Welcome to OStack Knowledge Sharing Community for programmer and developer-Open, Learning and Share
Welcome To Ask or Share your Answers For Others

Categories

0 votes
673 views
in Technique[技术] by (71.8m points)

rotation - Rotating videos with FFmpeg

I have been trying to figure out how to rotate videos with FFmpeg. I am working with iPhone videos taken in portrait mode. I know how to determine the current degrees of rotation using MediaInfo (excellent library, btw) but I'm stuck on FFmpeg now.

From what I've read, what you need to use is a vfilter option. According to what I see, it should look like this:

ffmpeg -vfilters "rotate=90" -i input.mp4 output.mp4

However, I can't get this to work. First, -vfilters doesn't exist anymore, it's now just -vf. Second, I get this error:

No such filter: 'rotate'
Error opening filters!

As far as I know, I have an all-options-on build of FFmpeg. Running ffmpeg -filters shows this:

Filters:
anull            Pass the source unchanged to the output.
aspect           Set the frame aspect ratio.
crop             Crop the input video to x:y:width:height.
fifo             Buffer input images and send them when they are requested.
format           Convert the input video to one of the specified pixel formats.
hflip            Horizontally flip the input video.
noformat         Force libavfilter not to use any of the specified pixel formats
 for the input to the next filter.
null             Pass the source unchanged to the output.
pad              Pad input image to width:height[:x:y[:color]] (default x and y:
 0, default color: black).
pixdesctest      Test pixel format definitions.
pixelaspect      Set the pixel aspect ratio.
scale            Scale the input video to width:height size and/or convert the i
mage format.
slicify          Pass the images of input video on to next video filter as multi
ple slices.
unsharp          Sharpen or blur the input video.
vflip            Flip the input video vertically.
buffer           Buffer video frames, and make them accessible to the filterchai
n.
color            Provide an uniformly colored input, syntax is: [color[:size[:ra
te]]]
nullsrc          Null video source, never return images.
nullsink         Do absolutely nothing with the input video.

Having the options for vflip and hflip are great and all, but they just won't get me where I need to go. I need to the ability to rotate videos 90 degrees at the very least. 270 degrees would be an excellent option to have as well. Where have the rotate options gone?

Question&Answers:os

与恶龙缠斗过久,自身亦成为恶龙;凝视深渊过久,深渊将回以凝视…
Welcome To Ask or Share your Answers For Others

1 Answer

0 votes
by (71.8m points)

Rotate 90 clockwise:

ffmpeg -i in.mov -vf "transpose=1" out.mov

For the transpose parameter you can pass:

0 = 90CounterCLockwise and Vertical Flip (default)
1 = 90Clockwise
2 = 90CounterClockwise
3 = 90Clockwise and Vertical Flip

Use -vf "transpose=2,transpose=2" for 180 degrees.

Make sure you use a recent ffmpeg version from here (a static build will work fine).

Note that this will re-encode the audio and video parts. You can usually copy the audio without touching it, by using -c:a copy. To change the video quality, set the bitrate (for example with -b:v 1M) or have a look at the H.264 encoding guide if you want VBR options.

A solution is also to use this convenience script.


与恶龙缠斗过久,自身亦成为恶龙;凝视深渊过久,深渊将回以凝视…
Welcome to OStack Knowledge Sharing Community for programmer and developer-Open, Learning and Share
Click Here to Ask a Question

...