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For a one hour dash cam video in normal speed, is it possible to create a smooth timelapse video from it?
Most tutorials online I found about "timelapse + ffmpeg" are with static jpeg files combined into a timelapse video. These often result jiggle between frames, are the any specific parameters which would make the video looking very smooth & stable?
Should I just setpts=0.5*PTS for the trick? Any must-have or little-known tricks?
Update: this question is asking for specific programmable ffmpeg parameters.
Yes, that's the way specified in the ffmpeg wiki: How to speed up / slow down a video.
ffmpeg -i input.mkv -filter:v "setpts=0.5*PTS" output.mkv
setpts also supports expressions if you feel creative and want to speed up/ slow down based on a curve rather than a constant value.
Eg: -filter:v "setpts=gauss(T/100)*PTS"
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Learning to speed up and slow down video using the ffmpeg setpts filter, but I am struggling to get a simple expression to work.
ffmpeg -i .\F5-ff.mp4 -filter:v "setpts=0.25*PTS" ff-test3.mp4
I get the output file, but it is not any faster than the original.
I'm sorry if this has already been addressed. Most related post I've found were trouble shooting more complex operations past this step. Im working in a powershell terminal fyi.
Just realized what was happening...I was looking at the total length of the video, but closer look showed that video portion was actually faster, but total length of file remained unchanged because audio track had not been shortened.
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i use to convert videos by ffmpeg with h264_nvenc codec, currently i noticed that nvidia-smi command shows GPU utilization is less that 20 percent.
how could i utilize more GPU and fasten the process?
You can’t. Nvenc is not gpgpu. It is deticated silicon for accelerating some steps of the video encoding process. The bottle neck is in this component. Not in the vector units.
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I was exploring the ffmpeg video conversion. Wanted to know what will be the hardware requirements and the time taken to convert a 5gb video file
typically it depends on how much compression you want. If you want high compression and good quality, it takes forever. But it is also different between video codecs (and to a small extent, audio codecs, as well), some are faster, some are slower.
Hardware requirements are basically "any cpu" (you might get some speedup with graphics card GPU but ffmpeg doesn't use them heavily/typically yet). But with stronger hardware, it will convert "faster" as it were.
FFmpeg can almost run on everything.
You can see this:
https://ffmpeg.org/pipermail/ffmpeg-user/2011-March/000094.html
I don't think there is a standard runtime of coverting 5gb video file. The time may depend on your hardware, the input/output video codec, resolution, format,etc.
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I have a video of 120MB.I need to reduce its size to 20 MB without changing its quality.Is there any direct ffmpeg command which i can run?
I know the commands to reduce video size between specific time intervals and for resolution.Is there any way ffmpeg can reduce the size in MB?
I need to reduce its size [..] without changing its quality.
That is generally not possible.
I have a video of 120MB. I need to reduce its size to 20 MB
Welcome to video coding (and audio coding). Tell us something about the input file. Run:
ffprobe input
This will tell us how the file is currently coded. Then, let's work on re-encoding it. First, I'm assuming you don't want to change resolution/framerate, so we'll keep that the same. Second, let's select a video codec/encoder. Depending on the options built into your ffmpeg binary, the typical options are H.264 (x264), VP9 (libvpx) or HEVC (x265).
There's various ways to encode videos (CRF 2-pass, VBR 2-pass), so which do you choose? Since you want a video of a particular size, you want VBR (CRF is if you want it to be of a particular quality and don't care about size). How do you calculate the bitrate? ffprobe tells you the duration of the video (in seconds), and target bitrate is calculated as:
target_rate_bits_per_second = target_size_bytes * 8 / duration_seconds
And then you use this bitrate as value for the -b:v option in each variable bitrate command I just linked to.
[edit] Assuming you have audio also, distribute the available bits between video and audio streams so that the total bitrate sum gives 20MB. Also assume a little bit of container overhead. [/edit]
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I have imported PAL DV. When trying this
ffmpeg -i my_video.dv output.mp4
I get interlacing issues.. So I need to deinterlace the input somehow...
This did the trick!
ffmpeg -i my_video.dv -vf yadif output.mp4