4) -> h264 (h264_v4l2m2m))
  Stream #0:1 -> #0:1 (copy)
Press [q] to stop, [?] for help
[h264_v4l2m2m @ 0x80886330] Performing useless memcpy() on output pool because buffers do not match
[h264_v4l2m2m @ 0x80886330] This could be avoided by using av_v4l_buffer_pool_get_buffer*() or av_v4l_buffer_pool_make_pipe()
[segment @ 0x80887200] Timestamps are unset in a packet for stream 0. This is deprecated and will stop working in the future. Fix your code to set the timestamps properly
[segment @ 0x80887200] Encoder did not produce proper pts, making some up.
frame=  439 fps=0.0 q=-0.0 size=N/A time=00:00:19.03 bitrate=N/A speed=  38x    
frame=  857 fps=856 q=-0.0 size=N/A time=00:00:36.53 bitrate=N/A speed=36.5x    
frame= 1259 fps=838 q=-0.0 size=N/A time=00:00:53.04 bitrate=N/A speed=35.3x    
frame= 1667 fps=833 q=-0.0 size=N/A time=00:01:10.02 bitrate=N/A speed=  35x  

[memeka]

Requirements:

* kernel patch to enable encoder timestamps: https://github.com/mihailescu2m/linux/c ... cc26aabc09
* patched ffmpeg: https://github.com/mihailescu2m/FFmpeg/ (the v4l2_m2m branches)
* emby patch: http://paste.debian.net/922751/

[memeka]

I tried transcoding 4K HEVC and streaming to a browser in 720p using emby + mfc:

frame= 2002 fps= 12 q=-0.0 size=N/A time=00:01:24.08 bitrate=N/A speed=0.519x

seems like i wanted too much the video would "buffer" every minute or so (the problem being that transcoding speed with 4K HEVC software decoding was 52% framerate)

[kicker22004]

I'm interested in trying this out, I've managed to get encoding to work for Plex but with the normal issues. Any chance you could post your steps for setting this up? Thank you

[memeka]

i'll be releasing an update to my wayland-stretch image that will contain emby server

[bgx]

Great! I just ordered a odroid xu4 and wait paitently for your emby server ffmpeg package.

[rooted]

Could you post a video of the quality?

[memeka]

Could you post a video of the quality?

quality is good but cannot show since i only got old 480p avi movies to transcode all my HD media is h264
but transcoding manually with ffmpeg with the same settings show good quality (higher quality with higher bitrate)...

[rooted]

So no strange artifacts and quality matched bitrate, good enough for me.

[bgx]

Yesterday I got my XU4. Hope that memeka will release his tuned emby version when he's back from vacation.

[johnvick]

I am running dietpi v150, kernel 4.9 and Emby - I was hoping the new kernel would help with video transcoding but 1080p still stutters. I don't know if this is overheating as the device went up to 95 C.

I then tried using the custom ffmpeg as in this post:

viewtopic.php?f=95&t=24366

but I got errors and it didn't install.

I see Emby has an option to select between system ffmpeg and custom one. Anyone help to get this working?

John

[memeka]

I am running dietpi v150, kernel 4.9 and Emby - I was hoping the new kernel would help with video transcoding but 1080p still stutters. I don't know if this is overheating as the device went up to 95 C.

I then tried using the custom ffmpeg as in this post:

viewtopic.php?f=95&t=24366

but I got errors and it didn't install.

I see Emby has an option to select between system ffmpeg and custom one. Anyone help to get this working?

John

download emby 3.2.8 from:

Code: Select all

https://oph.mdrjr.net/memeka/emby/

it's got support for Exynos MFC (XU4) hardware transcoding - you need to select it from the emby transcoding settings.
you will also need to install the ffmpeg (3.2) packages from that folder. they are for debian stretch, so i don't know if other package requirements will be satisfied on your distribution.
@meveric has ffmpeg packages for debian jessie at https://oph.mdrjr.net/meveric/kernel/XU3/4.9.x/ffmpeg/ , so you may try those, they are more compatible with older distributions.

[johnvick]

Thanks this looks promising but is this version of Emby for Windows?

[memeka]

Thanks this looks promising but is this version of Emby for Windows?

why would it be for Windows? it runs on the XU4

emby is a .NET application, so you need to install mono dependencies. check the linux install guide from their website for more details.

