PS3 - AC3 Audio Streams in Stereo

First, thanks for the fun piece of software. It's pretty amazing.

Sorry if this is a dunce question, but I've tried to find my answer via various Google & forum searches to no avail.

I can't figure out why my DVD rip with MPEG2 video and AC3 audio wrapped in an MKV is streaming fine to my PS3, but only in stereo - i.e. no 5.1 Surround Sound. There is only one audio track in the MKV as follows:

  Code:

General
Unique ID                                : 176451987582924010351171111030130009725 (0x84BF6AAA718250E8BB3C6A8BC868E67D)
Complete name                            : H:\Media\Video\Movies\Groundhog Day.mkv
Format                                   : Matroska
Format version                           : Version 4 / Version 2
File size                                : 5.11 GiB
Duration                                 : 1h 41mn
Overall bit rate mode                    : Variable
Overall bit rate                         : 7 244 Kbps
Encoded date                             : UTC 2014-02-24 01:57:58
Writing application                      : mkvmerge v6.7.0 ('Back to the Ground') 32bit built on Jan  8 2014 15:03:17
Writing library                          : libebml v1.3.0 + libmatroska v1.4.1

Video
ID                                       : 1
Format                                   : MPEG Video
Format version                           : Version 2
Format profile                           : Main@Main
Format settings, BVOP                    : No
Format settings, Matrix                  : Custom
Codec ID                                 : V_MPEG2
Codec ID/Info                            : MPEG 1 or 2 Video
Duration                                 : 1h 41mn
Bit rate mode                            : Variable
Bit rate                                 : 6 652 Kbps
Maximum bit rate                         : 9 800 Kbps
Width                                    : 720 pixels
Height                                   : 480 pixels
Display aspect ratio                     : 16:9
Frame rate mode                          : Constant
Frame rate                               : 29.970 fps
Standard                                 : NTSC
Color space                              : YUV
Chroma subsampling                       : 4:2:0
Bit depth                                : 8 bits
Scan type                                : Interlaced
Scan order                               : Top Field First
Compression mode                         : Lossy
Bits/(Pixel*Frame)                       : 0.642
Time code of first frame                 : 00:00:00:00
Time code source                         : Group of pictures header
Stream size                              : 4.70 GiB (92%)
Default                                  : Yes
Forced                                   : No

Audio
ID                                       : 2
Format                                   : AC-3
Format/Info                              : Audio Coding 3
Mode extension                           : CM (complete main)
Format settings, Endianness              : Big
Codec ID                                 : A_AC3
Duration                                 : 1h 41mn
Bit rate mode                            : Constant
Bit rate                                 : 448 Kbps
Channel(s)                               : 6 channels
Channel positions                        : Front: L C R, Side: L R, LFE
Sampling rate                            : 48.0 KHz
Bit depth                                : 16 bits
Compression mode                         : Lossy
Stream size                              : 324 MiB (6%)
Default                                  : Yes
Forced                                   : No



My Rendering Profile is set to Playstation 3. I do have an H264 BluRay rip with the same type of AC3 audio (though at a higher bitrate) that streams great with 5.1, so my guess is that the Profile.xml is doing something based on the video type? I'm not a programmer, so trying to parse what the Profile.xml is doing is kind of like reading a foreign language...

Any help is much appreciated. Feel free to point me to another thread if this has been discussed to death somewhere that I couldn't find.

[Illico]

Could you check on serviio console "transcoding" tag that you don't enable audio "downmix to stereo" ?

Could you check on serviio console "transcoding" tag that you don't enable audio "downmix to stereo" ?

Thanks for the response and sorry for the delay - had a long day at work today!

Anyway, on the "Transcoding" tab under "Video Settings", "Produce the best video quality" box is checked and "Keep Original" is selected for "Audio channels".

I think I figured it out! Well, partially anyway...

Original (relevant portion of the) PS3 section of profiles.xml looked like:

  Code:

         <!--
            remux MKV with any video to MPEG2TS and possibly change audio to ac3, also AVI and FLV with H264
         -->
         <Video targetContainer="mpegts" targetACodec="ac3" aBitrate="384">
            <Matches container="matroska" />
            <Matches container="avi" vCodec="h264" />
            <Matches container="flv" vCodec="h264" />
            <Matches container="3gp" vCodec="h264" />
         </Video>
         <Video targetContainer="mpegts" >
            <Matches container="wtv" />
            <Matches container="asf" vCodec="mpeg2video"/> <!--  dvr-ms -->            
         </Video>

I changed it to look like (cut & paste the "matroska" line below "mpegts" so it no longer tries to do anything to the audio stream):

  Code:

         <!--
            remux MKV with any video to MPEG2TS and possibly change audio to ac3, also AVI and FLV with H264
         -->
         <Video targetContainer="mpegts" targetACodec="ac3" aBitrate="384">
            <Matches container="avi" vCodec="h264" />
            <Matches container="flv" vCodec="h264" />
            <Matches container="3gp" vCodec="h264" />
         </Video>
         <Video targetContainer="mpegts" >
            <Matches container="matroska" />
            <Matches container="wtv" />
            <Matches container="asf" vCodec="mpeg2video"/> <!--  dvr-ms -->            
         </Video>

and it now streams in 5.1 Surround. Obviously, this will only work as long as I continue to feed it streams with compatible AC3 audio, but that's my intent. Are you aware of a better way to do this?

Also, I still don't understand where the profiles.xml was capturing the BluRay (H.264/MPEG-4 AVC wrapped in an MKV) stream and treating it differently (i.e. playing 5.1 as expected)?

