[mythtv-commits] Ticket #12010: mythcommflag --rebuild does not re-create good seektables with h264 recordings

[MythTV]

#12010: mythcommflag --rebuild does not re-create good seektables with h264
recordings
-----------------------------------------+-----------------------------
 Reporter:  J.Pilk@…                     |          Owner:  pbennett
     Type:  Bug Report - General         |         Status:  assigned
 Priority:  minor                        |      Milestone:  unknown
Component:  MythTV - Video Decoding      |        Version:  Master Head
 Severity:  medium                       |     Resolution:
 Keywords:  mythcommflag --rebuild h264  |  Ticket locked:  0
-----------------------------------------+-----------------------------

Comment (by johnpilk222@…):

 Continuing from comment 19 above:  I've made a little progress in using
 ffprobe and can now see where it thinks keyframes are.  I suspect that the
 lack of cutting-precision in my script may have more to do with the
 handling of timecodes, but here's some food for thought from a very short
 recording from BBC ONE HD DVB-T2


 {{{

 [john at HP_Fed ~]$  ffprobe -show_frames
 "/home/john/SGs/RecsSG2/21540_20180415204200.ts_24722in.ts"  2> /dev/null
 | grep -B16 -A1 pict_type=I  | head -n 18
 This is from the raw recording

 stream_index=0
 key_frame=1
 pkt_pts=5493778274
 pkt_pts_time=61041.980822
 pkt_dts=5493778274
 pkt_dts_time=61041.980822
 best_effort_timestamp=5493778274
 best_effort_timestamp_time=61041.980822
 pkt_duration=3600
 pkt_duration_time=0.040000
 pkt_pos=89864
 pkt_size=92220
 width=1920
 height=1080
 pix_fmt=yuv420p
 sample_aspect_ratio=1:1
 pict_type=I
 coded_picture_number=11

 [john at HP_Fed ~]$  ffprobe -show_frames
 "/home/john/SGs/RecsSG2/21540_20180415204200.ts_25372in.ts"  2> /dev/null
 | grep -B16 -A1 pict_type=I  | head -n 18
 This is from mythTScut R 1 NC on the raw recording

 stream_index=0
 key_frame=1
 pkt_pts=274007
 pkt_pts_time=3.044522
 pkt_dts=274007
 pkt_dts_time=3.044522
 best_effort_timestamp=274007
 best_effort_timestamp_time=3.044522
 pkt_duration=3600
 pkt_duration_time=0.040000
 pkt_pos=22184
 pkt_size=92220
 width=1920
 height=1080
 pix_fmt=yuv420p
 sample_aspect_ratio=1:1
 pict_type=I
 coded_picture_number=4
 [john at HP_Fed ~]$

 [john at HP_Fed ~]$  ffprobe -show_frames
 "/home/john/SGs/RecsSG2/21540_20180415204200.ts"  2> /dev/null | grep -B16
 -A1 pict_type=I  | head -n 18
 This is from a segment cut out by mythTScut R 1 from the file above

 stream_index=0
 key_frame=1
 pkt_pts=181007
 pkt_pts_time=2.011189
 pkt_dts=181007
 pkt_dts_time=2.011189
 best_effort_timestamp=181007
 best_effort_timestamp_time=2.011189
 pkt_duration=3600
 pkt_duration_time=0.040000
 pkt_pos=3760
 pkt_size=126831
 width=1920
 height=1080
 pix_fmt=yuv420p
 sample_aspect_ratio=1:1
 pict_type=I
 coded_picture_number=4


 [john at HP_Fed ~]$  ffprobe -show_frames
 "/home/john/SGs/RecsSG2/21540_20180415204200.ts"  2> /dev/null | grep -A1
 pict_type=I | head -n 20
 From the same cutout segment

 Keyframes from the editor are 1, 25, 49, 73, 83, 110, 134

 pict_type=I
 coded_picture_number=4
 --
 pict_type=I
 coded_picture_number=28
 --
 pict_type=I
 coded_picture_number=52
 --
 pict_type=I
 coded_picture_number=76
 --
 pict_type=I
 coded_picture_number=86
 --
 pict_type=I
 coded_picture_number=113
 --
 pict_type=I
 coded_picture_number=137
 [john at HP_Fed ~]$

 [john at HP_Fed ~]$  ffprobe -show_frames
 "/home/john/SGs/RecsSG2/21540_20180415204200.ts_24722in.ts"  2> /dev/null
 | grep -A1 pict_type=I  | head -n 20
 The raw recording again

 Keyframes from the editor are 1, 25, 49, 64, 91, 115, 142

 pict_type=I
 coded_picture_number=11
 --
 pict_type=I
 coded_picture_number=35
 --
 pict_type=I
 coded_picture_number=59
 --
 pict_type=I
 coded_picture_number=74
 --
 pict_type=I
 coded_picture_number=101
 --
 pict_type=I
 coded_picture_number=125
 --
 pict_type=I
 coded_picture_number=152


 }}}

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Ticket URL: <https://code.mythtv.org/trac/ticket/12010#comment:22>
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