Fastest way to extract frames using ffmpeg

ffmpegvideo

Hi I need to extract frames from videos using ffmpeg.. Is there a faster way to do it than this:

ffmpeg -i file.mpg -r 1/1 $filename%03d.jpg

Best Answer

If the JPEG encoding step is too performance intensive, you could always store the frames uncompressed as BMP images:

ffmpeg -i file.mpg -r 1/1 $filename%03d.bmp

This also has the advantage of not incurring more quality loss through quantization by transcoding to JPEG. (PNG is also lossless but tends to take much longer than JPEG to encode.)

ffprobe

ffprobe -v error -select_streams v:0 -count_packets -show_entries stream=nb_read_packets -of csv=p=0 input.mp4

This actually counts packets instead of frames but it is much faster. Result should be the same. If you want to verify by counting frames change -count_packets to -count_frames and nb_read_packets to nb_read_frames.

What the ffprobe options mean

-v error This hides "info" output (version info, etc) which makes parsing easier (but makes it harder if you ask for help since it hides important info).
-count_frames Count the number of packets per stream and report it in the corresponding stream section.
-select_streams v:0 Select only the first video stream.
-show_entries stream=nb_read_packets Show only the entry for nb_read_frames.
-of csv=p=0 sets the output formatting. In this case it hides the descriptions and only shows the value. See FFprobe Writers for info on other formats including JSON.

Only counting keyframes

See Checking keyframe interval?

MP4 Edit List

The presence of an edit list in MP4/M4V/M4A/MOV can affect your frame count.

Also see

mediainfo

The well known mediainfo tool can output the number of frames:

mediainfo --Output="Video;%FrameCount%" input.avi

MP4Box

For MP4/M4V/M4A files.

MP4Box from gpac can show the number of frames:

MP4Box -info input.mp4

Refer to the Media Info line in the output for the video stream in question:

Media Info: Language "Undetermined (und)" - Type "vide:avc1" - 2525 samples

In this example the video stream has 2525 frames.

boxdumper

For MP4/M4V/M4A/MOV files.

boxdumper is a simple tool from l-smash. It will output a large amount of information. Under the stsz sample size box section refer to sample_count for the number of frames. In this example the input has 1900 video frames:

boxdumper input.mp4
  ...
  [stsz: Sample Size Box]
    position = 342641
    size = 7620
    version = 0
    flags = 0x000000
    sample_size = 0 (variable)
    sample_count = 1900

Be aware that a file may have more than one stsz atom.

Rotating videos with FFmpeg

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.