Audio and Video Out Of Sync - .M2TS Files -

Hello,

I’ve been working with WD support on the issue where the audio does not start playing for 3-10 seconds after the video starts.  This occurs with .M2TS files copied directly from my Sony HD camcorder onto the HUB hard drive and also when streaming the same file from a network share.  Once in sync, they seem to play OK for the duration.  Anyone else having this problem?

What Audio Codec does your camera use?

I have seen something similar with a Dolby Digital+ track, but it only took about 3 seconds to start audio.   It was never out of sync, per se; just silent for those seconds.

I also have the same problem regarding a 2-3 second delay in synch between the video and audio for my .m2ts files.  BTW, my files are ripped versions of my “purchased” Blu Ray discs.  I don’t consider it to be a big deal but it is a little annoying.

General
ID                               : 0
Complete name                    : 20101107134755.m2ts
Format                           : BDAV
Format/Info                      : Blu-ray Video
File size                        : 209 MiB
Duration                         : 1mn 41s
Overall bit rate                 : 17.3 Mbps
Maximum Overall bit rate         : 18.0 Mbps

Video
ID                               : 4113 (0x1011)
Menu ID                          : 1 (0x1)
Format                           : AVC
Format/Info                      : Advanced Video Codec
Format profile                   : High@L4.0
Format settings, CABAC           : Yes
Format settings, ReFrames        : 2 frames
Format settings, GOP             : M=1, N=30
Codec ID                         : 27
Duration                         : 1mn 41s
Bit rate mode                    : Variable
Bit rate                         : 16.2 Mbps
Maximum bit rate                 : 16.0 Mbps
Width                            : 1 920 pixels
Height                           : 1 080 pixels
Display aspect ratio             : 16:9
Frame rate                       : 29.970 fps
Color space                      : YUV
Chroma subsampling               : 4:2:0
Bit depth                        : 8 bits
Scan type                        : Interlaced
Scan order                       : Top Field First
Bits/(Pixel*Frame)               : 0.260
Stream size                      : 195 MiB (93%)

Audio
ID                               : 4352 (0x1100)
Menu ID                          : 1 (0x1)
Format                           : AC-3
Format/Info                      : Audio Coding 3
Mode extension                   : CM (complete main)
Codec ID                         : 129
Duration                         : 1mn 41s
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
Video delay                      : -67ms
Stream size                      : 5.40 MiB (3%)

Text
ID                               : 4608 (0x1200)
Menu ID                          : 1 (0x1)
Format                           : PGS
Codec ID                         : 144
Duration                         : 1mn 40s
Video delay                      : -67ms

I experienced a similar anomaly playing a .M2TS file (1080p DTS HD) over my network (Ethernet).  However, when the same file was played from the internal harddrive there was no lag between video and sound.

Streamed over my network (Ethernet) there was a six second delay before the wdtv identified the sound track and displayed it to screen, Once the sound track was identified sound and video were in synch. 

Obviously WD support gets the last say in what’s going on, but what I think’s happening is that the video has to be buffered ahead of the audio to ensure they all get played back together, because the audio is CBR while the video is VBR and the chunks won’t necessarily line up, and the chip needs to pay much more attention to what it’s doing with the video decoding.

In theory, the device could do all the pre-playback preparations and then start both streams simultaneously (like a stand-alone BR player generally would), but I’m not sure if the WD’s have the buffer space and processing capacity to actually do this – the video data might eat up all the available buffer space.  This might be one of those issues that the engineers can’t do much with.

And, with the transfer rates, that would also be why it’s sometimes worse networked… it’s doing the same look-ahead, but the data’s slower in coming in.

If WD can’t do much with it (and as of now, that’s just guesswork on my part), the only real workaround would be to re-code the files to a different container, so that the streams are chunked and multiplexed differently, and the WD has to do less look-ahead buffering.

Hi,

I just posted a similar complaint with regards to *.mts files from my JVC camera…i.e. which are also, according the MediaInfo data, BDAV (Blu-ray video). In my case after pressing okay to start the video one approximately experiences the following:

  • for 5 seconds one sees the video playing but with muted audio.

