MP4Box.js not correctly detecting i-frames

[louderspace]

This file, exported from Adobe Media Encoder uses a keyframe distance of 33. Therefore, every 33 samples should be a sync frame. ffprobe correctly lists the sync frames, but MP4Box.js does not.

Numbers-H265-GOP33.mp4

[louderspace]

Note,

ffprobe -show_frames -select_streams v:0 \
-print_format csv Numbers-H265-GOP33.mp4

Produces:

frame,video,0,1,0,0.000000,0,0.000000,0,0.000000,1000,0.016667,1000,0.016667,70615,1280,320,240,yuv420p,N/A,I,0,0,0,0,0,tv,smpte170m,smpte170m,bt709,left,side_data,H.26[45] User Data Unregistered SEI message

frame,video,0,0,1000,0.016667,1000,0.016667,1000,0.016667,1000,0.016667,1000,0.016667,73889,455,320,240,yuv420p,N/A,B,0,0,0,0,0,tv,smpte170m,smpte170m,bt709,left
frame,video,0,0,2000,0.033333,2000,0.033333,2000,0.033333,1000,0.016667,1000,0.016667,72763,1126,320,240,yuv420p,N/A,B,0,0,0,0,0,tv,smpte170m,smpte170m,bt709,left
frame,video,0,0,3000,0.050000,3000,0.050000,3000,0.050000,1000,0.016667,1000,0.016667,74344,1171,320,240,yuv420p,N/A,B,0,0,0,0,0,tv,smpte170m,smpte170m,bt709,left
frame,video,0,0,4000,0.066667,4000,0.066667,4000,0.066667,1000,0.016667,1000,0.016667,71895,868,320,240,yuv420p,N/A,P,0,0,0,0,0,tv,smpte170m,smpte170m,bt709,left
frame,video,0,0,5000,0.083333,5000,0.083333,5000,0.083333,1000,0.016667,1000,0.016667,78430,1092,320,240,yuv420p,N/A,B,0,0,0,0,0,tv,smpte170m,smpte170m,bt709,left
frame,video,0,0,6000,0.100000,6000,0.100000,6000,0.100000,1000,0.016667,1000,0.016667,77011,1419,320,240,yuv420p,N/A,B,0,0,0,0,0,tv,smpte170m,smpte170m,bt709,left
frame,video,0,0,7000,0.116667,7000,0.116667,7000,0.116667,1000,0.016667,1000,0.016667,79522,680,320,240,yuv420p,N/A,B,0,0,0,0,0,tv,smpte170m,smpte170m,bt709,left
frame,video,0,0,8000,0.133333,8000,0.133333,8000,0.133333,1000,0.016667,1000,0.016667,75515,1496,320,240,yuv420p,N/A,P,0,0,0,0,0,tv,smpte170m,smpte170m,bt709,left
frame,video,0,0,9000,0.150000,9000,0.150000,9000,0.150000,1000,0.016667,1000,0.016667,89785,1154,320,240,yuv420p,N/A,B,0,0,0,0,0,tv,smpte170m,smpte170m,bt709,left
frame,video,0,0,10000,0.166667,10000,0.166667,10000,0.166667,1000,0.016667,1000,0.016667,88233,1552,320,240,yuv420p,N/A,B,0,0,0,0,0,tv,smpte170m,smpte170m,bt709,left
frame,video,0,0,11000,0.183333,11000,0.183333,11000,0.183333,1000,0.016667,1000,0.016667,90939,326,320,240,yuv420p,N/A,B,0,0,0,0,0,tv,smpte170m,smpte170m,bt709,left
frame,video,0,0,12000,0.200000,12000,0.200000,12000,0.200000,1000,0.016667,1000,0.016667,80202,1940,320,240,yuv420p,N/A,P,0,0,0,0,0,tv,smpte170m,smpte170m,bt709,left
frame,video,0,0,13000,0.216667,13000,0.216667,13000,0.216667,1000,0.016667,1000,0.016667,93948,1457,320,240,yuv420p,N/A,B,0,0,0,0,0,tv,smpte170m,smpte170m,bt709,left
frame,video,0,0,14000,0.233333,14000,0.233333,14000,0.233333,1000,0.016667,1000,0.016667,93062,886,320,240,yuv420p,N/A,B,0,0,0,0,0,tv,smpte170m,smpte170m,bt709,left
frame,video,0,0,15000,0.250000,15000,0.250000,15000,0.250000,1000,0.016667,1000,0.016667,95405,1158,320,240,yuv420p,N/A,B,0,0,0,0,0,tv,smpte170m,smpte170m,bt709,left
