Problem with Audio distortion on Play back of DVD video files

Hi,

I finally got around to testing the DVD file playback on the WD TV Live Hub Media player.

What I did was to create a simple project which contained a menu with two short music related video titles. The video editor I used let me create the DVD files on my computer’s hard drive.

After creating the files I created a Video DVD (i.e. burned a video DVD using Nero burning ROM) and tried playing the DVD on my DVD player with everything playing and sounding as per my expectations.

I then took the same set of files and Transfered them over to the WD TV Live Hub’s hard drive. I then browsed over to the directory containing the DVD folders (i.e. AUDIO_TS and VIDEO_TS) and pushed OK on the remote. I was delighted to see the menu come up, just like it did with the DVD on my DVD player. I was able to select a title and play it in the same way etc …great!..BUT, unfortunately I discovered an issue with the audio. Essentially the audio sounded like it was being overdriven somewhere in the audio chain…i.e. it was distorted. So it would seem that there is a problem with audio playback distortion using the WD TV Live Hub. I’m guessing it is an issue with how the media player manages audio levels in it’s audio playback chain…There is some clipping happening somewhere in that playback chain (i.e. cascaded elements etc.).  I would be happy to upload the files in question to whomever wished to reproduce the problem and debug the issue.

Has anybody else observed this issue and found a work around?

Thank-you

Charles

I haven’t run into that; but all of my DVDs are commercially made.   I haven’t tried any of the ones I created a long time ago.

What audio format did you use for the audio tracks?

Hi Tony,

I checked out some of the individual *.VOB files using MediaInfo and found them to be using the AC-3 audio format i.e. the Dolby format…note that I have other non-DVD related video files (i.e. *.m2ts files) with AC-3 format that play correctly on the Hub (i.e. with no distortion) so I’m not sure why this may or may not be an issue etc…

I have a few experiment ideas to try…e.g. I will try lowering the audio level in the video editor that creates the files. Another experiment might be to try just using PCM (i.e. or LPCM i.e. Linear PCM) although it is not an attractive work around due to the larger files sizes that would be generated.

Thanks,

Charles

I’m now having the same problem on some files, after the firmware upgrade.  It’s happened on one .iso and one .avi so far. I haven’t checked everything, but most others seem OK.

The distortion and volume is very pronounced,  as in very loud. Not sure if the firmware changed any settings.

Hey!

If I were to try to re-create your scenario, what software would I need?

I’ve currently got my Live Hub Hooked up to my surround sound receiver via HDMI. I’ve set the audio to “digital pass-thru”… My receiver will indicated “Dolby Digital” when playing back 5.1 dolby encoded DVD’s or “DTS” for 5.1 dts encoded DVD’s.

When playing back .M2TS files, my receiver will display “TrueHD” when playing back “TrueHD” encoded material and “DTS” when playing back “DTS HD” encoded material. However, the player displays “DTSMA” or “DTSHD” as though it recognizes the lossless material – it just doesn’t pass it through.

Most of my AC3 labeled discs are 2-channel 16-48 encoded. Although I have seen some labeled AC3 that are mult-channel. Is your AC3 source 2-channel 16-48 encoded?

Hi TabCursor,

I used PowerDirector 9.0 to create the DVD ready files. I also used PowerDirector 9.0 to create *.m2ts files of the same material (i.e. same originating video clips from my JVC camera). Both the DVD files and the *.m2ts files produced by PowerDirector 9.0 contained 2-channel (i.e. Stereo) 256 kbps AC-3 encoded audio.

Note that the *.m2ts file’s audio plays without any distortion (i.e. they’re fine)

The DVD files play with a fair degree of distortion (i.e. same sound of an intermediation audio stage being overdriven).

Note that the audio levels (i.e. volume) sound to be about the same between the DVD and *.m2ts files. These are both using AC-3 with 48 ksamples/s

I have since tried playing some old DVD files (i.e. *.VOB) I’d produced using Nero 9 and Nero 7 software (i.e. Nero Vision) which produced DVD files with LPCM audio on them. These file’s audio playback cleanly. I don’t believe their audio volume is as loud so I’m not convinced this proves anything regarding the problem i.e. whether the distortion is somehow related to the audio format etc…Based on what I’ve observed I have to suspect that for whatever reason there is some kind of audio gain/overdrive issue when the Hub plays *.VOB files with higher signal levels. I will try and do an experiment where I lower the volume of the audio on the *.VOB files and see if they play without distortion.

Another experiment is suggested in one of the replies above…i.e. try reverting back to the previous version of firmware i.e. *.16 and observe if the problem is still there. Note that I only started experimenting with DVD files this morning after updating to the new firmware.

Charles

Hey!

I have PowerDirector around here somewhere…not sure it’s version Nine. I also have a JVC camera that captures two-channel audio. So I have lots of examples to choose from. I’ll try throwing some of my JVC vids at it and see if I can re-create your situation. I do remember there are some issues with my JVC when recording in widescreen vs. standard. I don’t think that’s related to audio, however.

Most commercial DVDs are higher bitrates – 384K and up to 640K. Having said that, I did try playing back Youssou N’Dours “Live In London” DVD. The WD HUB displayed “AC3” onscreen, but my receiver “DDigital”… I’ll get around to my JVC and let you know.

Sounds like you’re enjoying the player – even with the glitches.

By the way, which soundcard are you using on your encoding PC for PowerDirector?

I tried a quick experiment today.

I took the DVD video project that was producing the overdriven audio and lowered it’s internal volume to 75% (i.e. according to Nero 9’s nero vision editor) and tried playing the new files thru the Hub…played without distortion…i.e. so it would seem the Hub’s audio chain is more sensitive to higher signal (i.e. since the files did not sound over driven when playing the burned files on my DVD player etc.).

i.e. so problem is not related to format since the new project with the volume lowered to 75% was also in the AC-3 format.

Charles