  • after 5 seconds the video freezes and audio starts up and I observed this audio to be the audio content from the first (i.e. or previous) 5 seconds

  • finally after around 10 seconds the audio and video sync up and start playing together.

It would be better for player to mute both the audio and video at start up to allow everything to sync and then gracefully play the sync’ed content from the very beginning i.e. so one could cleanly view the first 10 seconds of the video file.

Charles

Having retype this all in for the 2nd time…i.e. my session crashed. Decided to type into Word pad and copy and paste so I don’t lose all this a 2nd time.

I think I have some new information/observations to add to this problem.

I finally got around to loading MeGui on my computer today. I used MeGUI to demux the video and audio from a blu-ray *.mts file that has an out of sync start of issue with the WD TV Live Hub player (i.e. see previous post). In fact all the files from my JVC camera do not work correctly in the player (i.e. first 10 seconds of every video file).

After demuxing the video and audio I muxed them back together into a Blu-ray *.m2ts file. I tried playing the file on the WD TV Live Hub and to my delight there was no 10s start up skew i.e. the file play correctly from the start. So then I was curious to determine what was different between the two files. I compared the MediaInfo data of the two files i.e. the original *.mts file from my JVC camera and the new ('remux’ed) *.m2ts file I’d created using MeGUI.

They are both Blu-ray files and show no significant difference other than the fact that the original *.mts file includes a -67ms video delay.   mmmm…could this be the thing that is contributing to the problem. Note that the re-muxed *.m2ts file created using MeGUI does not have this delay. Other than this there is no significant difference between the files. The only other difference that may or may not be significant is that the original *.mts file include a test component that I didn’t include in the re-muxed file. I’ve include the MediaInfo data for both files below:

-------> Original file ------>

General

ID : 0

Complete name : D:\My Video\Everio\HDDCAM\20100614\9657687925919318016\00084.mts

Format : BDAV

Format/Info : Blu-ray Video

File size : 94.9 MiB

Duration : 2mn 37s

Overall bit rate : 5 062 Kbps

Maximum Overall bit rate : 18.0 Mbps

Video

ID : 4113 (0x1011)

Menu ID : 1 (0x1)

Format : AVC

Format/Info : Advanced Video Codec

Format profile : High@L4.0

Format settings, CABAC : No

Format settings, ReFrames : 2 frames

Format settings, GOP : M=1, N=30

Codec ID : 27

Duration : 2mn 37s

Bit rate mode : Variable

Bit rate : 4 595 Kbps

Maximum bit rate : 17.0 Mbps

Width : 1 920 pixels

Height : 1 080 pixels

Display aspect ratio : 16:9

Frame rate : 29.970 fps

Color space : YUV

Chroma subsampling : 4:2:0

Bit depth : 8 bits

Scan type : Interlaced

Scan order : Top Field First

Bits/(Pixel*Frame) : 0.074

Stream size : 86.0 MiB (91%)

Audio

ID : 4352 (0x1100)

Menu ID : 1 (0x1)

Format : AC-3

Format/Info : Audio Coding 3

Mode extension : CM (complete main)

Codec ID : 129

Duration : 2mn 37s

Bit rate mode : Constant

Bit rate : 256 Kbps

Channel(s) : 2 channels

Channel positions : Front: L R

Sampling rate : 48.0 KHz

Bit depth : 16 bits

Video delay : -67ms

Stream size : 4.80 MiB (5%)

Text

ID : 4608 (0x1200)

Menu ID : 1 (0x1)

Format : PGS

Codec ID : 144

Duration : 2mn 36s

Video delay : -67ms

----------> MeGui file ------>

General

ID : 1

Complete name : D:\My Video\temporary\Megui test\0084_megui.m2ts

Format : BDAV

Format/Info : Blu-ray Video

File size : 92.0 MiB

Duration : 2mn 37s

Overall bit rate : 4 909 Kbps

Maximum Overall bit rate : 35.5 Mbps

Video

ID : 4113 (0x1011)

Menu ID : 1 (0x1)

