CODEWITHSUNDEEP
ffmpegkeyframe
rabotalius
rabotalius

Reputation: 1568

Checking keyframe interval?

How can I check keyframe interval of a video file?

all I can see in ffmpeg output is:

  Metadata:
    metadatacreator : Yet Another Metadata Injector for FLV - Version 1.8
    hasKeyframes    : true
    hasVideo        : true
    hasAudio        : true
    hasMetadata     : true
    canSeekToEnd    : true
    datasize        : 256600272
    videosize       : 210054362
    audiosize       : 45214634
    lasttimestamp   : 5347
    lastkeyframetimestamp: 5347
    lastkeyframelocation: 256649267
  Duration: 01:29:07.24, start: 0.040000, bitrate: 383 kb/s
    Stream #0:0: Video: h264 (High), yuv420p, 720x304 [SAR 1:1 DAR 45:19], 312 kb/s, 25 tbr, 1k tbn, 50 tbc
    Stream #0:1: Audio: mp3, 44100 Hz, mono, s16p, 64 kb/s

Upvotes: 43

Views: 52319

Answers (3)

atyachin
atyachin

Reputation: 1161

Here's a command to get the keyframe interval of an input file/stream:

probtime=10 && ffprobe -hide_banner -of compact=p=0:nk=1 -select_streams v:0 -count_frames -show_entries stream=nb_read_frames -skip_frame nokey -v 0 -read_intervals "%+$probtime" -i INPUT.mp4 | awk -v probtime="$probtime" '{print probtime/$1}'

probtime - in seconds

result - keyframe interval (i.e. a keyframe is set every X seconds)

Upvotes: 1

llogan
llogan

Reputation: 134173

You can display the timestamp for each frame with ffprobe with awk to only output key frame info. Works in Linux and macOS.

ffprobe -loglevel error -select_streams v:0 -show_entries packet=pts_time,flags -of csv=print_section=0 input.mp4 | awk -F',' '/K/ {print $1}'

Or a slower method that works on any OS and does not require awk or similar additional processing tools:

ffprobe -loglevel error -skip_frame nokey -select_streams v:0 -show_entries frame=pkt_pts_time -of csv=print_section=0 input.mp4

Results:

0.000000
2.502000
3.795000
6.131000
10.344000
12.554000
16.266000
17.559000
...

See the ffprobe documentation for more info.

Upvotes: 92

Uday Shankar
Uday Shankar

Reputation: 39

The following command will give you the offsets of all key Frames in the Video

ffprobe -show_frames -select_streams v:0 \
        -print_format csv Video.mov 2> /dev/null |
stdbuf -oL cut -d ',' -f4 |
grep -n 1 |
stdbuf -oL cut -d ':' -f1

Note that the command might respond a little late. Have patience :-)

The ffprobe command gives you the frame level details in CSV format. Rest is a smart combination of cut and grep commands.

cut -d ',' -f4

filters the fourth column - this refers to the 'key_frame' flag. 

grep -n 1

filters the key-frames only, and shows their line numbers in the CSV feed.

The 

stdbuf -oL

with the cut command manipulates the buffer of the cut command.

Upvotes: 3

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