MP4 Audio Bad

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Joined: Thu Nov 06, 2014 11:58 pm

MP4 Audio Bad

Post by Resadme » Fri Nov 27, 2020 3:56 am

The field of video formats, codecs etc. is a minefield and I am very ignorant about the subject! My UMS set-up is not able to play MP4 files well – not sure if increasing the buffer or other changes might improve the output. I am “getting on in years” so I find it more challenging to do the research required to understand which UMS parameters to modify, so I need your help to resolve my audio problem (and a minor issue with video if possible)!

In the past, I successfully used UMS to view video files on an ethernet-connected Sony Bravia KDL-40Z5500U. My only issue was that a Dolby Digital ‘watermark’ was shown continuously during the playing of videos – not a big problem but annoying (this ‘watermark’ was not on the videos when viewed directly).

Recently when modifying my computer setup I thought it would be sensible to update UMS to see if the DD watermark would disappear. I performed a ‘clean install’ of UMS. Foolishly I did not keep a record of the UMS parameters that I modified when I went through the set up several years ago. With this new installation, the MP4 files that I want to view on the TV run poorly; the video is OK although there is minor flickering (more of a ‘shimmer) – which is not seen when videos viewed directly on the PC – and, an improvement, no ‘DD watermark’ is displayed! But the main problem is the audio which breaks up very badly.

I viewed the transcoded files generated by various engines and the best, albeit still producing very poor audio, was produced by VLC so I have moved that to the top of the list of Video File Engines. That is the only modification I have made to the default configuration.

I am using Cyberlink PowerDirector 13 to produce video projects containing photos and video clips. I saved the projects using 1920 x 1080/24p (16Mbps) H264 AVC as mp4 files.

I used version 9.8.2 of UMS

Processor: Intel(R) Core(TM) i7-4770 CPU @ 3.40GHz; Memory: 16GB; Graphics: NVIDIA GeForce GTX 770; Hard Disk on which OS & Programmes saved: SSD, SanDisk 256Gb; Hard Disk on which photos and video saved: 2TB;
Trace Logs
(323.12 KiB) Downloaded 49 times
OS: Windows 10, 64bit

I have a Sonos Playbar plus 2 x Sonos Ones as rear speakers providing sound from the TV. I should like the sound from videos to play on all speakers; at present the audio from MP4 videos – albeit poor – is heard on all speakers.

The attached zip file of Trace Logs was generated when playing a 30 minute video. The audio was good for about 6 min then broke up, followed by a recovery but deteriorated after ~7min; the video quality was acceptable but with the minor flickering mentioned above. Playback was stopped at 10min.

Any advice gratefully received!

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