[johnvick]

Just saw all the dll files and thought WIndows

I have Emby and Mono installed already through the diet pi menus system. I'm not sure how to install the version you have?

Thanks, John

[memeka]

extract the archive and overwrite the one you have installed

[johnvick]

extract the archive and overwrite the one you have installed

Thanks for your help with this - where is emby installed?

I have a lot of stuff in /var/lib/emby-server but this doesn't look like the right place.

And doesn't your custom version get overwritten with the next emby update?

[memeka]

don't update emby
also, i have no idea where emby gets installed by dietpi you'll have to ask whoever packaged it...

[bgx]

download emby 3.2.8 from:

Code: Select all

https://oph.mdrjr.net/memeka/emby/

it's got support for Exynos MFC (XU4) hardware transcoding - you need to select it from the emby transcoding settings.
you will also need to install the ffmpeg (3.2) packages from that folder. they are for debian stretch, so i don't know if other package requirements will be satisfied on your distribution.
@meveric has ffmpeg packages for debian jessie at https://oph.mdrjr.net/meveric/kernel/XU3/4.9.x/ffmpeg/ , so you may try those, they are more compatible with older distributions.

Oh, great to hear memeka. That's the same what I want to do. I will try later when I'm at home. Thx

EDIT: Is there a way to patch a newer version by myself to got support for MFC?

[johnvick]

don't update emby
also, i have no idea where emby gets installed by dietpi you'll have to ask whoever packaged it...

The DietPi version of Emby comes from the opensuse repository but beyond that I don't know much.

Also tried the Jessie ffmpeg https://oph.mdrjr.net/meveric/kernel/XU3/4.9.x/ffmpeg/

But it didn't install under DietPi - several error messages. Completely broke ffmpeg so I had to restore from backup.

John

[bgx]

don't update emby
also, i have no idea where emby gets installed by dietpi you'll have to ask whoever packaged it...

The DietPi version of Emby comes from the opensuse repository but beyond that I don't know much.

Also tried the Jessie ffmpeg https://oph.mdrjr.net/meveric/kernel/XU3/4.9.x/ffmpeg/

But it didn't install under DietPi - several error messages. Completely broke ffmpeg so I had to restore from backup.

John

Same problem here

[memeka]

sorry i don't know what packages DietPi uses

[Padroid]

Hey, I was just looking to try this myself on my XU4 running Ubuntu 16.04.2 minimal, and but I couldn't even get emby-server to install using the opensuse repositories. Got a lot of unmet dependencies, some of which can't be installed with the existing repositories. Do I need to add something to the sources list, or is there a way to install this version of emby directly, rather than overwriting some of the files with the aforementioned patch?

[memeka]

you can unzip and run
but you need to have all required mono packages installed.

[Padroid]

Unzip and run MediaBrowser.Server.Mono.exe from MediaBrowser.Mono.3.2.8.0.tar.gz on Ubuntu? How is the exe supposed to run without wine, or is there no way to run it natively?

And where do I get the mono packages? Are they the .deb binaries in the same directory?

[mad_ady]

Mono is an opensource implementation of the dotNET apis, so, as long as the application doesn't make any native windows calls, you won't need wine to run it (even on x86).
Regarding running nativelly, it's the same as running java. It's not cpu emulation, but it's interpreting some bytecode.

[Padroid]

Huh, so it's interpreting at runtime like Java? Wouldn't that increase the overhead compared to something compiled ahead of time?
Also, I found the repository to get mono here: http://www.mono-project.com/download/#d ... lin-ubuntu, but it still seems like I don't have the needed repositorie(s) for libembysqlite3-0 and embymagick. Thanks for jumping in. Am I understanding correctly, that if I can get these packages and install emby-server, I need only overwrite files that will be installed in the process with those having the same names from the tarball in https://oph.mdrjr.net/memeka/emby/ and install the ffmpeg packages from the same directory? Or am I supposed to somehow use mono to run/install the files from the tarball directly?

[mad_ady]

I wouldn't know - I don't use emby. I'm sure @memeka can help you

[Padroid]

Ah, well thanks anyway. What do you use? Plex? Is there a way to do HW transcoding with a media server besides the one mentioned here?

[crazyquark]

I wanted to do this for my setup but without a reproducible method to patch future emby versions I held back.
FYI, I just installed Plex and it has an "original" version feature in playback that does no transcoding so you can save your cores some pain. Wish emby had that feature.

