[FFmpeg-user] weird behavior with segmented files

Shaya Potter spotter at gmail.com
Thu Jul 14 06:16:41 EEST 2016


I'm playing around with using openrtsp (and vlc) to record my security
cameras and am trying to split the files.  However, while the saved
original file plays correctly, it seems the segmented files do not (in vlc
and totem).  While ffprobe shows that the initial frame in each is a
key_frame / I frame, I'm wondering if its an IDR frame as the image is
messed up (and fills in slowly) until it totally pops in (ala an IDR frame
is processed).

the way I split the original file is

ffmpeg -i test.mp4 -codec copy -map 0 -f segment -segment_list out.csv
-segment_times 30,60,90 -segment_time_delta 10 -reset_timestamps 1
out%03d.mp4

an example (out003.mp4 in the file set I'll reference below) first frame
from ffprobe shows

[FRAME]
media_type=video
stream_index=1
key_frame=1
pkt_pts=3840
pkt_pts_time=0.200000
pkt_dts=3840
pkt_dts_time=0.200000
best_effort_timestamp=3840
best_effort_timestamp_time=0.200000
pkt_duration=1280
pkt_duration_time=0.066667
pkt_pos=6931
pkt_size=35518
width=640
height=360
pix_fmt=yuv420p
sample_aspect_ratio=N/A
pict_type=I
coded_picture_number=2
display_picture_number=0
interlaced_frame=0
top_field_first=0
repeat_pict=0
[/FRAME]

which seems to indicate that its splitting on the correct frame but which
makes the fact that it doesnt render correctly for a few moments weird.

the files from my test are at http://www.cs.columbia.edu/~spotter/ffmpeg/

any help would be appreciated as I'm trying to learn and understand what's
going on and if there's  anything I can do about it.


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