[FFmpeg-trac] #2245(undetermined:closed): Speed difference when using -ss on similar MKVs when extracting frame image
FFmpeg
trac at avcodec.org
Thu Feb 7 14:44:22 CET 2013
#2245: Speed difference when using -ss on similar MKVs when extracting frame image
-------------------------------------+-------------------------------------
Reporter: eelco | Owner:
Type: defect | Status: closed
Priority: normal | Component:
Version: git-master | undetermined
Keywords: h264 mkv | Resolution: invalid
Blocking: | Blocked By:
Analyzed by developer: 0 | Reproduced by developer: 0
-------------------------------------+-------------------------------------
Comment (by eelco):
Interesting. I hadn’t looked at that yet. I saw that the “slow” sample
also has a keyframe at ~10.5 seconds and seeking to 11 seconds is indeed
fast. However, when I try the same on the original file, it is still slow.
(I created the slow file using the -t option and using the copy codec.)
I’ve created a new sample with dd that ''does'' have the same problem as
the original file though.
This is the keyframe information:
{{{
> ./ffprobe -of compact -show_frames ~/Desktop/ffmpeg-ss-bug/2245-slow-ss-
dd.mkv | grep 'video|key_frame=1'
... (still the same ffmpeg version)
frame|media_type=video|key_frame=1|pkt_pts=0|pkt_pts_time=0.000000|pkt_dts=0|pkt_dts_time=0.000000|pkt_duration=N/A|pkt_duration_time=N/A|pkt_pos=6670|pkt_size=148182|width=1920|height=1080|pix_fmt=yuv420p|sample_aspect_ratio=1:1|pict_type=I|coded_picture_number=0|display_picture_number=0|interlaced_frame=0|top_field_first=0|repeat_pict=0|reference=3
frame|media_type=video|key_frame=1|pkt_pts=10427|pkt_pts_time=10.427000|pkt_dts=10427|pkt_dts_time=10.427000|pkt_duration=41|pkt_duration_time=0.041000|pkt_pos=13743718|pkt_size=99527|width=1920|height=1080|pix_fmt=yuv420p|sample_aspect_ratio=1:1|pict_type=I|coded_picture_number=250|display_picture_number=0|interlaced_frame=0|top_field_first=0|repeat_pict=0|reference=3
}}}
Since there is a keyframe at 10.427, I’d expect getting the image at 11
seconds would be pretty fast, but it isn’t:
{{{
time ./ffmpeg "-ss" "11" "-i" ~/Desktop/ffmpeg-ss-bug/2245-slow-ss-dd.mkv
"-f" "image2" "-vframes" "1" /dev/null
ffmpeg version N-49666-g4745194 Copyright (c) 2000-2013 the FFmpeg
developers
built on Feb 7 2013 10:22:14 with llvm-gcc 4.2.1 (LLVM build
2336.11.00)
configuration: --prefix=/Users/eelco/Projects/Beamer/FFmpeg/build
--enable-gpl --enable-version3 --enable-libx264 --disable-shared --enable-
static --enable-libtheora --enable-libvorbis --enable-libvo-aacenc
--disable-doc --extra-cflags='-DMACOSX_DEPLOYMENT_TARGET=10.6 -isysroot
/Applications/Xcode.app/Contents/Developer/Platforms/MacOSX.platform/Developer/SDKs/MacOSX10.8.sdk
-mmacosx-version-min=10.6
-I/Users/eelco/Projects/Beamer/FFmpeg/build/include' --extra-
ldflags='-isysroot
/Applications/Xcode.app/Contents/Developer/Platforms/MacOSX.platform/Developer/SDKs/MacOSX10.8.sdk
-mmacosx-version-min=10.6 -L/Users/eelco/Projects/Beamer/FFmpeg/build/lib'
libavutil 52. 17.101 / 52. 17.101
libavcodec 54. 91.101 / 54. 91.101
libavformat 54. 61.104 / 54. 61.104
libavdevice 54. 3.103 / 54. 3.103
libavfilter 3. 35.101 / 3. 35.101
libswscale 2. 2.100 / 2. 2.100
libswresample 0. 17.102 / 0. 17.102
libpostproc 52. 2.100 / 52. 2.100
Input #0, matroska,webm, from '/Users/eelco/Desktop/ffmpeg-ss-bug/2245
-slow-ss-dd.mkv':
Metadata:
creation_time : 2012-12-09 16:32:15
Duration: 01:33:24.19, start: 0.000000, bitrate: 21 kb/s
Chapter #0.0: start 0.000000, end 316.316000
Metadata:
title : 00:00:00.000
