Audio Only Output Recoding - why?

MrVideo

Active member
MPEG-2/AC3/MPEG audio

When I tell VRD 619 to only output the audio, it says that it is recoding. Recoding what, as it is only supposed to be saving the audio as is. The two file names are .ac3 and .mpa, but it is taking longer as recoding of some type is taking place and is indicated as such on the dialog box.
 

Dan203

Senior Developer
Staff member
Check the files in MediaInfo. If they are actually AC3 and MP2 then it can't possibly be recoding. The way the code is setup all output types either have to be their original format or, if they are recoded, they are all recoded to the same format. There is no way to recode just 1 of the streams or to recode the individual streams to different formats.

Edit: How much longer is it taking? Perhaps something is causing the video to recode. Even though you're outputting audio only, the video is still processed slightly. If something was messed up there then it might trigger the video to be recoded which would slow things down significantly.

Dan
 

MrVideo

Active member
It is taking ~9 minutes for a 16 GB file. I did look at the files after it was done and they were as expected, i.e., no change in audio type.

The video is clean as it was put through eac3to first in order to make the AC3 stream from three of the original audio streams. The leftover audio stream is a stereo mixdown.

Is it because I did a 925 ms correction on the audio. The MPEG audio had an issue, so I needed to correct it and will remux the corrected audio.

BTW, when you run audio only, there is no warning that the audio files are being overwritten. It just blindly deletes what is there.
 

Dan203

Senior Developer
Staff member
That seems about right. The audio only option still has to demux all the video frames, they are simply tossed out before they get to the muxer. Outputting to audio only should take slightly less time then QSFing that same file.

The overwrite thing has always been true of ES output. The Save dialog can only compare one file name. With single audio output ti can check for an overwrite and prompt, but with multiple audio streams it only checks the first stream and the file it will create. I might be able to add some code to overwrite the default check and check all audio streams, but it's low priority.

Dan
 

MrVideo

Active member
That seems about right. The audio only option still has to demux all the video frames, they are simply tossed out before they get to the muxer. Outputting to audio only should take slightly less time then QSFing that same file.
Any idea as to why it says that it is recoding, even though it really isn't?

The overwrite thing has always been true of ES output. The Save dialog can only compare one file name. With single audio output ti can check for an overwrite and prompt, but with multiple audio streams it only checks the first stream and the file it will create. I might be able to add some code to overwrite the default check and check all audio streams, but it's low priority.
Then should it not complain, as both audio streams are there when I rerun the job (as I narrow down the audio adjust value)? Yet, both are blindly rewritten.
 

Dan203

Senior Developer
Staff member
Any idea as to why it says that it is recoding, even though it really isn't?
No. Does the Save dialog say that it needs to be recoded? Or just the output dialog?

Then should it not complain, as both audio streams are there when I rerun the job (as I narrow down the audio adjust value)? Yet, both are blindly rewritten.
When you save it should ask you for a file name with an extension that corresponds to the first audio stream. If you pick one that exists then it should complain just like it would with any other file.

Dan
 

MrVideo

Active member
No. Does the Save dialog say that it needs to be recoded? Or just the output dialog?
Damn good question. For sure the output dialog box does. Do not remember if the Save dialog did. Can't check now, with this particular job, but I can try and duplicate the situation with another file that has the same layout.

When you save it should ask you for a file name with an extension that corresponds to the first audio stream. If you pick one that exists then it should complain just like it would with any other file.
Ah, there in lies the loophole. When I do elementary stream outputs, I remove the extension as I ran into a problem having an extension. Mostly when leaving the ".ts" as part of the original file, as VRD didn't remove the ".ts" and just appended the other extensions. So, I leave off the extension and let VRD add the extension that it needs.

Also, I don't remember seeing anything asking for a file name that corresponds to the first audio stream.
 
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