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2

Hope this explanation is what you're looking for: When you transcode to an encoding such as H.264 (MPEG-4 part 10) you necessarily also resample the video, that's part of H.264 compression technique. Nontheless, I doubt if this is the reason you experience a timing gap since the resampling doesn't necessarily influence the clock rate of the media. So, I ...


3

This is possible but will require scripting. ffprobe will be used to determine the duration of the input, then the countdown and background box will be created by the drawtext filter. A 30 second input will start from 30 and count down to 0. Example: input=input.mp4 duration=$(ffprobe -loglevel error -show_entries format=duration -of default=nw=1:nk=1 ...


3

Use drawbox for the box, and drawtext for the text. ffmpeg -i input.mp4 -vf \ "format=yuv444p, \ drawbox=y=ih/PHI:color=black@0.4:width=iw:height=48:t=max, \ drawtext=fontfile=OpenSans-Regular.ttf:text='Title of this Video':fontcolor=white:fontsize=24:x=(w-tw)/2:y=(h/PHI)+th, \ format=yuv420p" \ -c:v libx264 -c:a copy -movflags +faststart output.mp4 ...


2

First you need to extract the frame that you wish to freeze. This is easy: avconv -i test.webm -vf "select='eq(n,1)'" out.jpeg Then you want to put that frame for the appropriate time interval. avconv -i test.webm -loop 1 -i out.jpeg -an \ -filter_complex "[1:v]trim=start=0:end=5[ol];[0:v]setpts=125+PTS[nv];[nv][ol]overlay=eof_action=pass[final]" \ -map ...


3

Your current method using the concat demuxer while stream copying is probably the fastest (I'm just counting the ffmpeg time and not any time you take to enter the additional commands). Unfortunately, you have to perform several steps, but the advantage is that your non-filtered segments are not being re-encoded which preserves quality and results in fast ...


2

Using the latest ffmpeg General users should always use ffmpeg from the current git master branch (the latest code available): When encountering an issue the first thing to do is check to see if you are using a build from git master. It is considered stable. It will have more bug fixes and features. FFmpeg development is very active. If you want to get ...


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As I'm working on the exact same challenge, I'm currently thinking of abusing the ffmpeg vidstabtransform filter with a generated trf file. But I have not worked out the details yet. Info on the trf file format.


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Split using "-f segment -segment_time 10" and end with "360a-a%03d.mp4". Then create a text file with one entry on each line like "file '360a-a001.mp4", interleaving the entries in the correct order. Then join using -f concat -i text.txt and also with -flags +genpts -async 1 The "-flags +genpts -async 1" is necessary to ensure that the concatenated audio ...


0

Both avconv and ffmpeg suffer from the poorly chosen defaults for each container and codec. Therefore you should not simply give the command in the format as you have presented, but also tell it what to do. I use avconv, but if you are still using ffmpeg then the format is rather similar, so you should be able to follow. You will need to specify the audio ...


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I have already changed to avconv, so i apologise if the answer may be a little different in the classic ffmpeg, but i believe that not much difference should be there. You can have a moving crop if you can create some sort of formula between the frame number and the position of the crop; but there are no analytic tools available to do that. This means that ...


-1

After Effects should be able to do this. It allows you to track a selected object as it moves around the screen. Set the speaker's head as the selected object. Have the virtual "camera" track him as he moves around. It will appear as though the original camera was tracking him perfectly as he moved. You can then apply a stationary mask around that area ...



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