[FFmpeg-trac] #4028(avfilter:new): Videofilter "fps" to extract images each minute starts at 30 seconds offset
FFmpeg
trac at avcodec.org
Tue Oct 14 13:37:54 CEST 2014
#4028: Videofilter "fps" to extract images each minute starts at 30 seconds offset
-------------------------------------+-------------------------------------
Reporter: peter_b | Type: defect
Status: new | Priority: normal
Component: avfilter | Version: git-
Keywords: thumbnail | master
images | Blocked By:
Blocking: | Reproduced by developer: 0
Analyzed by developer: 0 |
-------------------------------------+-------------------------------------
Summary of the bug:
I wanted to extract an image at exactly every minute from a video, as
described in the wiki article "[[Create a thumbnail image every X seconds
of the video]]".
I expected to get images for positions 0s, 60s, 120s, etc.
But the result is: 0s, 30s, 90s, 150s, etc.
How to reproduce:
'''1) Generate a testvideo with time-information (seconds) in the
image:'''
{{{
ffmpeg -t 300 -f lavfi -i testsrc -an -y -c:v ffv1 test.avi
}}}
'''2) Extract images using the "fps" video filter:'''
{{{
ffmpeg_git -i test.avi -vf fps=fps=1/60 -f image2 image%03d.jpg
}}}
Complete, uncut console output:
{{{
ffmpeg version N-66851-gd58fa94 Copyright (c) 2000-2014 the FFmpeg
developers
built on Oct 14 2014 11:43:57 with gcc 4.4.5 (Debian 4.4.5-8)
configuration: --prefix=/usr/local --enable-gpl --enable-nonfree
--enable-version3 --enable-postproc --enable-swscale --enable-avfilter
--enable-pthreads --enable-bzlib --enable-zlib --enable-libvorbis
--enable-libopenjpeg --enable-decoder=png --enable-encoder=png --disable-
decoder=jpeg2000 --enable-libfreetype --enable-libschroedinger --enable-
libx264 --enable-libfaac --enable-libmp3lame
libavutil 54. 10.100 / 54. 10.100
libavcodec 56. 5.100 / 56. 5.100
libavformat 56. 9.100 / 56. 9.100
libavdevice 56. 1.100 / 56. 1.100
libavfilter 5. 1.105 / 5. 1.105
libswscale 3. 1.101 / 3. 1.101
libswresample 1. 1.100 / 1. 1.100
libpostproc 53. 3.100 / 53. 3.100
Input #0, avi, from 'test.avi':
Metadata:
encoder : Lavf56.9.100
Duration: 00:05:00.00, start: 0.000000, bitrate: 886 kb/s
Stream #0:0: Video: ffv1 (FFV1 / 0x31564646), bgr0, 320x240, 881 kb/s,
SAR 1:1 DAR 4:3, 25 fps, 25 tbr, 25 tbn, 25 tbc
[swscaler @ 0x9abf040] deprecated pixel format used, make sure you did set
range correctly
[mjpeg @ 0x9ad5180] bitrate tolerance 4000000 too small for bitrate
200000, overriding
Output #0, image2, to 'image%03d.jpg':
Metadata:
encoder : Lavf56.9.100
Stream #0:0: Video: mjpeg, yuvj444p(pc), 320x240 [SAR 1:1 DAR 4:3],
q=2-31, 200 kb/s, 0.02 fps, 0.02 tbn, 0.02 tbc
Metadata:
encoder : Lavc56.5.100 mjpeg
Stream mapping:
Stream #0:0 -> #0:0 (ffv1 (native) -> mjpeg (native))
Press [q] to stop, [?] for help
frame= 6 fps=0.3 q=1.6 Lsize=N/A time=00:06:00.00 bitrate=N/A
video:84kB audio:0kB subtitle:0kB other streams:0kB global headers:0kB
muxing overhead: unknown
}}}
The images are taken from the following positions (in seconds):
0, 30, 90, 150, 210, 270
It ''should'' be:
0, 60, 120, 180, 240, 300
--
Ticket URL: <https://trac.ffmpeg.org/ticket/4028>
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