MKV File Audio OK When Played From PC, Garbled When Played From TV

[1voyager1]

I have an MKV file who's audio plays well from my PC.
But, when played from our TV, the audio comes through garbled.

I have run into this before with an AVI file.
I tried converting the audio a few times with no success.

Is there a way to fix this problem?

[awgie]

Need more information.

• What are the specs of the MKV file - specifically what audio codec is used?
• How are you playing it on the TV?
• How are you converting the audio? And to what?

You need to make sure that the audio codec used is compatible with whatever you're using to play it on the TV. Your PC will undoubtedly play dozens of different audio formats just fine, but your TV may not.

[jagabo]

It's a good thing you didn't clutter up your post with information like the model of the TV, the container and audio codecs of the file, how you're playing the video on your TV (media player built into the TV, some other media player, your computer), and stuff like that. It's so much more fun trying to divine that information.

[tugshank]

lol @ jagabo. are you using a crystal ball? is it 4k though?

[1voyager1]

Yeah I know, I didn't give much information.
But then, I wasn't sure exactly what was needed to figure this out.

1.
How do I find what is contained in the MKV file?

2.
The TV is a JVC SP55M-C.
I believe that it does auto firmware updates.
The first time I loaded an MKV file into it and it accepted it I was very surprised.
I have gone through the menu and cannot see where acceptable audio codecs are listed.

The video files are 720 or 1080, entered into the TV by way of a thumb drive and are accessed through the remote's "Multimedia" button.

How do I find out what audio codecs are accepted by the TV?

OK, will that give us enough to get started with?

[jagabo]

Use MediaInfo to determine the audio and video codecs (problems with the video codec can cause audio problems too). Use text mode in MediaInfo (View -> Text) then cut/paste into a message here.

[1voyager1]

OK, here is the MediaInfo text file for that video:

General
Unique ID : 211026911985641282490607912847662307987 (0x9EC24E0D0A309D1DA7D5647FC5F6DA93)
Complete name : C:\Users\Solo-1\Desktop\Video 01.mkv
Format : Matroska
Format version : Version 4 / Version 2
File size : 1.76 GiB
Duration : 1 h 52 min
Overall bit rate mode : Variable
Overall bit rate : 2 244 kb/s
Encoded date : UTC 2016-12-29 05:16:55
Writing application : mkvmerge v9.4.0 ('Knurl') 32bit
Writing library : libebml v1.3.4 + libmatroska v1.4.5

Video
ID : 1
Format : AVC
Format/Info : Advanced Video Codec
Format profile : High@L4.2
Format settings, CABAC : Yes
Format settings, ReFrames : 4 frames
Codec ID : V_MPEG4/ISO/AVC
Duration : 1 h 52 min
Bit rate mode : Variable
Bit rate : 2 000 kb/s
Maximum bit rate : 62.5 Mb/s
Width : 720 pixels
Height : 384 pixels
Display aspect ratio : 1.85:1
Frame rate mode : Constant
Frame rate : 23.976 (24000/1001) FPS
Color space : YUV
Chroma subsampling : 4:2:0
Bit depth : 8 bits
Scan type : Progressive
Bits/(Pixel*Frame) : 0.302
Stream size : 1.55 GiB (89%)
Writing library : x264 core 148 r2638 7599210
Encoding settings : cabac=1 / ref=5 / deblock=1:0:0 / analyse=0x3:0x133 / me=umh / subme=9 / psy=1 / psy_rd=1.00:0.00 / mixed_ref=1 / me_range=18 / chroma_me=1 / trellis=2 / 8x8dct=1 / cqm=0 / deadzone=21,11 / fast_pskip=0 / chroma_qp_offset=-2 / threads=16 / lookahead_threads=1 / sliced_threads=0 / slices=4 / nr=0 / decimate=1 / interlaced=0 / bluray_compat=0 / constrained_intra=0 / bframes=3 / b_pyramid=1 / b_adapt=2 / b_bias=0 / direct=3 / weightb=1 / open_gop=0 / weightp=2 / keyint=240 / keyint_min=23 / scenecut=40 / intra_refresh=0 / rc_lookahead=40 / rc=abr / mbtree=1 / bitrate=2000 / ratetol=1.0 / qcomp=0.60 / qpmin=10 / qpmax=51 / qpstep=4 / vbv_maxrate=62500 / vbv_bufsize=78125 / nal_hrd=vbr / filler=0 / ip_ratio=1.40 / aq=1:1.00
Default : Yes
Forced : No
Color range : Full
Color primaries : BT.709
Transfer characteristics : BT.709
Matrix coefficients : BT.709

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 : 1 h 52 min
Bit rate mode : Constant
Bit rate : 256 kb/s
Channel(s) : 2 channels
Channel positions : Front: L R
Sampling rate : 44.1 kHz
Frame rate : 28.711 FPS (1536 spf)
Bit depth : 16 bits
Compression mode : Lossy
Delay relative to video : 24 ms

[jagabo]

I don't see anything there that looks like it would be a problem. What do you mean by "garbled"? Is it just an occasional chirp or is it continuously bad? Can you recognize the audio at all?

