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Force audio transcode - Printable Version

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Force audio transcode - Savage1 - 2025-02-12

Multichannel AAC seems pretty useless to me, is there anyway to make jellyfin convert it to something useful like AC3? 

My server is running the latest version, clients are windows boxes running jellyfin media player linked to Denon receivers. At the moment jellyfin turns the multichannel AAC into stereo. DTS, DD+ etc all play fine I just need to find a way to force audio transcoding for AAC.

RE: Force audio transcode - theguymadmax - 2025-02-12

Click on the Profile Avatar at the top right of the JMP home screen, then select "Playback." In the "Video Advance" section, choose "Preferred transcode audio codec in video playback." From there, you can select your preferred audio codec.

RE: Force audio transcode - gnattu - 2025-02-12

(Yesterday, 08:18 PM)theguymadmax Wrote: Click on the Profile Avatar at the top right of the JMP home screen, then select "Playback." In the "Video Advance" section, choose "Preferred transcode audio codec in video playback." From there, you can select your preferred audio codec.

That won't work for JMP because JMP has its own profile builder and that is not what the OP wants anyway. His sound system does not work with multichannel aac and he wants to blacklist multichannel aac to be supported at all which is currently impossible.

RE: Force audio transcode - theguymadmax - 2025-02-12

Worked when i tried it.

Before (on Auto):
Code:
  Stream #0:0(eng): Video: h264 (High), yuv420p(progressive), 1920x800 [SAR 1:1 DAR 12:5], 23.98 fps, 23.98 tbr, 1k tbn (default)
  Stream #0:1(eng): Audio: ac3, 48000 Hz, 5.1(side), fltp, 640 kb/s (default)
  Stream #0:2(eng): Subtitle: subrip (srt)
      Metadata:
        title          : English regular
  Stream #0:3(eng): Subtitle: subrip (srt)
      Metadata:
        title          : English sdh
Stream mapping:
  Stream #0:0 -> #0:0 (h264 (native) -> h264 (h264_qsv))
  Stream #0:1 -> #0:1 (ac3 (native) -> aac (libfdk_aac))
Press [q] to stop, [?] for help
Output #0, hls, to '/cache/transcodes/302859ceecd538c0250b1ab989142974.m3u8':
  Metadata:
    encoder        : Lavf61.1.100
  Stream #0:0: Video: h264, qsv(bt709, progressive), 1920x800 [SAR 1:1 DAR 12:5], q=2-31, 2552 kb/s, 23.98 fps, 90k tbn (default)
      Metadata:
        encoder        : Lavc61.3.100 h264_qsv
      Side data:
        cpb: bitrate max/min/avg: 2552000/0/2552000 buffer size: 5104000 vbv_delay: N/A
  Stream #0:1: Audio: aac, 48000 Hz, 5.1, s16, 448 kb/s (default)
      Metadata:
        encoder        : Lavc61.3.100 libfdk_aac
[hls @ 0x62a513a85040] Opening '/cache/transcodes/302859ceecd538c0250b1ab9891429740.ts' for writing
frame=  88 fps=0.0 q=20.0 size=N/A time=00:00:00.00 bitrate=N/A speed=  0x 

After setting it to AC3:
 