[DenyAll]

Just chiming in as I'm online... this is interesting as the AC3 should not be re-encoded. Serviio should, on detecting AC3, not re-encode it (which is what would be happening on your other MKV files). It would be intesting to see what ffmpeg sees the file as (do an ffmpeg - i on the file). If it does detect it as AC-3 then it could be a bug, or something specific to the mpeg2/ac3 combination in Serviio - something for zip to look at perhaps.

Are you aware of a better way to do this?

I would do it as:

  Code:

         <Video targetContainer="mpegts" >
            <Matches container="matroska" vCodec="mpeg2video" aCodec="ac3"/>
            <Matches container="wtv" />
            <Matches container="asf" vCodec="mpeg2video"/> <!--  dvr-ms -->           
         </Video>
         <!--
            remux MKV with any video to MPEG2TS and possibly change audio to ac3, also AVI and FLV with H264
         -->
         <Video targetContainer="mpegts" targetACodec="ac3" aBitrate="384">
            <Matches container="matroska" />
            <Matches container="avi" vCodec="h264" />
            <Matches container="flv" vCodec="h264" />
            <Matches container="3gp" vCodec="h264" />
         </Video>

as this will then still pick up all mpeg2, non-AC3 MKV's while specifically dealing with your problem. Note the swap in order of the sections - Serviio deals with match statements in order. You may have to remove the aCodec="ac3" bit (as the problem may be that it's not being detected properly).

Just chiming in as I'm online... this is interesting as the AC3 should not be re-encoded. Serviio should, on detecting AC3, not re-encode it

LoL... thanks for chiming in as it appears you read my mind. I was thinking about this again this morning, and I kept harping on the same conclusion that you just stated. I logged in to throw it out there, but your proactive stance made this simpler.

It would be intesting to see what ffmpeg sees the file as (do an ffmpeg - i on the file). If it does detect it as AC-3 then it could be a bug, or something specific to the mpeg2/ac3 combination in Serviio - something for zip to look at perhaps.

I will do this tonight and report back.

I would do it as: .... this will then still pick up all mpeg2, non-AC3 MKV's while specifically dealing with your problem.

Thanks - a much better workaround. I'll also try this tonight and report back my findings.

I admit that I'm pretty new to the whole "rip a DVD and stream it to PS3" thing, but I do try to learn as much as I can when something interests me. This is interesting stuff. I'm wondering - with the popularity of PS3's, DVDs, and now streaming, does this feel like a "new issue" simply because I'm doing something differently than the more experienced veterans - i.e. do most vets not use MKV's for example? It seems a pretty straightforward workflow to me which is what attracted me to that wrapper.

I know that's a pretty open-ended question as everyone's likely to do something a little differently and/or use different software packages to accomplish the same thing. Mostly just thinking out loud.

Thanks again.

[DenyAll]

No drama - happy to help. Most people nowadays either rip to MKV's or MP4's, and there is hours of debate on the web about the relative merits of each

imo the main game though is what containers, video and audio does your renderer devices support. I'm not sure what other devices you have, but the PS3 for example supports MP4 files natively (whereas it requires MKVs to be transcoded) so you may want to consider using an MP4 container if the PS3 is your main/only renderer. One thing I did notice in your MKV posted above though is the use of the mpeg2 video codec - this is not common - almost everyone today is using h264. The PS3 natively supports MP4 with h264 video (up to profile level 4.1) and AAC or AC3 audio.

It would be intesting to see what ffmpeg sees the file as (do an ffmpeg - i on the file). If it does detect it as AC-3 then it could be a bug, or something specific to the mpeg2/ac3 combination in Serviio - something for zip to look at perhaps.

Here's the ffmpeg info:

  Code:

Input #0, matroska,webm, from 'groundhog day.mkv':
  Metadata:
    creation_time   : 2014-02-24 01:57:58
  Duration: 01:41:04.06, start: 0.000000, bitrate: 7244 kb/s
    Stream #0:0: Video: mpeg2video (Main), yuv420p, 720x480 [SAR 32:27 DAR 16:9]
, SAR 186:157 DAR 279:157, 59.94 fps, 59.94 tbr, 1k tbn, 59.94 tbc (default)
    Stream #0:1: Audio: ac3, 48000 Hz, 5.1(side), fltp, 448 kb/s (default)


Looks like it's definitely AC-3 audio, so it might be a bug as you suggested.

so it might be a bug as you suggested.

Okay, now I'm going to look like an idiot, but I can not repeat the problem. I changed the profile.xml back to the default in order to test a different file, restarted the Serviio service, and on a whim tried to play the file from my original post. It played fine with 5.1 surround. I turned off the PS3, rebooted my PC, double-checked that I was indeed using the default profile.xml, restarted the PS3, played the movie - and it's fine.

I can't explain this, but I'm fairly certain I saw the behavior that I originally posted about. I'm going to go hide now.

One thing I did notice in your MKV posted above though is the use of the mpeg2 video codec - this is not common - almost everyone today is using h264.

I did want to expand on this a bit. I used MakeMKV to rip the DVD. My understanding based on my reading is that MakeMKV doesn't do any transcoding - it just takes the native files you select from the DVD, removes the copy protection and wraps it into an MKV file with the audio track/s you select. In the case of DVD, it appears to also stitch the VOB's together in order to create one video file from the multiple 1Gb VOB's. My understanding could be dead wrong...

Anyway, my point is that the video format you see was what MKV extracted from the DVD, so I assumed that was the "native" video codec that was used on the DVD. I don't want to transcode anything (yet) without understanding what and why I was doing it as I believe transcoding results in a generational quality degradation?

btw, thanks for the additional insight into formats - I'll definitely be doing some more reading... I'm still in the "experimenting" phase of all this.