[Libav-user] about video duration

[YIRAN LI]

Hi friends,


I'm now checking a duration issue of a video file.
Here is some trace print out when file is opened, so we can know the dts of
last AVPacket is 167542, and the last frame  time stamp = 167376, and
coded_picture_num = 4013


  Line 100: 00:00:33.384 MAIN rhbc73 process packet, Packet.dts = 0,
Packet.pts = -9223372036854775808 Line 101: 00:00:33.384 MAIN rhbc73
process packet, Packet.dts = 42, Packet.pts = -9223372036854775808 Line
102: 00:00:33.400 MAIN rhbc73 process packet, Packet.dts = 83, Packet.pts =
-9223372036854775808 Line 103: 00:00:33.400 MAIN rhbc73 process packet,
Packet.dts = 125, Packet.pts = -9223372036854775808 Line 104: 00:00:33.400
MAIN rhbc73 process packet, Packet.dts = 167, Packet.pts =
-9223372036854775808 Line 105: 00:00:33.400 MAIN rhbc73 -- get a full
frame, pFrame->pkt_dts = 0, pFrame->pkt_pts = -9223372036854775808,
BestEffortTimeStamp = 0, pFrame->coded_picture_number = 0 Line 107:
00:00:33.400 MAIN rhbc73 process packet, Packet.dts = 209, Packet.pts =
-9223372036854775808 Line 108: 00:00:33.400 MAIN rhbc73 -- get a full
frame, pFrame->pkt_dts = 42, pFrame->pkt_pts = -9223372036854775808,
BestEffortTimeStamp = 42, pFrame->coded_picture_number = 1 Line 110:
00:00:33.400 MAIN rhbc73 process packet, Packet.dts = 250, Packet.pts =
-9223372036854775808 Line 111: 00:00:33.416 MAIN rhbc73 -- get a full
frame, pFrame->pkt_dts = 83, pFrame->pkt_pts = -9223372036854775808,
BestEffortTimeStamp = 83, pFrame->coded_picture_number = 2 Line 113:
00:00:33.416 MAIN rhbc73 process packet, Packet.dts = 292, Packet.pts =
-9223372036854775808 Line 114: 00:00:33.416 MAIN rhbc73 -- get a full
frame, pFrame->pkt_dts = 125, pFrame->pkt_pts = -9223372036854775808,
BestEffortTimeStamp = 125, pFrame->coded_picture_number = 3 Line 116:
00:00:33.416 MAIN rhbc73 process packet, Packet.dts = 334, Packet.pts =
-9223372036854775808 Line 117: 00:00:33.416 MAIN rhbc73 -- get a full
frame, pFrame->pkt_dts = 167, pFrame->pkt_pts = -9223372036854775808,
BestEffortTimeStamp = 167, pFrame->coded_picture_number = 4 Line 119:
00:00:33.416 MAIN rhbc73 process packet, Packet.dts = 375, Packet.pts =
-9223372036854775808 Line 120: 00:00:33.416 MAIN rhbc73 -- get a full
frame, pFrame->pkt_dts = 209, pFrame->pkt_pts = -9223372036854775808,
BestEffortTimeStamp = 209, pFrame->coded_picture_number = 5 Line 122:
00:00:33.416 MAIN rhbc73 process packet, Packet.dts = 417, Packet.pts =
-9223372036854775808 Line 123: 00:00:33.416 MAIN rhbc73 -- get a full
frame, pFrame->pkt_dts = 250, pFrame->pkt_pts = -9223372036854775808,
BestEffortTimeStamp = 250, pFrame->coded_picture_number = 6 Line 125:
00:00:33.416 MAIN rhbc73 process packet, Packet.dts = 459, Packet.pts =
-9223372036854775808 Line 126: 00:00:33.416 MAIN rhbc73 -- get a full
frame, pFrame->pkt_dts = 292, pFrame->pkt_pts = -9223372036854775808,
BestEffortTimeStamp = 292, pFrame->coded_picture_number = 7 Line 128:
00:00:33.416 MAIN rhbc73 process packet, Packet.dts = 501, Packet.pts =
-9223372036854775808 Line 129: 00:00:33.416 MAIN rhbc73 -- get a full
frame, pFrame->pkt_dts = 334, pFrame->pkt_pts = -9223372036854775808,
BestEffortTimeStamp = 334, pFrame->coded_picture_number = 8 Line 131:
00:00:33.416 MAIN rhbc73 process packet, Packet.dts = 542, Packet.pts =
-9223372036854775808 Line 132: 00:00:33.416 MAIN rhbc73 -- get a full
frame, pFrame->pkt_dts = 375, pFrame->pkt_pts = -9223372036854775808,
BestEffortTimeStamp = 375, pFrame->coded_picture_number = 9 Line 12134:
00:00:51.168 MAIN rhbc73 process packet, Packet.dts = 167417, Packet.pts =
-9223372036854775808 Line 12135: 00:00:51.168 MAIN rhbc73 -- get a full
frame, pFrame->pkt_dts = 167250, pFrame->pkt_pts = -9223372036854775808,
BestEffortTimeStamp = 167250, pFrame->coded_picture_number = 4010 Line
12137: 00:00:51.168 MAIN rhbc73 process packet, Packet.dts = 167459,
Packet.pts = -9223372036854775808 Line 12138: 00:00:51.168 MAIN rhbc73 --
get a full frame, pFrame->pkt_dts = 167292, pFrame->pkt_pts =
-9223372036854775808, BestEffortTimeStamp = 167292,
pFrame->coded_picture_number = 4011 Line 12140: 00:00:51.168 MAIN rhbc73
process packet, Packet.dts = 167501, Packet.pts = -9223372036854775808 Line
12141: 00:00:51.168 MAIN rhbc73 -- get a full frame, pFrame->pkt_dts =
167334, pFrame->pkt_pts = -9223372036854775808, BestEffortTimeStamp =
167334, pFrame->coded_picture_number = 4012 Line 12143: 00:00:51.184 MAIN
rhbc73 process packet, Packet.dts = 167542, Packet.pts =
-9223372036854775808 Line 12144: 00:00:51.184 MAIN rhbc73 -- get a full
frame, pFrame->pkt_dts = 167376, pFrame->pkt_pts = -9223372036854775808,
BestEffortTimeStamp = 167376, pFrame->coded_picture_number = 4013

But when I check the file using ffprobe -show_frames -select_streams v
input I could see

[FRAME]
media_type=video
key_frame=0
pkt_pts=N/A
pkt_pts_time=N/A
pkt_dts=167501
pkt_dts_time=167.501000
pkt_duration=N/A
pkt_duration_time=N/A
pkt_pos=103794518
pkt_size=74
width=1920
height=1080
pix_fmt=yuv420p
sample_aspect_ratio=1:1
pict_type=P
coded_picture_number=4016
display_picture_number=0
interlaced_frame=0
top_field_first=0
repeat_pict=0
[/FRAME]
[FRAME]
media_type=video
key_frame=0
pkt_pts=N/A
pkt_pts_time=N/A
pkt_dts=167542
pkt_dts_time=167.542000
pkt_duration=N/A
pkt_duration_time=N/A
pkt_pos=103794920
pkt_size=74
width=1920
height=1080
pix_fmt=yuv420p
sample_aspect_ratio=1:1
pict_type=P
coded_picture_number=4017
display_picture_number=0
interlaced_frame=0
top_field_first=0
repeat_pict=0
[/FRAME]

the ffprobe and ffmpeg libs were built from same latest source, so I'd like
to know why ffprobe could dump a last frame of timestamp 167542 but
av_read_frame + avcodec_decode_video2
couldn't


Thanks
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