Machine Gun Sound ??

[rorkin]

Been getting a machine gun sound every few seconds on Baltamore ABC. Dish Transmission
I have experienced this on several other channels.. Whats up with this ??

HR20 -700 with AM 21 and external Hard drive...
Hdmi..

[LameLefty]

This is an MPEG4 audio synchronization issue, well documented around this forum. It's commonly called the "Brrrp!" sound or the "Woody Woodpecker effect." Unfortunately, it's not something on your end that can be fixed with software or receivers - it seems to be entirely an issue with Directv and their encoding/transcoding process. It's generally worst on local HD channels, though I've heard small examples on it on CNN HD and NFL HD lately too.

[tzphotos.com]

I have both OTA and DirecTV locals. Our CBS station in Chicago ( WBBM - TV ) does this about 4 or five times during a 1 hour program.

I happened to record a program from both the OTA and DirecTV HD Local.

The OTA ( 2.1 ) : The sound just cut out.
The HD Local ( 2 ): The sound did the machine gun sound.

So it may be your local stations problem. It just manifests itself a little different with MPEG 4 vs MPEG 2.

I know it's not DirecTV because it occurred at exactly the same time, because I compared the two recordings.

Hope this helps,

[1948GG]

I have both OTA and DirecTV locals. Our CBS station in Chicago ( WBBM - TV ) does this about 4 or five times during a 1 hour program.

I happened to record a program from both the OTA and DirecTV HD Local.

The OTA ( 2.1 ) : The sound just cut out.
The HD Local ( 2 ): The sound did the machine gun sound.

So it may be your local stations problem. It just manifests itself a little different with MPEG 4 vs MPEG 2.

I know it's not DirecTV because it occurred at exactly the same time, because I compared the two recordings.

Hope this helps,

You are maybe (might have missed someone before) to document that indeed, the OTA transmission AND the DirecTV had something like 'thing A resulted in thing B'.

Others earlier had come up with it was something to do with the Dolby 'wacking' the encoders. Your capture seems to maybe help confirm that indeed, it's something with the audio stream (burping?) that the Mpeg4 encoders simply 'do not like'. Somewhere, someone had come up with the idea that the Dolby bit rate was changing, I don't suppose your Dolby decoder (receiver or other) has a bit rate display, and you can take a look at those recording and see if something in that area 'jumps'?

I know we're all grasping at straws here. But I spent a goodly amount of time designing Mpeg2 encoders 'back in the day' (late 80's early 90's), and it particularly grates on me.

Thanks! :D