frame,video,0,0,16000,0.266667,16000,0.266667,16000,0.266667,1000,0.016667,1000,0.016667,91265,1797,320,240,yuv420p,N/A,P,0,0,0,0,0,tv,smpte170m,smpte170m,bt709,left
frame,video,0,0,17000,0.283333,17000,0.283333,17000,0.283333,1000,0.016667,1000,0.016667,100882,855,320,240,yuv420p,N/A,B,0,0,0,0,0,tv,smpte170m,smpte170m,bt709,left
frame,video,0,0,18000,0.300000,18000,0.300000,18000,0.300000,1000,0.016667,1000,0.016667,99149,1733,320,240,yuv420p,N/A,B,0,0,0,0,0,tv,smpte170m,smpte170m,bt709,left
frame,video,0,0,19000,0.316667,19000,0.316667,19000,0.316667,1000,0.016667,1000,0.016667,108508,1624,320,240,yuv420p,N/A,B,0,0,0,0,0,tv,smpte170m,smpte170m,bt709,left
frame,video,0,0,20000,0.333333,20000,0.333333,20000,0.333333,1000,0.016667,1000,0.016667,96563,2586,320,240,yuv420p,N/A,P,0,0,0,0,0,tv,smpte170m,smpte170m,bt709,left
frame,video,0,0,21000,0.350000,21000,0.350000,21000,0.350000,1000,0.016667,1000,0.016667,112634,558,320,240,yuv420p,N/A,B,0,0,0,0,0,tv,smpte170m,smpte170m,bt709,left
frame,video,0,0,22000,0.366667,22000,0.366667,22000,0.366667,1000,0.016667,1000,0.016667,111277,1357,320,240,yuv420p,N/A,B,0,0,0,0,0,tv,smpte170m,smpte170m,bt709,left
frame,video,0,0,23000,0.383333,23000,0.383333,23000,0.383333,1000,0.016667,1000,0.016667,113192,1714,320,240,yuv420p,N/A,B,0,0,0,0,0,tv,smpte170m,smpte170m,bt709,left
frame,video,0,0,24000,0.400000,24000,0.400000,24000,0.400000,1000,0.016667,1000,0.016667,110132,1145,320,240,yuv420p,N/A,P,0,0,0,0,0,tv,smpte170m,smpte170m,bt709,left
frame,video,0,0,25000,0.416667,25000,0.416667,25000,0.416667,1000,0.016667,1000,0.016667,118537,1091,320,240,yuv420p,N/A,B,0,0,0,0,0,tv,smpte170m,smpte170m,bt709,left
frame,video,0,0,26000,0.433333,26000,0.433333,26000,0.433333,1000,0.016667,1000,0.016667,116865,1672,320,240,yuv420p,N/A,B,0,0,0,0,0,tv,smpte170m,smpte170m,bt709,left
frame,video,0,0,27000,0.450000,27000,0.450000,27000,0.450000,1000,0.016667,1000,0.016667,119628,828,320,240,yuv420p,N/A,B,0,0,0,0,0,tv,smpte170m,smpte170m,bt709,left
frame,video,0,0,28000,0.466667,28000,0.466667,28000,0.466667,1000,0.016667,1000,0.016667,114906,1959,320,240,yuv420p,N/A,P,0,0,0,0,0,tv,smpte170m,smpte170m,bt709,left
frame,video,0,0,29000,0.483333,29000,0.483333,29000,0.483333,1000,0.016667,1000,0.016667,131556,1592,320,240,yuv420p,N/A,B,0,0,0,0,0,tv,smpte170m,smpte170m,bt709,left
frame,video,0,0,30000,0.500000,30000,0.500000,30000,0.500000,1000,0.016667,1000,0.016667,130190,1366,320,240,yuv420p,N/A,B,0,0,0,0,0,tv,smpte170m,smpte170m,bt709,left
frame,video,0,0,31000,0.516667,31000,0.516667,31000,0.516667,1000,0.016667,1000,0.016667,133148,531,320,240,yuv420p,N/A,B,0,0,0,0,0,tv,smpte170m,smpte170m,bt709,left
frame,video,0,0,32000,0.533333,32000,0.533333,32000,0.533333,1000,0.016667,1000,0.016667,120456,2964,320,240,yuv420p,N/A,P,0,0,0,0,0,tv,smpte170m,smpte170m,bt709,left
frame,video,0,1,33000,0.550000,33000,0.550000,33000,0.550000,1000,0.016667,1000,0.016667,133679,3644,320,240,yuv420p,N/A,I,0,0,0,0,0,tv,smpte170m,smpte170m,bt709,left
frame,video,0,0,34000,0.566667,34000,0.566667,34000,0.566667,1000,0.016667,1000,0.016667,139512,1049,320,240,yuv420p,N/A,B,0,0,0,0,0,tv,smpte170m,smpte170m,bt709,left
.....