Rendered MP4 Files - Video but no audio in Quicktime on different PC

[pauldsc]

I have a frustrating problem on a particular PC with no sound when playing certain rendered mp4 and mov files.

I create and render MP4 files on a video editing PC (“PC1”) which is standalone (not internet connected) in a log cabin in my garden and runs Sony Vegas 7 Pro. These files are rendered for upload to Vimeo or Youtube using a custom Mainconcept AVC/AAC rendering template at Vimeo recommended compression settings. I test these in Quicktime and VLC and they run fine (video and audio!). I copy them to USB stick.

When I load these MP4 files from the USB stick into PC2 in the house for upload to Vimeo they have no audio in Quicktime but the video is just fine (VLC is OK for video and audio – but strangely only plays audio when the audio device is set to mono!!??). MP4 files uploaded to Vimeo and Youtube have no sound on PC2 but the audio apparently plays OK on other PCs accessing the internet. I am now running the same version of Quicktime on both PCs (v 7.7.1) and the same version of VLC (1.1.11). I have the latest version of Flash Player (11.0.1.152) installed on PC2. I have tried rendering as MOV and the results are the same (OK in VLC but won’t play audio in Quicktime on PC2 and files uploaded to Vimeo have no sound when played back on PC2).

MediaInfo reports on affected files look OK with regard to AAC LC audio (GSpot returns similar info). (You will note I live in “PAL” land which will explain video frame rate etc.):


File size : 6.72 MiB
Duration : 24s 683ms
Overall bit rate mode : Variable
Overall bit rate : 2 282 Kbps
Encoded date : UTC 2011-11-03 16:56:15
Tagged date : UTC 2011-11-03 16:56:15

Video
ID : 2
Format : AVC
Format/Info : Advanced Video Codec
Format profile : Main@L3.1
Format settings, CABAC : Yes
Format settings, ReFrames : 2 frames
Format settings, GOP : M=3, N=24
Codec ID : avc1
Codec ID/Info : Advanced Video Coding
Duration : 24s 680ms
Bit rate mode : Variable
Bit rate : 1 958 Kbps
Maximum bit rate : 5 000 Kbps
Width : 768 pixels
Height : 576 pixels
Display aspect ratio : 4:3
Frame rate mode : Constant
Frame rate : 25.000 fps
Standard : NTSC
Color space : YUV
Chroma subsampling : 4:2:0
Bit depth : 8 bits
Scan type : Progressive
Bits/(Pixel*Frame) : 0.177
Stream size : 5.76 MiB (86%)
Language : English
Encoded date : UTC 2011-11-03 16:56:15
Tagged date : UTC 2011-11-03 16:56:15

Audio
ID : 1
Format : AAC
Format/Info : Advanced Audio Codec
Format profile : LC
Codec ID : 40
Duration : 24s 683ms
Bit rate mode : Constant
Bit rate : 320 Kbps
Channel(s) : 2 channels
Channel positions : Front: L R
Sampling rate : 44.1 KHz
Compression mode : Lossy
Stream size : 964 KiB (14%)
Language : English
Encoded date : UTC 2011-11-03 16:56:15
Tagged date : UTC 2011-11-03 16:56:15

I guess I need to find out why the files have no audio locally (in Quicktime on PC2 and in the Vimeo and Youtube players on PC2).

I have used the same workflow for 3 years without a problem. The render compressions settings I use in Vegas for Vimeo upload have not essentially changed in that time. Older rendered MP4s still play OK in Quicktime and VLC on PC1 and PC2 and have always uploaded to Vimeo without a problem. It is only the MP4 and MOV files created in the last week or so that have a problem.

I guess there have been several changes between the last working state and the current scenario including:

1. PC2 has changed from a W2K laptop to a Windows XP desktop machine;
2. There have been several patches and upgrades to both machines (XP service packs, upgrades to Quicktime, Flash Player) etc. etc.

In searching for a solution to this problem I have become aware of a possible problem with MP4 audio files for users of older Sony Vegas versions and Quicktime version 7.6.4 (see https://www.custcenter.com/app/answers/detail/a_id/4787/kw/4787/session/L3RpbWUvMTMyMD...Q0VpVDZnSWs%3D )

I guess I have assumed that this is not the cause of my problems for the following reasons:

The “problem” files were created when PC1 was using Quicktime 7.6 (before the issues that were introduced with Quicktime version 7.6.4 ).
PC2 was already using Quicktime 7.7.1 when these files were created. I understand that release 7.7.1 was not a problem for Sony Vegas and in any case there is no Sony video software running on PC2.
Yesterday I “upgraded” PC1 from Quicktime 7.6 to Quicktime 7.7.1 to see if MP4s and MOVs rendered in Sony Vegas would now run OK (with audio) in Quicktime on PC2. They do not. – there is no audio in Quicktime and no adio if the file is uploaded to Vimeo.

Before guessing that Quicktime might be to blame and taking Quicktime back to some previous version on one or both machines I thought I should ask for your advice (you can probably tell that I am not overly technical and find myself flailing around way beyond my comfort zone). Maybe there is some simple explanation for this (soundcard issue, missing codec).

I will freely admit that after several days of troubleshooting this problem my ability to think through this rationally may be somewhat compromised, so please feel free to challenge my assumptions and offer any advice or hints as to what I should try next.

Of course if more info is needed just let me know.

[DB83]

Well something appears screwed up. The video has PAL dimensions 768*576 yet reports to be NTSC ???.

You could upload a sample here and we could then have a better idea what is going on.