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IDProjectCategoryView StatusLast Update
0007312ardourbugspublic2021-03-27 22:25
Reportergostevehoward Assigned To 
Status newResolutionopen 
OSUbuntuOS Version16.10 
Product Version5.8 
Summary0007312: Audio export fails with negative -itsoffset for video track -- no video track in output
DescriptionI have a 0000009:0000010 min recording session in Ardour and a corresponding MP4 video, which starts slightly before the audio session. I import the video and drag the video track backwards to get it to line up with audio. I then only want to export a couple minutes starting about 8 min into the session, so I set the "start" and "end" markers. Everything looks good in Ardour, audio export works perfectly, so I go to video export with the mp4/h264 preset. I check the debug option so it prints the ffmpeg command:

/opt/Ardour-5.8.0/bin/ffmpeg_harvid -itsoffset -471.185 -i <path>.MP4 -i <path>/export/vtl_mysession.wav -acodec aac -strict -2 -t 159.351 -vcodec libx264 -metadata comment="Created with Ardour" -map 0:0 -map 1:0 -y <path>/export/export.mp4

The resulting export.mp4 file has no video track, just audio. I tried replacing the -itsoffset option with -ss (seek), running the following by hand (I manually copied the vtl_mysession.wav intermediate file beforehand):

/opt/Ardour-5.8.0/bin/ffmpeg_harvid -ss 471.185 -i <path>.MP4 -i <path>/export/vtl_mysession2.wav -acodec aac -strict
 -2 -t 159.351 -vcodec libx264 -metadata comment="Created with Ardour" -map 0:0 -map 1:0 -y <path>/export/export2_harvid.mp4

This seems to work perfectly.

Let me know if I can provide more info that will help. It's my first time reporting an Ardour bug so I don't know the ropes. And of course thank you so much for this wonderful wonderful piece of software.
TagsNo tags attached.



2021-03-27 22:25

reporter   ~0025649

Same here... The `ss` option didn't sync up properly for me, I had to add 3 to get to where I needed to be. I guess from now on, I'll start Ardour recording before I start the video recording, so I don't have to move the video back. It's messy but it should work. Of course, not everyone will have my fairly trivial use case of filming guitar solos at home. Strange though, as negative `-itsoffset` values should be supported.

Issue History

Date Modified Username Field Change
2017-04-10 00:55 gostevehoward New Issue
2021-03-27 22:25 antgel Note Added: 0025649