Chapter #0.1: start 316.316000, end 651.985000
Metadata:
title : 00:05:16.316
Chapter #0.2: start 651.985000, end 1186.310000
Metadata:
title : 00:10:51.985
Chapter #0.3: start 1186.310000, end 1669.835000
Metadata:
title : 00:19:46.310
Chapter #0.4: start 1669.835000, end 1970.552000
Metadata:
title : 00:27:49.835
Chapter #0.5: start 1970.552000, end 2434.974000
Metadata:
title : 00:32:50.552
Chapter #0.6: start 2434.974000, end 2811.976000
Metadata:
title : 00:40:34.974
Chapter #0.7: start 2811.976000, end 3120.534000
Metadata:
title : 00:46:51.976
Chapter #0.8: start 3120.534000, end 3535.157000
Metadata:
title : 00:52:00.534
Chapter #0.9: start 3535.157000, end 3623.411000
Metadata:
title : 00:58:55.157
Chapter #0.10: start 3623.411000, end 3859.314000
Metadata:
title : 01:00:23.411
Chapter #0.11: start 3859.314000, end 4259.672000
Metadata:
title : 01:04:19.314
Chapter #0.12: start 4259.672000, end 4530.317000
Metadata:
title : 01:10:59.672
Chapter #0.13: start 4530.317000, end 4869.782000
Metadata:
title : 01:15:30.317
Chapter #0.14: start 4869.782000, end 4968.630000
Metadata:
title : 01:21:09.782
Chapter #0.15: start 4968.630000, end 5604.192000
Metadata:
title : 01:22:48.630
Stream #0:0(eng): Video: h264 (High), yuv420p, 1920x1080, SAR 1:1 DAR
16:9, 23.98 fps, 23.98 tbr, 1k tbn, 47.95 tbc (default)
Stream #0:1(eng): Audio: truehd, 48000 Hz, 7.1, s32
Metadata:
title : English TRUE-HD
Stream #0:2(swe): Audio: ac3, 48000 Hz, 5.1(side), fltp, 640 kb/s
(default)
Metadata:
title : Swedish AC3
Stream #0:3(swe): Subtitle: dvd_subtitle (default)
Metadata:
title : Swedish
Stream #0:4(eng): Subtitle: dvd_subtitle
Metadata:
title : English
Output #0, image2, to '/dev/null':
Metadata:
encoder : Lavf54.61.104
Chapter #0.0: start 0.000000, end 305.316000
Metadata:
title : 00:00:00.000
Chapter #0.1: start 305.316000, end 640.985000
Metadata:
title : 00:05:16.316
Chapter #0.2: start 640.985000, end 1175.310000
Metadata:
title : 00:10:51.985
Chapter #0.3: start 1175.310000, end 1658.835000
Metadata:
title : 00:19:46.310
Chapter #0.4: start 1658.835000, end 1959.552000
Metadata:
title : 00:27:49.835
Chapter #0.5: start 1959.552000, end 2423.974000
Metadata:
title : 00:32:50.552
Chapter #0.6: start 2423.974000, end 2800.976000
Metadata:
title : 00:40:34.974
Chapter #0.7: start 2800.976000, end 3109.534000
Metadata:
title : 00:46:51.976
Chapter #0.8: start 3109.534000, end 3524.157000
Metadata:
title : 00:52:00.534
Chapter #0.9: start 3524.157000, end 3612.411000
Metadata:
title : 00:58:55.157
Chapter #0.10: start 3612.411000, end 3848.314000
Metadata:
title : 01:00:23.411
Chapter #0.11: start 3848.314000, end 4248.672000
Metadata:
title : 01:04:19.314
Chapter #0.12: start 4248.672000, end 4519.317000
Metadata:
title : 01:10:59.672
Chapter #0.13: start 4519.317000, end 4858.782000
Metadata:
title : 01:15:30.317
Chapter #0.14: start 4858.782000, end 4957.630000
Metadata:
title : 01:21:09.782
Chapter #0.15: start 4957.630000, end 5593.192000
Metadata:
title : 01:22:48.630
Stream #0:0(eng): Video: mjpeg, yuvj420p, 1920x1080 [SAR 1:1 DAR
16:9], q=2-31, 200 kb/s, 90k tbn, 23.98 tbc (default)
Stream mapping:
Stream #0:0 -> #0:0 (h264 -> mjpeg)
Press [q] to stop, [?] for help
frame= 1 fps=0.5 q=0.0 Lsize=N/A time=00:00:00.04 bitrate=N/A dup=0
drop=262
video:47kB audio:0kB subtitle:0 global headers:0kB muxing overhead
-100.045473%
2.14 real 6.04 user 0.10 sys
}}}
I’ve uploaded the file to the FTP.
--
Ticket URL: <https://ffmpeg.org/trac/ffmpeg/ticket/2245#comment:3>
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