Most of the shows I have with an original mono source are put on disc with 2 audio channels (AC3 2.0 ch) and I have no issue getting those to direct play. Tom and Jerry is unfortunately 1 channel (AC3 1.0 ch) and Plex on all my Rokus insists on converting them to 2.0 with a throttled direct stream or outright transcoding. Does anybody know an audio setting that would allow these to direct play? I’ve tried AC3 passthru and AAC bitrate 192 and they don’t work.
I’ve been putting a boat-load of Looney Tunes with an AC3 1.0 track - without issue.
The Roku Settings for Audio play a part - a rather large one as that’s the only options you have.
I have :
Audio Mode: Auto Dolby Digital
HDMI: Auto Detect
I have nothing fancy, except a cheap Chinese TV that by a miracle downmixes 5.1 to 2.0 or 1.0 to 2.0 flawlessly. You may not have one of these pieces of Chinese crap, but give it a whirl.
The audio - all of it - has to get to the TV via the HDMI cable, so if that’s not detecting itself automatically, Plex may be trying to transcode something it doesn’t have to.
I guess the idea is to try it automatically - then force the issue if that doesn’t work.
Thanks. Those are the settings I use and they seem to work on everything I have except Tom and Jerry, so I guess I will live with it. I got the same results on a Westinghouse, Insignia, and an Onkyo surround system.
I usually get direct stream throttled on these. I think I got a full transcode on one because it had a ridiculously high bitrate and I didn’t have the Plex on the Roku set to local quality original. This is one of those shows I might have been better off taking your advice about using an average bit rate instead of CQ.
Well, here’s a 7 minute Epic Tail that comes in at a whopping 68MB.
This one looked better than the one on the DVD and plays without issue. Can we see any obvious differences that could cause an issue?
General
Unique ID : 84673764767645080828616556751439452985 (0x3FB392EB91B7A189EA34C4D2FFDADB39)
Complete name : J:\TV-Vintage\Looney Tunes\Season 1949\Looney Tunes - S1949E10 - Mouse Wreckers.mkv
Format : Matroska
Format version : Version 4
File size : 61.6 MiB
Duration : 6 min 55 s
Overall bit rate : 1 245 kb/s
Encoded date : UTC 2020-03-11 20:30:24
Writing application : Lavf58.26.100
Writing library : Lavf58.26.100
ErrorDetectionType : Per level 1
Video
ID : 1
Format : AVC
Format/Info : Advanced Video Codec
Format profile : High@L4.1
Format settings : CABAC / 4 Ref Frames
Format settings, CABAC : Yes
Format settings, Reference frames : 4 frames
Codec ID : V_MPEG4/ISO/AVC
Duration : 6 min 55 s
Bit rate : 1 050 kb/s
Width : 712 pixels
Height : 480 pixels
Display aspect ratio : 4:3
Frame rate mode : Variable
Color space : YUV
Chroma subsampling : 4:2:0
Bit depth : 8 bits
Scan type : Progressive
Stream size : 50.9 MiB (83%)
Writing library : x264 core 157 r2935 545de2f
Encoding settings : cabac=1 / ref=3 / deblock=1:0:0 / analyse=0x3:0x113 / me=hex / subme=7 / psy=1 / psy_rd=1.00:0.00 / mixed_ref=1 / me_range=16 / chroma_me=1 / trellis=1 / 8x8dct=1 / cqm=0 / deadzone=21,11 / fast_pskip=1 / chroma_qp_offset=-2 / threads=12 / lookahead_threads=2 / sliced_threads=0 / nr=0 / decimate=1 / interlaced=0 / bluray_compat=0 / constrained_intra=0 / bframes=3 / b_pyramid=2 / b_adapt=1 / b_bias=0 / direct=1 / weightb=1 / open_gop=0 / weightp=2 / keyint=240 / keyint_min=24 / scenecut=40 / intra_refresh=0 / rc_lookahead=40 / rc=2pass / mbtree=1 / bitrate=1050 / ratetol=1.0 / qcomp=0.60 / qpmin=0 / qpmax=69 / qpstep=4 / cplxblur=20.0 / qblur=0.5 / vbv_maxrate=62500 / vbv_bufsize=78125 / nal_hrd=none / filler=0 / ip_ratio=1.40 / aq=1:1.00
Language : English
Default : Yes
Forced : No
Color range : Limited
Color primaries : BT.601 NTSC
Transfer characteristics : BT.709
Matrix coefficients : BT.601
Audio
ID : 2
Format : AC-3
Format/Info : Audio Coding 3
Commercial name : Dolby Digital
Codec ID : A_AC3
Duration : 6 min 55 s
Bit rate mode : Constant
Bit rate : 192 kb/s
Channel(s) : 1 channel
Channel layout : C
Sampling rate : 48.0 kHz
Frame rate : 31.250 FPS (1536 SPF)
Bit depth : 16 bits
Compression mode : Lossy
Stream size : 9.50 MiB (15%)
Title : Mono
Writing library : Lavc58.46.100 ac3_fixed
Language : English
Service kind : Complete Main
Default : Yes
Forced : No
Text
ID : 3
Format : UTF-8
Codec ID : S_TEXT/UTF8
Codec ID/Info : UTF-8 Plain Text
Duration : 6 min 51 s
Language : English
Default : No
Forced : No
I did run these through Xmedia Recode to bring the level up to 89db for the original track I copied through with Handbrake.
XR might have done something fancy, but I would really know what it is unless we compare.
I can PM you a link to a ‘Sample’ if you’d like to try it.
I’m not really seeing a difference in the audio portion. I do have it encoded as an mp4 instead of an mkv and the original source is a blu-ray. You can PM the link to the sample if you want and I will see if that direct plays. Maybe it is something that XR does.
