Using the DGAVCdec audio delay value when muxing with ffmpeg

[johnnyquid]

How do I use the audio delay value reported from DGAVCdec when
muxing converted files back using ffmpeg?

Assume that I demux and index a M2TS file using DGAVCdec to create
a ac3 file. The audio delay reported in the filename created by
DGAVCdec is -66 ms.

Audio file is:
video.dga PID 1100 3_2ch 48KHz 448Kbps DELAY -66ms.ac3

I then convert the video stream in the M2TS file into a m2v file
(video.m2v) using HCenc. I then rename the ac3 file to video.ac3.
I now have two files that I want to maintain the original
audio/video synch when muxing using ffmpeg.

Is the correct ffmpeg command line the following?

ffmpeg -i video.ac3 -i video.m2v -itsoffset 00:00:00.066 -vcodec
copy -acodec copy -target ntsc-dvd video.mpg

Note that offset is applied to video m2v file and the offset is
the opposite of the value in the filename generated by DGAVCdec.
As I understand it, the value (-66) reported by DGAVCdec is the
correction needed to be input into virtualdub's audio skew
correction box. For this input, a negative value would be used if
the audio is occurring to late.

If there is a better way to mux the files using free command line tools, let me know.

Thanks,

[hydra3333]

Will ImagoMPEG do it ?

[johnnyquid]

I think I had the sign incorrect but it was only noticable with larger audio delays. Not changing the sign appears to be correct. For example the following seems to give the correct audio/video synch. I also previously had itsoffset in the wrong place. It needed to be after the video file and before the audio file.

ffmpeg.exe -i "c:\temp\temp\video.0001.m2v" -itsoffset -00:00:00.776 -i "c:\temp\temp\video.0001 PID 014 3_2ch 384Kbps DELAY -776ms.ac3" -vcodec copy -acodec copy -target ntsc-dvd -y "e:\temp\output\video.0001.mpg"