Ticket #1717 (open defect)
Concat filter can not join individual images
| Reported by: | chinshou | Owned by: | |
|---|---|---|---|
| Priority: | minor | Component: | avfilter |
| Version: | git-master | Keywords: | |
| Cc: | Blocked By: | ||
| Blocking: | Reproduced by developer: | yes | |
| Analyzed by developer: | yes |
Description
using latest ffmepg build from http://ffmpeg.zeranoe.com/builds/win32/static/ffmpeg-20120903-git-5d55830-win32-static.7z
execute following command
ffmpeg -i a1.jpg -i a2.jpg -i a3.jpg -filter_complex "[0:0] [1:0] [2:0] concat=n=3:v=1:a=0" join.mp4
to join three jpeg files to one video, But the generated mp4 file only contain two frames.
ffmpeg -i join.mp4 test%d.jpg
only output test1.jpg and test2.jpg
best regards
Change History
comment:1 Changed 9 months ago by Cigaes
- Status changed from new to open
- Reproduced by developer set
- Summary changed from Concat filter can not join more than two video files to Concat filter can not join individual images
- Priority changed from normal to minor
- Version changed from unspecified to git-master
- Analyzed by developer set
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This is a timestamp problem: concat uses the mean inter-frame interval as the duration of the last frame to separate the segments. If a segment is made of a single video frame and no audio, then there is no inter-frame interval, and the next segment starts at the same time. This will then cause frame dropping depending on the vsync algorithm.
The filter works correctly (AFAIK) if all the segments have more than one frame or have audio.
Temporary workaround: use setpts to shift the time of each segment after a single image, or add dummy audio and discard it.
The problem can be properly fixed when a duration field will be added to filtered frames; this is work in progress.