0

How do I extract I frames & DC coefficients from an MPEG-4 video?

Emil Vikström
  • 90,431
  • 16
  • 141
  • 175
Saddam
  • 1
  • 1

2 Answers2

2

If you want just the I frames the use ffmpeg to extract them. You can use the -vf select="eq(pict_type\,PICT_TYPE_I)" option to get only the I pictures out. To get the dc coeffs you will have to modify the decoder source code to get it out. I don't think you will directly find a tool to give it to you.

av501
  • 6,645
  • 2
  • 23
  • 34
  • thanks for this, could you plz write the complete command to get an I frame from (test.mp4) because iam trying but it not work ? – Saddam Aug 26 '12 at 19:24
  • i have the following command but still error ffmpeg -i test1.mp4 -vsync 0 -vf select="eq(pict_type\, PICT_TYPE_I)" I-Frm-%03d.jpeg – Saddam Aug 26 '12 at 19:52
  • Try only I instead of PICT_TYPE_I – av501 Aug 26 '12 at 19:53
  • This worked for me: Gave me a I pictures only formed video: ffmpeg -i a.mp4 -vsync 0 -vf select="eq(pict_type\,I)" -an -vcodec mpeg4 out.mp4. You can do the same and get jpegs if you want. – av501 Aug 26 '12 at 19:55
  • "ffmpeg -i test1.mp4 -vsync 0 -vf select="eq(pict_type\,I)" -an -f image2 thumbnails-%02d.jpeg " this command works ,NOW i will search how to get DC coefficients , wish me luck & thanks – Saddam Aug 26 '12 at 20:44
1

By using this command I'm able to extract the I-frames

ffmpeg -i input.flv -vf "select='eq(pict_type,PICT_TYPE_I)'" -vsync vfr thumb%04d.png
GShaik
  • 197
  • 1
  • 17