Nisten 15 Posted October 13, 2017 Share Posted October 13, 2017 (edited) This is more of a general question than an issue report Is there any specific factors/thresholds that would cause audio to transcode to mp3? Most of my media is direct mkv copies of physical discs with the original audio tracks in tact - The only changes i've made is setting the CRF factor of the x264 encoder to a lower value and setting de-interlacing to "bop & weave" , for testing Update - Added logs ffmpeg transcode - 10-13-2017 (1252pm).txt ffmpeg transcode - 10-13-2017 (1254pm).txt ffmpeg transcode - 10-13-2017 (1258pm).txt Edited October 13, 2017 by Nisten Link to comment Share on other sites More sharing options...
Jdiesel 1114 Posted October 13, 2017 Share Posted October 13, 2017 If your Roku isn't hooked up to a device that does AC3 or DTS passthrough it will transcode to 2ch mp3. The Roku can passthrough AC3 and DTS but not decode it. How is your Roku hooked up in your system? Link to comment Share on other sites More sharing options...
Nisten 15 Posted October 13, 2017 Author Share Posted October 13, 2017 roku is hooked up to TV via HDMI 2.1 soundbar is connected to the TV via optical Before i made the CRF and de-interlacing changes, transcoded audio was always ac3 Link to comment Share on other sites More sharing options...
Jdiesel 1114 Posted October 13, 2017 Share Posted October 13, 2017 Can you post a ffmpeg log? Link to comment Share on other sites More sharing options...
Nisten 15 Posted October 13, 2017 Author Share Posted October 13, 2017 Added logs to 1st post, i'm not at home so these are remote streaming ffmpeg logs Link to comment Share on other sites More sharing options...
Jdiesel 1114 Posted October 13, 2017 Share Posted October 13, 2017 Looks like your Roku is only reporting a maximum of two channels "TranscodingMaxAudioChannels=2" Did your Roku audio settings happen to change? Link to comment Share on other sites More sharing options...
Nisten 15 Posted October 13, 2017 Author Share Posted October 13, 2017 Nah, its been set to PCM for about a month now - it used to transcode ac3 but my setup would only decode stereo Attached a couple of logs from 2 and half days ago (before making any crf or de-interlacing) changes ffmpeg transcode - 10-10-2017 (637pm).txt ffmpeg transcode - 10-10-2017 (637pm-2).txt Link to comment Share on other sites More sharing options...
Luke 37064 Posted October 13, 2017 Share Posted October 13, 2017 I would still check your Roku system sound settings. Link to comment Share on other sites More sharing options...
Nisten 15 Posted October 13, 2017 Author Share Posted October 13, 2017 The initial ffmpeg logs are using the Emby Web app via Chrome (external/remote stream) - I'll double check the roku settings when I get home The logs in post #7 are using the Emby Roku app (internal/in-network stream) [before the CRF & de-interlacing changes] Link to comment Share on other sites More sharing options...
Happy2Play 8281 Posted October 13, 2017 Share Posted October 13, 2017 Which app are we referring to? Since Blue Neon has a option to change this behavior. Link to comment Share on other sites More sharing options...
Nisten 15 Posted October 13, 2017 Author Share Posted October 13, 2017 Regular App Link to comment Share on other sites More sharing options...
Nisten 15 Posted October 13, 2017 Author Share Posted October 13, 2017 (edited) Roku is still set to PCM Stereo, has been for a month - this issue just started yesterday though ffmpeg logs of In-network roku streaming attached ffmpeg 10-13-17 625pm.txt ffmpeg 10-13-17 627pm.txt Edited October 13, 2017 by Nisten Link to comment Share on other sites More sharing options...
Happy2Play 8281 Posted October 14, 2017 Share Posted October 14, 2017 I don't think it is related at all but you have a issue with quick sync also [h264_qsv @ 0000000002218320] No device available for decoder (device type qsv for codec h264_qsv). Stream mapping: Stream #0:0 -> #0:0 (h264 (h264_qsv) -> h264 (h264_qsv)) Stream #0:1 -> #0:1 (dts (dca) -> mp3 (libmp3lame)) Link to comment Share on other sites More sharing options...
Luke 37064 Posted October 14, 2017 Share Posted October 14, 2017 So what is the problem? I don't quite understand. The roku is set to stereo and you're getting 2-channel audio, right? Link to comment Share on other sites More sharing options...
ebr 14912 Posted October 14, 2017 Share Posted October 14, 2017 So what is the problem? I don't quite understand. The roku is set to stereo and you're getting 2-channel audio, right? Yeah, this is what I heard too... so I'm confused. Roku is still set to PCM Stereo, has been for a month - this issue just started yesterday though Link to comment Share on other sites More sharing options...