General
Complete name : \\ERIN-PC\Files2\TV Shows\Tom and Jerry (1940)\Season 1940\Tom And Jerry - S1940e01 - Puss Gets The Boot.mp4
Format : MPEG-4
Format profile : Base Media / Version 2
Codec ID : mp42 (isom/iso2/avc1/mp41)
File size : 224 MiB
Duration : 9 min 16 s
Overall bit rate : 3 371 kb/s
Encoded date : UTC 2020-03-25 21:58:22
Tagged date : UTC 2020-03-25 21:58:22
Writing application : HandBrake 1.3.1 2020010400
Video
ID : 1
Format : AVC
Format/Info : Advanced Video Codec
Format profile : High@L4
Format settings : CABAC / 5 Ref Frames
Format settings, CABAC : Yes
Format settings, Reference : 5 frames
Codec ID : avc1
Codec ID/Info : Advanced Video Coding
Duration : 9 min 13 s
Bit rate : 3 190 kb/s
Width : 1 480 pixels
Height : 1 080 pixels
Display aspect ratio : 1.370
Frame rate mode : Variable
Frame rate : 23.976 (24000/1001) FPS
Minimum frame rate : 23.974 FPS
Maximum frame rate : 23.981 FPS
Color space : YUV
Chroma subsampling : 4:2:0
Bit depth : 8 bits
Scan type : Progressive
Bits/(Pixel*Frame) : 0.083
Stream size : 211 MiB (94%)
Writing library : x264 core 157 r2935 545de2f
Encoding settings : cabac=1 / ref=5 / deblock=1:1:1 / analyse=0x3:0x113 / me=hex / subme=8 / psy=1 / psy_rd=0.40:0.00 / mixed_ref=1 / me_range=16 / chroma_me=1 / trellis=2 / 8x8dct=1 / cqm=0 / deadzone=21,11 / fast_pskip=1 / chroma_qp_offset=-2 / threads=12 / lookahead_threads=2 / sliced_threads=0 / nr=0 / decimate=1 / interlaced=0 / bluray_compat=0 / constrained_intra=0 / bframes=5 / b_pyramid=2 / b_adapt=1 / b_bias=0 / direct=3 / weightb=1 / open_gop=0 / weightp=2 / keyint=240 / keyint_min=24 / scenecut=40 / intra_refresh=0 / rc_lookahead=50 / rc=crf / mbtree=1 / crf=23.0 / qcomp=0.60 / qpmin=0 / qpmax=69 / qpstep=4 / vbv_maxrate=25000 / vbv_bufsize=31250 / crf_max=0.0 / nal_hrd=none / filler=0 / ip_ratio=1.40 / aq=1:0.60
Encoded date : UTC 2020-03-25 21:58:22
Tagged date : UTC 2020-03-25 21:58:22
Color range : Limited
Color primaries : BT.709
Transfer characteristics : BT.709
Matrix coefficients : BT.709
Codec configuration box : avcC
Audio
ID : 2
Format : AC-3
Format/Info : Audio Coding 3
Commercial name : Dolby Digital
Codec ID : ac-3
Duration : 9 min 16 s
Bit rate mode : Constant
Bit rate : 192 kb/s
Channel(s) : 1 channel
Channel layout : C
Sampling rate : 48.0 kHz
Frame rate : 31.250 FPS (1536 SPF)
Compression mode : Lossy
Stream size : 12.7 MiB (6%)
Title : Mono
Language : English
Service kind : Complete Main
Default : Yes
Alternate group : 1
Encoded date : UTC 2020-03-25 21:58:22
Tagged date : UTC 2020-03-25 21:58:22
Make sure you don’t have leveling or night on during playback.
Hit * during playback and make sure all that audio stuff is off - it’ll cause a transcode.
There is a known issue that Roku firmware will always choose the mono stream regardless of the users selection, therefore we defer to transcode to remux the right stream. The issue here is that we missed the case where a video ONLY has a mono stream so there is no reason to defer. We’ll get that fixed in the next update. We also have some fixes that will be able to Direct Play videos having mutliple language streams or streams having the same audio count (as of now, we have to defer to the PMS to remux the selected stream).
Also note, although we will be fixing this, the current method should simply remux (copy) the streams if they are compatible. “throttled direct stream” is a good thing when transcoding. It’s copying the steams and throttled because the server can easily keep up with the conversion. If it’s converting, then it sounds like there may be come incompatibility with the video or maybe the quality in the channel is set too low.
Well, the next update is in! @t2smith please install the Preview channel and let us know if everything is working now. Thanks for the report!
We have pushed a Preview update that should fix the issue. Please let us know how it works for you. Thanks again for the report and sample!
Thanks for all your help. I don’t have leveling or night on.
I will look forward to the next update. The throttled direct stream doesn’t seem to cause me any issues. I only had trouble with a full transcode on a 14.3 Mbps file when the local quality was set to 12 Mbps. I have now set the local quality to original and will be re-encoding to get files that don’t play at such a ridiculously high rate.
By the way, even the 14.3 Mbps file direct plays on the Plex app on my phone.
Just saw your post. Once I figure out how to install the preview update, I will do so and get back to you.
Sounds good. It’s pretty simple, just click the link for Plex Preview and install it that way. It should install immediately on your Roku as a separate channel named Plex Preview with a yellow Preview badge. You can use this and the official version at any time, in case the preview has any issues. If the preview does have any issues, please let us know 
Thank you. I installed the Plex Preview channel and it now direct plays all my videos that have one mono audio stream. I will let you know if I discover any issues.
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