This is sad, I really liked emby...
I might keep both around, emby for my Kodi and Plex for all other devices.

[crazyquark]

Requirements:

* kernel patch to enable encoder timestamps: https://github.com/mihailescu2m/linux/c ... cc26aabc09
* patched ffmpeg: https://github.com/mihailescu2m/FFmpeg/ (the v4l2_m2m branches)
* emby patch: http://paste.debian.net/922751/

@memeka: the last link seems to be dead.
Could you repost it?

[Padroid]

@crazyquark If you've had some luck with the ordinary version of emby, do you know what repository I should use for the unmet/uninstallable libembysqlite3-0 and embymagick packages? Also, are you saying emby can't direct play?

[crazyquark]

It can, supposedly direct play but it seems it chooses not to, at least on the videos I tested while Plex correctly does so.
I think these are the sources I used:

deb http://download.opensuse.org/repositori ... ntu_14.04/ /

[crazyquark]

Is this thread dead?

[Padroid]

Oh sorry, @crazyquark. I certainly hope not, but it looks as if memeka hasn't been active on the forums since the beginning of the month, so I don't know when they'll be back.

[Padroid]

Also, I think I used the equivalent 16.04 repository (because that's what I'm running), but perhaps that was a mistake?

[crazyquark]

Humm, could be that they do not provide the same dependencies on that repo.

[crazyquark]

@memeka, any chance you got provide the emby patch again?
The previous link is dead.

[memeka]

exynos patch 1: https://paste.debian.net/983453/

*new* exynos patch 2 (fixes scaling for some resolutions): https://paste.debian.net/983452/

[studioai]

@memeka

Do you have any plan to submit those code to Emby's git repo?

[memeka]

i thought i did sent patch 1 can't remember
not really that big fan of the android tv app so i stopped using it ...

[bgx]

I am running dietpi v150, kernel 4.9 and Emby - I was hoping the new kernel would help with video transcoding but 1080p still stutters. I don't know if this is overheating as the device went up to 95 C.

I then tried using the custom ffmpeg as in this post:

viewtopic.php?f=95&t=24366

but I got errors and it didn't install.

I see Emby has an option to select between system ffmpeg and custom one. Anyone help to get this working?

John

Now after the patches are in the last emby beta I want to try it again to install patched ffmpeg in dietpi but I'm failed again. Took me 4 hours to repair broken apt-get with missing dependencies.

Could somebody help me to install patched ffmpeg on dietpi?

[bgx]

dietpi is running on debian jessie and use this packages:

Code: Select all

deb http://ftp.debian.org/debian/ jessie main contrib non-free
deb http://ftp.debian.org/debian/ jessie-updates main contrib non-free
deb http://security.debian.org jessie/updates main contrib non-free
deb http://ftp.debian.org/debian/ jessie-backports main contrib non-free

Ok, now I tried to compile ffmpeg for myself with the patch but after finished I don't get the exynos encoder?

Here my buildconfig:

Code: Select all

ffmpeg version 3.1.2 Copyright (c) 2000-2016 the FFmpeg developers
  built with gcc 4.9.2 (Debian 4.9.2-10)
  configuration: --prefix=/root/ffmpeg_build --pkg-config-flags=--static --extra-cflags=-I/root/ffmpeg_build/include --extra-ldflags=-L/root/ffmpeg_build/lib --bindir=/root/bin --enable-gpl --enable-libass --enable-libfdk-aac --enable-libfreetype --enable-libmp3lame --enable-libopus --enable-libtheora --enable-libvorbis --enable-libvpx --enable-libx264 --enable-libx265 --enable-nonfree
  libavutil      55. 28.100 / 55. 28.100
  libavcodec     57. 48.101 / 57. 48.101
  libavformat    57. 41.100 / 57. 41.100
  libavdevice    57.  0.101 / 57.  0.101
  libavfilter     6. 47.100 /  6. 47.100
  libswscale      4.  1.100 /  4.  1.100
  libswresample   2.  1.100 /  2.  1.100
  libpostproc    54.  0.100 / 54.  0.100
Hyper fast Audio and Video encoder
usage: ffmpeg [options] [[infile options] -i infile]... {[outfile options] outfile}...

