On 10-03-2020 12:49 pm, Alex Teslik wrote:
Hello,
I have an image sequence of line drawings where the drawings change
abruptly. Ffmpeg is resetting the frame numbers that I am burning in using the
drawtext option every time there is an abrupt change. Here is the command I am
using, and the output:
ffmpeg.exe -y -r 10 -i final-%d.png -vf
"drawtext=fontfile='C\:/WINDOWS/fonts/arialbd.ttf':text=%
{frame_num}:start_number=1:fontcolor=black:fontsize=15:x=10:y=10,fps=10" -
pix_fmt rgb24 -c:v qtrle -r 10 test.mov
ffmpeg version git-2020-02-18-ebee808 Copyright (c) 2000-2020 the FFmpeg
developers
built with gcc 9.2.1 (GCC) 20200122
configuration: --enable-gpl --enable-version3 --enable-sdl2 --enable-
fontconfig --enable-gnutls --enable-iconv --enable-libass --enable-libdav1d --
enable-libbluray --enable-libfreetype --enable-libmp3lame --enable-
libopencore-amrnb --enable-libopencore-amrwb --enable-libopenjpeg --enable-
libopus --enable-libshine --enable-libsnappy --enable-libsoxr --enable-
libtheora --enable-libtwolame --enable-libvpx --enable-libwavpack --enable-
libwebp --enable-libx264 --enable-libx265 --enable-libxml2 --enable-libzimg --
enable-lzma --enable-zlib --enable-gmp --enable-libvidstab --enable-libvorbis
--enable-libvo-amrwbenc --enable-libmysofa --enable-libspeex --enable-libxvid
--enable-libaom --enable-libmfx --enable-ffnvcodec --enable-cuvid --enable-
d3d11va --enable-nvenc --enable-nvdec --enable-dxva2 --enable-avisynth --
enable-libopenmpt --enable-amf
libavutil 56. 41.100 / 56. 41.100
libavcodec 58. 70.100 / 58. 70.100
libavformat 58. 38.101 / 58. 38.101
libavdevice 58. 9.103 / 58. 9.103
libavfilter 7. 76.100 / 7. 76.100
libswscale 5. 6.100 / 5. 6.100
libswresample 3. 6.100 / 3. 6.100
libpostproc 55. 6.100 / 55. 6.100
Input #0, image2, from 'final-%d.png':
Duration: 00:00:04.96, start: 0.000000, bitrate: N/A
Stream #0:0: Video: png, gray(pc), 240x196 [SAR 7559:7559 DAR 60:49], 25
fps, 25 tbr, 25 tbn, 25 tbc
Stream mapping:
Stream #0:0 -> #0:0 (png (native) -> qtrle (native))
Press [q] to stop, [?] for help
Output #0, mov, to 'test.mov':
Metadata:
encoder : Lavf58.38.101
Stream #0:0: Video: qtrle (rle / 0x20656C72), rgb24, 240x196 [SAR 1:1 DAR
60:49], q=2-31, 200 kb/s, 10 fps, 10240 tbn, 10 tbc
Metadata:
encoder : Lavc58.70.100 qtrle
frame= 124 fps=0.0 q=-0.0 Lsize= 635kB time=00:00:12.30 bitrate=
422.9kbits/s dup=3 drop=0 speed=92.5x
video:634kB audio:0kB subtitle:0kB other streams:0kB global headers:0kB muxing
overhead: 0.200005%
The images start at 1 and sequentially increment. But when the image changes
dramatically, the frame numbering starts over at 1 again. So out of 124 images
I get 4 sequences burned in:
1-82
1-5
1-25
1-9
This is almost certainly not due to scene detection (neither the
filtering framework or drawtext filter has any provision for that).
What this is, is the filtergraph being reinitialized when some property
of the input changes - for video/images, the candidates are resolution
or the pixel format.
That can be suppressed,
ffmpeg.exe -y -framerate 10 -reinit_filter 0 -i final-%d.png -vf
"scale,format=rgb24,drawtext=fontfile='C\:/WINDOWS/fonts/arialbd.ttf':text=%
{frame_num}:start_number=1:fontcolor=black:fontsize=15:x=10:y=10" -
pix_fmt rgb24 -c:v qtrle -r 10 test.mov
(scale filter prefixed since only some filters can handle changing input
without reinit). For image and capture input, -framerate is preferable.
Gyan
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