Audio Sync Problem

I’ve read many other posts on this problem but haven’t seen anything productive in the way of a solution. However, I’d like to add some info from my research and ask if I have missed any solutions.

I have the older WDTV (with the latest firmware) and am seeing audio sync problems on both MP4 and MKV files. I saw the same issue on the previous firmware too. In all cases, the videos play perfectly in a variety of video players on my Windows PC. When I play them either on the USB HD over the network via Network Shares, I see the audio sync problem.

Here’s what I have done:

  1. Original MKV file previously recorded from the HDTV (5.1 audio) - out of sync

  2. Recoded to MP4 (downmix to 2 channel audio) - still out of sync but not as bad.

  3. Recoded to .ts format (5.1 audio) - not perfect but almost perfect sync)

Does this provide any help?

Have I missed any obvious solutions?

How is the audio / video of your WDTV hooked up?

The WDTVis  connected to TV as follows:

WDTV - HDMI - A/V receiver - HDMI - HDTV

You are probably wondering if the sync problem could be caused the the connection to the TV.

I suspect not because most other video files are synced properly. I have dozens of videos that are permanently stored on the HD connected to the WDTV. There are many more that have been there temporarily until they are viewed. 

I have never had a sync problem with other file formats (TS, M2TS, MPG, AVI, VOB) Most have been 5.1 audio. I’ve ocassionally had a sync problem on MP4 files. However, it happens more frequently (but not always) on MKV files. When I do have a sync problem on an MKV file, it is consistent. i.e. every time I play it. If there is no sync problem, then that too is consistent.

Therefore, my assumption is that the problem is related to the MKV video not the link to the TV. In addition, since there is no sync problem when the video is played on the computer, I assume that the problem is created by the manner in which the WDTV handles that video file. I can’t be 100% certain because I haven’t kept track but I believe that the sync problem is only on 5.1 audio files.

If it is any help, here is the media indo for the latest video that is out of sync:

Unique ID : 31011400716759712653604795565939532869 (0x1754941A43F8B35AB1F52A3543A2A445)
Complete name : D:\My Documents\ **************.mkv

Format : Matroska
Format version : Version 2
File size : 1.26 GiB
Duration : 41mn 26s
Overall bit rate : 4 367 Kbps
Encoded date : UTC 2012-12-11 03:32:37
Writing application : mkvmerge v3.0.0 (‘Hang up your Hang-Ups’) built on Apr 19 2010 11:58:49
Writing library : libebml v0.7.7 + libmatroska v0.8.1

ID : 1
Format : AVC
Format/Info : Advanced Video Codec
Format profile : High@L4.1
Format settings, CABAC : Yes
Format settings, ReFrames : 5 frames
Duration : 41mn 26s
Bit rate : 3 897 Kbps
Width : 1 280 pixels
Height : 720 pixels
Display aspect ratio : 16:9
Frame rate mode : Constant
Frame rate : 59.880 fps
Original frame rate : 59.940 fps
Color space : YUV
Chroma subsampling : 4:2:0
Bit depth : 8 bits
Scan type : Progressive
Bits/(Pixel*Frame) : 0.071
Stream size : 1.13 GiB (89%)
Writing library : x264 core 129 r2230 1cffe9f
Encoding settings : cabac=1 / ref=5 / deblock=1:2:2 / analyse=0x3:0x113 / me=umh / subme=8 / psy=1 / psy_rd=1.00:0.00 / mixed_ref=1 / me_range=20 / chroma_me=1 / trellis=1 / 8x8dct=1 / cqm=0 / deadzone=21,11 / fast_pskip=0 / 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=2 / b_bias=0 / direct=3 / weightb=1 / open_gop=0 / weightp=2 / keyint=250 / keyint_min=25 / scenecut=40 / intra_refresh=0 / rc_lookahead=50 / rc=crf / mbtree=1 / crf=20.0 / qcomp=0.60 / qpmin=0 / qpmax=69 / qpstep=4 / ip_ratio=1.40 / aq=1:1.00
Language : English
Default : No
Forced : No
Matrix coefficients : BT.709

ID : 2
Format : AC-3
Format/Info : Audio Coding 3
Mode extension : CM (complete main)
Format settings, Endianness : Big
Codec ID : A_AC3
Duration : 41mn 26s
Bit rate mode : Constant
Bit rate : 384 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 : 114 MiB (9%)
Default : Yes
Forced : No


do you have the same problem if you connect your player directly to the tv.


do you have the same problem if you connect your player directly to the tv.

I just rewired and tried it. Yes. I still have the out of sync problem.

For giggles, turn off *ALL* image processing functions on your TV.   The LG accomplishes this through a mode called “Game Mode.”

That will significantly reduce image decode latency.

maybe the way the file was encoded is the cause of sync problem ?

dodgy looking framerates …

Frame rate : 59.880 fps
Original frame rate : 59.940 fps



all my files are either  23.976fps / 24.000fps 25.000fps / and 29.970fps 


For giggles, turn off *ALL* image processing functions on your TV. 


I didn’t want to cloud the thread with unnecessary detail but I didn’t really wire the WDTV directly to the TV. It wouldn’t have done any good. The TV is set up as a monitor only (i.e. no speakers). If I wired directly to the TV, I would have had to either wire audio separtely to the A/V receiver or wire the audio output from the TV to the A/V receiver. Therefore, I would have had the same audio processing one way or the other. Instead, I took one of my computer monitors (with speakers included) and wired the HDMI from the WDTV to the computer monitor. I had the same level of delay. (The caution here is that the computer monitor has only stereo speakes not 5.1???) Therefore, I believe that the issue is the manner in which the WDTV handles the video file.


maybe the way the file was encoded is the cause of sync problem ?

dodgy looking framerates …

Frame rate : 59.880 fps
Original frame rate : 59.940 fps



My re-encoded TS file has a frame rate of 59.940. i.e. exactly the same as the original frame rate. It is closer to the standard 60 fps. That file still has a small sync issue but not nearly as bad ar the MKV file with a 59.880 fps. 


If nothing else comes of this thread, I’ll keep a close watch on future videos. I’ll check the frame rate of every one to see if the sync problem corresponds to the frame rate. It may be a while before I have enough empirical evidence but I’ll post back with the results.