Try a quick remux with mkvtoolnix. Just open the video and save as a new video.

Also, as a test, try muxing the audio with another video, one that plays normally. See if the problem follows the audio or the video.

[awgie]

2.
The TV is a JVC SP55M-C.
I believe that it does auto firmware updates.
The first time I loaded an MKV file into it and it accepted it I was very surprised.
I have gone through the menu and cannot see where acceptable audio codecs are listed.

The video files are 720 or 1080, entered into the TV by way of a thumb drive and are accessed through the remote's "Multimedia" button.

How do I find out what audio codecs are accepted by the TV?

OK, will that give us enough to get started with?

Page 32 of the user manual says the following:

The TV is capable of photos, music and video playback. However, due to the wide variety of multimedia file formats. Some formats may not be supported.

Unfortunately it doesn't say which formats are supported.

However, according to the FAQs for JVC TVs (http://www.jvc-tv.com/faq/), they only support .MP4 files, so the fact that it would play an .MKV file at all is indeed a surprise. I suspect this is the root of your problem.

According to the user manual for that TV (page 55, "Audio Technology"), it does do Dolby audio, which is what AC3 is, so if you use a program such as AviDemux or maybe ffmpeg to take the AVC video stream and the AC3 audio stream and simply put them into an .MP4 container, you should be able to play the file just fine without needing to completely re-encode it.

[1voyager1]

Sorry for disappearing for so long. Other more pressing matters came up.

I tried converting the video to MPEG4, then XVID .mp4, and the audio to mp3 in both cases.
No satisfaction.
Audio still garbled.
Distorted may be a better term.

I found another copy from another source and tried it.
It works just fine on both PC and TV.

MediaInfo text file for video 02:
General
Complete name : C:\Users\Solo-1\Desktop\Video 02.avi
Format : AVI
Format/Info : Audio Video Interleave
File size : 1.36 GiB
Duration : 1 h 52 min
Overall bit rate : 1 736 kb/s
Writing library : VirtualDub build 32593/release

Video
ID : 0
Format : MPEG-4 Visual
Format profile : Advanced Simple@L5
Format settings, BVOP : 2
Format settings, QPel : No
Format settings, GMC : No warppoints
Format settings, Matrix : Default (H.263)
Muxing mode : Packed bitstream
Codec ID : XVID
Codec ID/Hint : XviD
Duration : 1 h 52 min
Bit rate : 1 343 kb/s
Width : 720 pixels
Height : 384 pixels
Display aspect ratio : 1.85:1
Frame rate : 23.976 (24000/1001) FPS
Color space : YUV
Chroma subsampling : 4:2:0
Bit depth : 8 bits
Scan type : Progressive
Compression mode : Lossy
Bits/(Pixel*Frame) : 0.203
Stream size : 1.05 GiB (77%)
Writing library : XviD 66

Audio
ID : 1
Format : AC-3
Format/Info : Audio Coding 3
Mode extension : CM (complete main)
Format settings, Endianness : Big
Codec ID : 2000
Duration : 1 h 52 min
Bit rate mode : Constant
Bit rate : 384 kb/s
Channel(s) : 6 channels
Channel positions : Front: L C R, Side: L R, LFE
Sampling rate : 48.0 kHz
Frame rate : 31.250 FPS (1536 spf)

I've used video 02 and deleted 01.
I don't know enough to see why one works and the other doesn't.

Thank you for your help on this folks.
You've given me some useful information I can use in the future, even if I haven't used it all now.

[awgie]

Sorry for disappearing for so long. Other more pressing matters came up.

I tried converting the video to MPEG4, then XVID .mp4, and the audio to mp3 in both cases.
No satisfaction.
Audio still garbled.
Distorted may be a better term.

The video was already MPEG4 format

Video
ID : 1
Format : AVC
Format/Info : Advanced Video Codec
Format profile : High@L4.2
Format settings, CABAC : Yes
Format settings, ReFrames : 4 frames
Codec ID : V_MPEG4/ISO/AVC

• When you did these 2 conversions, what were the steps you performed?
• What software did you use?
• Did you put them back into an MKV container, or leave them as .MP4?
• Did the resulting MP3 audio sound OK on your computer?

I've used video 02 and deleted 01.

That's unfortunate. It would be nice to try other things out on Video 01.

Specifically, I noticed that the audio showed the A_AC3 codec, and that may be what is messing it up. A_AC3 is specific to Matroska (.mkv) files. Normal AC3 is BitStreamID 8, but A_AC3 also allows for BSID9 & BSID10, which break decoder compatibility. Your audio may in fact be BSID8, but showing A_AC3 as the codec may be throwing everything off.

Your TV may not be compatible with it, and the software you used to convert it to MP3 may also not be reading it correctly, resulting in the MP3 also being messed up.

I found another forum thread mentioning having problems with A_AC3 audio, and the suggestion was made to try MKV2AC3. Unfortunately, the OP never updated whether it was successful.