I am currently trying to extract every frame timestamp from an MPEG-4 file recorded using GoPro.
I want the exact time at which the frame was captured by the camera to combine this with computer vision algorithms later.
I know that the output frame rate is 25 frames per second. I extracted pts differently using ffmpeg and ffprobe, but all of them show too excellent results for me to believe.
Each frame / packet has an exact interval of 0.04 seconds (or 3600 points), which is convenient enough for an ideal 25 frames per second.
Commands I have used so far:
ffmpeg -i 3_96025.MP4 -an -vf showinfo %10d.png 2> res.txt
I also tried to use
ffmpeg -i 3_96025.MP4 **-copyts** -an -vf showinfo %10d.png 2> res.txt
but the results are exactly the same.
I also tried ffprobe :
ffprobe -i 396025.MP4 -show_packets -select_streams v
The bu intervals I get are perfect too.
I am sure the gopro will not be able to withstand 25 fps in this perfect way. In addition, I recorded a timer, and I see that each frame does not exactly correspond to an interval of 0.04 seconds. So, is there a way to see the time at which each frame was taken?
Here is the part of the output that I get with ffmpeg for reference:
frame= 42 fps= 26 q=0.0 size=N/A time=00:00:01.36 bitrate=N/A n:42 pts:151200 pts_time:1.68 pos:3232584 fmt:yuv420p sar:1/1 s:1280x960 i:P iskey:0 type:B checksum:6A83E942 plane_checksum:[1C859E55 79A4ED3E 28E25DA0] [Parsed_showinfo_0 @ 0037dea0] n:43 pts:154800 pts_time:1.72 pos:3255334 fmt:yuv420p sar:1/1 s:1280x960 i:P iskey:0 type:B checksum:5736F4C1 plane_checksum:[ACAD00D0 06FFDE34 65FA15BD] [Parsed_showinfo_0 @ 0037dea0] n:44 pts:158400 pts_time:1.76 pos:3083826 fmt:yuv420p sar:1/1 s:1280x960 i:P iskey:0 type:P checksum:9DD6B636 plane_checksum:[229400B3 7C0B52AF 75D162D4] [Parsed_showinfo_0 @ 0037dea0] n:45 pts:162000 pts_time:1.8 pos:3531851 fmt:yuv420p sar:1/1 s:1280x960 i:P iskey:0 type:B checksum:2DA4E2B9 plane_checksum:[9C646B9D 16F45382 28B0239A] [Parsed_showinfo_0 @ 0037dea0] n:46 pts:165600 pts_time:1.84 pos:3556346 fmt:yuv420p sar:1/1 s:1280x960 i:P iskey:0 type:B checksum:B4924AFE plane_checksum:[579EDD8F 94BC5C61 5B7F10FF] [Parsed_showinfo_0 @ 0037dea0] n:47 pts:169200 pts_time:1.88 pos:3279065 fmt:yuv420p sar:1/1 s:1280x960 i:P iskey:0 type:I checksum:DBB23A0C plane_checksum:[321835C9 57E9C9FB 576B3A39] [Parsed_showinfo_0 @ 0037dea0] n:48 pts:172800 pts_time:1.92 pos:3655246 fmt:yuv420p sar:1/1 s:1280x960 i:P iskey:0 type:B checksum:9BF3A47A plane_checksum:[4E17440B 3A059191 E394CECF] [Parsed_showinfo_0 @ 0037dea0] n:49 pts:176400 pts_time:1.96 pos:3677897 fmt:yuv420p sar:1/1 s:1280x960 i:P iskey:0 type:B checksum:2A3167B4 plane_checksum:[78601136 0A6F8334 272ED33B] [Parsed_showinfo_0 @ 0037dea0] n:50 pts:180000 pts_time:2 pos:3581296 fmt:yuv420p sar:1/1 s:1280x960 i:P iskey:0 type:P checksum:5A8C502E plane_checksum:[65A1FE60 0CEF07C3 F26149FC] [Parsed_showinfo_0 @ 0037dea0] n:51 pts:183600 pts_time:2.04 pos:3773963 fmt:yuv420p sar:1/1 s:1280x960 i:P iskey:0 type:B checksum:90572E41 plane_checksum:[E9478643 B8BAE0E2 E1A7C6FE] [Parsed_showinfo_0 @ 0037dea0] n:52 pts:187200 pts_time:2.08 pos:3797473 fmt:yuv420p sar:1/1 s:1280x960 i:P iskey:0 type:B checksum:2F206AB4 plane_checksum:[EB17F6AB 0AD1C78A E032AC61] [Parsed_showinfo_0 @ 0037dea0] n:53 pts:190800 pts_time:2.12 pos:3700340 fmt:yuv420p sar:1/1 s:1280x960 i:P iskey:0 type:P checksum:9A91E693 plane_checksum:[72309E37 229C34FB 59A71361] [Parsed_showinfo_0 @ 0037dea0] n:54 pts:194400 pts_time:2.16 pos:3897890 fmt:yuv420p sar:1/1 s:1280x960 i:P iskey:0 type:B checksum:BFCD3D1C plane_checksum:[13787B52 5F33F597 833ECC15] [Parsed_showinfo_0 @ 0037dea0] n:55 pts:198000 pts_time:2.2 pos:3919440 fmt:yuv420p sar:1/1 s:1280x960 i:P iskey:0 type:B checksum:62C6ED26 plane_checksum:[E4053A80 4752E0B5 E78FD1E2]
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