Waldonnis 148 Posted October 14, 2017 Share Posted October 14, 2017 I'm confused too. It's doing exactly what it should be, which is taking a 6-channel AC3 source and transcoding it to 2-channel (using mp3) since the Roku is configured to only output 2-channel audio.... Let's see if we can figure out why the OP may not have expected this, though. Does the soundbar supposedly have a decoder for AC3 built-in even though it's only a 2.1 system? If so, then perhaps an other configuration of your soundbar/television would allow AC3 to pass through untouched (ARC, maybe...if supported). If not, then you're limited to what the Roku can decode codec-wise onboard, which is a rather short list that does not include common surround codecs like ac3 and dts. If the query is more like "why mp3 instead of aac?", then that's a whole other debate... As for the QuickSync warning, disabling QuickSync h.264 decoding will make that go away and probably improve hardware encoding performance. It's a bug that the upstream ffmpeg folks won't acknowledge as a bug (see this trac report) and can cause ffmpeg to use software encoding when it can't establish the context for hardware decoding on some systems (highly dependent on the system configuration). It's really annoying and working around it is a real pain. Link to comment Share on other sites More sharing options...
Nisten 15 Posted October 16, 2017 Author Share Posted October 16, 2017 (edited) I wanted to know what caused this change since the mp3 audio transcoding change only started Last Wednesday/Thursday The PCM configuration has been in place for at least a month so if it was supposed to be converting to mp3 based on my configuration by design, why it only went into effect 4 or 5 days ago? -Soundbar has a AC3 and LPCM decoder Edited October 16, 2017 by Nisten Link to comment Share on other sites More sharing options...
Luke 37064 Posted October 16, 2017 Share Posted October 16, 2017 Why don't we ask this a different way. What are you expecting to happen? Link to comment Share on other sites More sharing options...
Nisten 15 Posted October 16, 2017 Author Share Posted October 16, 2017 I'm expecting it do what its done before, transcoding audio to ac3 - since it was working this way quite a while after i made the PCM changes until last Wednesday/Thursday When it stopped doing what its done before, I wanted to know why it only recently started to take effect -If its supposed to be mp3 based on my setup, then I can start expecting for that to happen instead but just want to know why that change only went into effect only recently even though the PCM changes were made much earlier Link to comment Share on other sites More sharing options...
Solution Jdiesel 1114 Posted October 16, 2017 Solution Share Posted October 16, 2017 (edited) I wanted to know what caused this change since the mp3 audio transcoding change only started Last Wednesday/Thursday The PCM configuration has been in place for at least a month so if it was supposed to be converting to mp3 based on my configuration by design, why it only went into effect 4 or 5 days ago? -Soundbar has a AC3 and LPCM decoder Why it was working that way before I'm not sure but it seems like it may have been a bug that had a positive effect rather than a negative effect. If your soundbar supports ac3 you will want to change your Roku audio settings from "Stereo" to "DD". This way your soundbar will downmix to stereo rather then your server. Was your thinking that because your soundbar was 2 channel you should set your Roku's audio settings to stereo? Just curious. On a side note I noticed some strange things with ac3 a few versions back that seems to have since been fixed, maybe it is related. https://emby.media/community/index.php?/topic/50946-3048-ac3-being-copied/ Edited October 16, 2017 by Jdiesel 1 Link to comment Share on other sites More sharing options...
Nisten 15 Posted October 16, 2017 Author Share Posted October 16, 2017 Changed it to PCM since i don't have the additional audio channels for my soundbar and there's no compression with PCM so DD didn't seem to have any advantages for my setup Out of curiosity @@Jdiesel, what's your sound setup like (both on the hardware and software side) Link to comment Share on other sites More sharing options...
Nisten 15 Posted October 16, 2017 Author Share Posted October 16, 2017 As for the QuickSync warning, disabling QuickSync h.264 decoding will make that go away and probably improve hardware encoding performance. It's a bug that the upstream ffmpeg folks won't acknowledge as a bug (see this trac report) and can cause ffmpeg to use software encoding when it can't establish the context for hardware decoding on some systems (highly dependent on the system configuration). It's really annoying and working around it is a real pain. Thanks for the info, i'll turn that off Link to comment Share on other sites More sharing options...
Jdiesel 1114 Posted October 16, 2017 Share Posted October 16, 2017 Changed it to PCM since i don't have the additional audio channels for my soundbar and there's no compression with PCM so DD didn't seem to have any advantages for my setup Out of curiosity @@Jdiesel, what's your sound setup like (both on the hardware and software side) Mine is likely very similar but instead of a soundbar I have a small 2.1 channel amplifier (http://www.teac.com/product/ai-101da/). The amp does not decode DD or DTS but my TV does. My Roku audio settings are set to (DD, DD+, DTS), My TV is set to output PCM over the optical port, and my amp receives the 2-channel signal. In your case it sounds like your soundbar accepts DD (maybe DTS as well) so you should be able to set the Roku settings to DD, DTS (or whatever your soundbar supports) and have your TV set to passthrough the audio over optical rather then transfer it as PCM. You will need to check your TV's audio settings as every TV is different. 1 Link to comment Share on other sites More sharing options...
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