Hi guys I am involved with another project in computer forensic where I have to prove that several video files are intact (was not added or removed content). I thought it would be easy but I'm a little difficulty.
I thought of running ffprobe command to see the file characteristics and got the following output. ffprobe sample01.AVI... Input #0, avi, from 'sample01.AVI': Metadata: creation_time : 2012-05-15 17:37:35 encoder : SONY DSC MJPEG 0100 Duration: 00:00:46.27, start: 0.000000, bitrate: 2833 kb/s Stream #0:0: Video: mjpeg (MJPG / 0x47504A4D), yuvj422p(pc, bt470bg/unknown/unknown), 320x240, 2735 kb/s, 30 fps, 30 tbr, 30 tbn, 30 tbc Metadata: title : SONY DSC MOVIE Stream #0:1: Audio: pcm_mulaw ([7][0][0][0] / 0x0007), 11025 Hz, 1 channels, s16, 88 kb/s I converted the video time duration (00:00:46.27) for seconds and got the value: (46*60)+27 = 2767 s Give this value multiplied by the amount of 30 fps and obtained the following value: 2767 * 30 = 83610. I thought the logic was right, but to see the amount of frames in the video with the command: ffprobe -show_frames -select_streams v:0 sample01.AVI I got a output information and the final of message is: [FRAME]t message repeated 692 times media_type=video stream_index=0 key_frame=1 pkt_pts=1387 pkt_pts_time=46.232871 pkt_dts=1387 pkt_dts_time=46.232871 best_effort_timestamp=1387 best_effort_timestamp_time=46.232871 pkt_duration=1 pkt_duration_time=0.033333 pkt_pos=16330824 pkt_size=11662 width=320 height=240 pix_fmt=yuvj422p sample_aspect_ratio=N/A pict_type=I coded_picture_number=0 display_picture_number=0 interlaced_frame=0 top_field_first=0 repeat_pict=0 [/FRAME] I understand the output for the command, the pkt_pos line = 16330824 has the number of the frames in the video file. The calculated value (2767 * 30 = 83610) and read the value in the attribute (pkt_pos = 16,330,824) are vastly different. Can anybody help me to see where the error? An is a interpretation or arithmetic error? Please forgive the bad English! _______________________________________________ ffmpeg-user mailing list [email protected] http://ffmpeg.org/mailman/listinfo/ffmpeg-user To unsubscribe, visit link above, or email [email protected] with subject "unsubscribe".