Format : AVC

Format/Info : Advanced Video Codec

Format profile : High@L4.0

Format settings, CABAC : No

Format settings, ReFrames : 2 frames

Format settings, GOP : M=1, N=30

Codec ID : 27

Duration : 2mn 36s

Bit rate mode : Variable

Bit rate : 4 450 Kbps

Maximum bit rate : 17.0 Mbps

Width : 1 920 pixels

Height : 1 080 pixels

Display aspect ratio : 16:9

Frame rate : 29.970 fps

Color space : YUV

Chroma subsampling : 4:2:0

Bit depth : 8 bits

Scan type : Interlaced

Scan order : Top Field First

Bits/(Pixel*Frame) : 0.072

Stream size : 83.3 MiB (91%)

Audio

ID : 4352 (0x1100)

Menu ID : 1 (0x1)

Format : AC-3

Format/Info : Audio Coding 3

Mode extension : CM (complete main)

Codec ID : 129

Duration : 2mn 37s

Bit rate mode : Constant

Bit rate : 256 Kbps

Channel(s) : 2 channels

Channel positions : Front: L R

Sampling rate : 48.0 KHz

Bit depth : 16 bits

Stream size : 4.80 MiB (5%)

I believe MeGUI may allow one to stipulate a video delay when muxing audio and video…if I can make that work…I will try an create the same file with the delay to confirm if the problem comes back.

Charles

67ms is significant to some people.  That’s about TWO FRAMES of video.   Does that sound about right? (No pun intended)

I think the MINUS means the video should PRECEDE the audio track by 67ms, but I’m not sure.

I’m having the same problem with .mt2s files.  I’m running latest firmware, cabled network.  Accessing the files through media server or network shares doesn’t matter - still get the 5 second delay.  Using a USB drive attached to the WDTV the sync issue goes away.  From everything I’ve read this appears to be a limitation on the WDTV itself, but before returning it I wanted to see if there was any new update or fix? 

Thanks,

Matt

having the identical issue here running off a wired network playing back  .M2TS files from a SONY hd camcorder

"- for 5 seconds one sees the video playing but with muted audio.

- after 5 seconds the video freezes and audio starts up and I observed this audio to be the audio content from the first (i.e. or previous) 5 seconds

- finally after around 10 seconds the audio and video sync up and start playing together."

the weird part is these files used to play back just fine before the latest firmware updates

once several seconds go by the video/audio plays back fine and fully synced but the play/pause is annoying when trying to browse through a bunch of videos

haven’t tried rolling back to old firmware yet

I am facing the exact same issue with M2TS files from Canon HD Camcorder. Does anyone know solution for this?

the problem is that the video is recorded with those -67 ms of delay.

Solution is ,

1 - use tmuxerR (free tool) to convert the file to .M2TS 

2 - if u have several files and u want to merge them all together , use tmuxeR to merge them.

by using that tool the delay issue is fixed ,at least all my videos now doesnt have that delay.

Hi, Pumper

I’ve just got the WD TV Live Plus media player, and I’m having the same problem as you did.  I’m interested to know which particular version of firmware doesn’t have this problem as you said it worked fine before the latest firmware update.  Thus I can try to fix this problem.  Many thanks.

i really wish there was an audio lag adjustment feature. Some of my movies are off by a second or two when watching on my WDTV thru HDMI but play fine on my computer.

I have the same problem with files produced by Sony camera. Does anyone know, if latest firmware 1.04.17 solved the problem?

nope, you have to use tmuxer to remove the delay before using on live hub (or wd tv live plus )

Same issue here. I’ve got the latest firmware update installed, but I still get a 5 second video then the video freezes and the audio is played, then the audio and video are in sync.

I’ve got a synology NAS and 1gb/s network.

When will this issue be resolved by WD.

Also it takes quite a long time before the video start, so when viewing a large number of small videos then you end looking at black screen for quite some time.

With regards.

Koen

Hi,

Yes… Same story here. All m2ts files from my Sony HD camcorder start with video only, then video freezes and audio starts. Then both continue in sync,

And I bought this box to view my camcorder files in an easy way :frowning: :frowning: :frowning:

WD: Hopefully you fix this fast in one of your upcoming firmware updates!

Cheers!

Keep your fingers crossed.   Supposedly Tuesday’s release for the WDTV Live fixed this, so it’ll probably be on the Hub soon…