Code: Select all

DEV.LS h264                 H.264 / AVC / MPEG-4 AVC / MPEG-4 part 10 (decoders: h264 h264_vdpau ) (encoders: libx264 libx264rgb h264_vaapi )
 D.VIL. hap                  Vidvox Hap decoder
 DEV.L. hevc                 H.265 / HEVC (High Efficiency Video Coding) (encoders: libx265 )

I get it working under Ubuntu 16.04 but now I had the problem that the output hat green lines and are distorted.
What I'm doing wrong?

[bgx]

With meverics help I get it working. But now I have another problem. The output seems to big. Is there something I missed?

In Emby I get this:

Code: Select all

Stream mapping:
  Stream #0:0 -> #0:0 (h264 (native) -> h264 (h264_v4l2m2m))
  Stream #0:1 -> #0:1 (copy)
Press [q] to stop, [?] for help
[h264_v4l2m2m @ 0x529120] driver 'exynos-gsc' on card 'exynos-gsc gscaler'
    Last message repeated 1 times
[h264_v4l2m2m @ 0x529120] driver 's5p-mfc' on card 's5p-mfc-enc'
[h264_v4l2m2m @ 0x529120] Using device /dev/video11
[h264_v4l2m2m @ 0x529120] driver 's5p-mfc' on card 's5p-mfc-enc'
[h264_v4l2m2m @ 0x529120] h264 profile not found
[h264_v4l2m2m @ 0x529120] Encoder adjusted: qmin (0), qmax (51)

why is h264 missing and no encoder adjustment set?

What can I do to make it work?

[memeka]

why is h264 missing and no encoder adjustment set?
What can I do to make it work?

it's working, don't worry. you can ignore those messages.
you can check CPU usage when doing transcoding...

[bgx]

why is h264 missing and no encoder adjustment set?
What can I do to make it work?

it's working, don't worry. you can ignore those messages.
you can check CPU usage when doing transcoding...

Ok. But the output is bigger than the input and that's the reason why it's unplayable. What can I do to make the stream smaller? I tried to change the CRF setting for transcoding in emby but that didn't help.

Gesendet von meinem MHA-L29 mit Tapatalk

[memeka]

I see. This means probably you are running the mainline ffmpeg version, which doesn't support bitrate for the XU4.
So every file encoded uses maximum bitrate...
You can try installing this ffmpeg version which is patched to enable bitrate: https://oph.mdrjr.net/memeka/ffmpeg/ see if this one works for you ... (not 100% sure if it's compatible with your OS)

[bgx]

Great memeka,

after installing your ffmpeg version over my last it seems nothing changed. Should I install all other debs also?

Output from emby server:

Code: Select all

frame= 1306 fps= 20 q=-0.0 size=N/A time=00:02:07.00 bitrate=N/A speed=1.96x    
frame= 1316 fps= 20 q=-0.0 size=N/A time=00:02:07.32 bitrate=N/A speed=1.95x    
frame= 1327 fps= 20 q=-0.0 size=N/A time=00:02:07.84 bitrate=N/A speed=1.94x    
frame= 1334 fps= 20 q=-0.0 size=N/A time=00:02:08.09 bitrate=N/A speed=1.93x    
frame= 1345 fps= 20 q=-0.0 size=N/A time=00:02:08.73 bitrate=N/A speed=1.93x    
frame= 1356 fps= 20 q=-0.0 size=N/A time=00:02:09.18 bitrate=N/A speed=1.92x    
frame= 1366 fps= 20 q=-0.0 size=N/A time=00:02:09.47 bitrate=N/A speed=1.91x    
[segment @ 0x563e10] Opening '/var/lib/emby-server/transcoding-temp/0185ef5b260a351fc0420480fbb38c60.m3u8.tmp' for writing
[segment @ 0x563e10] Opening '/var/lib/emby-server/transcoding-temp/0185ef5b260a351fc0420480fbb38c6043.ts' for writing
[segment @ 0x563e10] Opening '/var/lib/emby-server/transcoding-temp/0185ef5b260a351fc0420480fbb38c60.m3u8.tmp' for writing
frame= 1372 fps= 20 q=-0.0 Lsize=N/A time=00:02:09.69 bitrate=N/A speed= 1.9x    
video:517961kB audio:4555kB subtitle:0kB other streams:0kB global headers:0kB muxing overhead: unknown

[memeka]

you need to install libavcodec, but libavcodec might need installing other packages from there as well for compatibility.

[mad_ady]

Offtopic, but I wonder - are there major fixes with regard to encoding that were absent in 4.9? Or is it just that mainline ffmpeg has caught up with existing support?