Code:
Stream #0:0(eng): Video: h264 (High), yuv420p(progressive), 1920x800 [SAR 1:1 DAR 12:5], 23.98 fps, 23.98 tbr, 1k tbn (default)
  Stream #0:1(eng): Audio: ac3, 48000 Hz, 5.1(side), fltp, 640 kb/s (default)
  Stream #0:2(eng): Subtitle: subrip (srt)
      Metadata:
        title          : English regular
  Stream #0:3(eng): Subtitle: subrip (srt)
      Metadata:
        title          : English sdh
Stream mapping:
  Stream #0:0 -> #0:0 (h264 (native) -> h264 (h264_qsv))
  Stream #0:1 -> #0:1 (ac3 (native) -> ac3 (native))
Press [q] to stop, [?] for help
Output #0, hls, to '/cache/transcodes/5c7eaf63c3a38adfa6de10bdb483d653.m3u8':
  Metadata:
    encoder        : Lavf61.1.100
  Stream #0:0: Video: h264, qsv(bt709, progressive), 1920x800 [SAR 1:1 DAR 12:5], q=2-31, 2552 kb/s, 23.98 fps, 90k tbn (default)
      Metadata:
        encoder        : Lavc61.3.100 h264_qsv
      Side data:
        cpb: bitrate max/min/avg: 2552000/0/2552000 buffer size: 5104000 vbv_delay: N/A
  Stream #0:1: Audio: ac3, 48000 Hz, 5.1(side), fltp, 448 kb/s (default)
      Metadata:
        encoder        : Lavc61.3.100 ac3
[hls @ 0x5d6346b12040] Opening '/cache/transcodes/5c7eaf63c3a38adfa6de10bdb483d6530.ts' for writing
frame=  140 fps=0.0 q=21.0 size=N/A time=00:00:00.00 bitrate=N/A speed=  0x   
[hls @ 0x5d6346b12040] Opening '/cache/transcodes/5c7eaf63c3a38adfa6de10bdb483d6531.ts' for writing
[hls @ 0x5d6346b12040] Opening '/cache/transcodes/5c7eaf63c3a38adfa6de10bdb483d6532.ts' for writing
frame=  283 fps=283 q=29.0 size=N/A time=00:00:05.96 bitrate=N/A speed=5.96x

Also, like gnattu mentioned JMP has it's own audio settings.  Go to settings then client settings, from there you can try to pass-through AC3, if your outputting via HDMI. (that shouldn't make a difference if your source is AAC, but wanted you to know about the options in that menu)

   

RE: Force audio transcode - gnattu - 2025-02-12

Why is it transcoding in the first place? JMP won't transcode unless you forced transcode everything doesn't it?

RE: Force audio transcode - theguymadmax - 2025-02-12

I lowered the bit rate to 3Mpbs. I guess that's key, change audio to AC3 in webui, then force transcode by lowering the bitrate.

RE: Force audio transcode - gnattu - 2025-02-12

(Yesterday, 08:48 PM)theguymadmax Wrote: I lowered the bit rate to 3Mpbs.

And that is not really a solution. That is useless because you cannot force OP to have crappy video quality for everything just to transcode to AC3. JMP does have a "force transcode everything" option to not compress the bitrate but that is still, far from ideal.

RE: Force audio transcode - theguymadmax - 2025-02-12

Yep, I agree. I wouldn't sacrifice video quality for audio quality.

For media that's only in AAC, I've converted it to AC3 and muxed it back into the container. I think that might be your best option. With Jellyfin, you can also use it as an external audio track if needed.

RE: Force audio transcode - Savage1 - 2025-02-12

(Yesterday, 08:18 PM)theguymadmax Wrote: Click on the Profile Avatar at the top right of the JMP home screen, then select "Playback." In the "Video Advance" section, choose "Preferred transcode audio codec in video playback." From there, you can select your preferred audio codec.

I tried this but no difference, still just converts to stereo. I'm going to try a newer firmware in my receivers just incase they will take multichannel pcm but they are old.

RE: Force audio transcode - Savage1 - 2025-02-12

(Yesterday, 08:26 PM)gnattu Wrote: That won't work for JMP because JMP has its own profile builder and that is not what the OP wants anyway. His sound system does not work with multichannel aac and he wants to blacklist multichannel aac to be supported at all which is currently impossible.

Yes blacklist is a good term basically if a file is multichannel AAC id like AC3 or something else my receivers can understand if a file is not multichannel AAC I just want it to play as normal without the excess workload caused by transcoding.
 However if that's impossible I guess I need to learn how tdarr works and get rid of all the AAC files.