Hi,
I tried to convert a 1920x1080 video to 1280x720. The resulting file had
little stutters in scenes where the camera is moving slowly but constantly.
I finally ended up with the following command to get a quality as close
to the original as possible:
ffmpeg -i movie.mkv -vf scale=-1:720 -c:v mpeg2video -q:a 0 -q:v 0 -maxrate
38800k -preset veryslow -c:a copy -scodec copy test.mkv
The video streams look very similar.
movie.mkv:
Duration: 00:25:10.24, start: 0.000000, bitrate: 13949 kb/s
Stream #0:0(eng): Video: mpeg2video (Main), yuv420p(tv), 1920x1080 [SAR 1:1
DAR 16:9], Closed Captions, max. 38800 kb/s, 29.97 fps, 29.97 tbr, 1k tbn,
59.94 tbc (default) (forced)
test.mkv:
Duration: 00:25:10.24, start: 0.000000, bitrate: 8299 kb/s
Stream #0:0(eng): Video: mpeg2video (Main), yuv420p(tv), 1280x720 [SAR 1:1
DAR 16:9], max. 38800 kb/s, 29.97 fps, 29.97 tbr, 1k tbn, 59.94 tbc (default)
(forced)
Only the bitrate is different. When I play this test.mkv with mplayer or mpv,
the little stutters are still there, but they are not with movie.mkv.
And they are not there when I play test.mkv with xine.
I also tried with "-c:v libx264 -crf 10" instead of mpeg2video, same result.
Any idea what could cause these stutters?
cu,
Frank
P.S.: my ffmpeg version:
ffmpeg version 3.0.4 Copyright (c) 2000-2016 the FFmpeg developers
built with gcc 4.8 (SUSE Linux)
configuration: --prefix=/usr --libdir=/usr/lib64 --shlibdir=/usr/lib64
--incdir=/usr/include/ffmpeg --extra-cflags='-fmessage-length=0
-grecord-gcc-switches -fstack-protector -O2 -Wall -D_FORTIFY_SOURCE=2
-funwind-tables -fasynchronous-unwind-tables -g' --optflags='-fmessage-length=0
-grecord-gcc-switches -fstack-protector -O2 -Wall -D_FORTIFY_SOURCE=2
-funwind-tables -fasynchronous-unwind-tables -g' --disable-htmlpages
--enable-pic --disable-stripping --enable-shared --disable-static
--enable-runtime-cpudetect --enable-gpl --disable-openssl --enable-avresample
--enable-libcdio --enable-gnutls --enable-ladspa --enable-libass
--enable-libbluray --enable-libcelt --enable-libcdio --enable-libdc1394
--enable-libfreetype --enable-libgsm --enable-libopenjpeg --enable-libopus
--enable-libpulse --enable-libschroedinger --enable-libspeex --enable-libtheora
--enable-libvorbis --enable-libvpx --enable-libwebp --enable-pic
--enable-pthreads --enable-vaapi --enable-vdpau --enable-libfdk
_aac --enable-nonfree --enable-libmp3lame --enable-libtwolame --enable-libx264
--enable-libx265 --enable-libxvid --enable-x11grab
libavutil 55. 17.103 / 55. 17.103
libavcodec 57. 24.102 / 57. 24.102
libavformat 57. 25.100 / 57. 25.100
libavdevice 57. 0.101 / 57. 0.101
libavfilter 6. 31.100 / 6. 31.100
libavresample 3. 0. 0 / 3. 0. 0
libswscale 4. 0.100 / 4. 0.100
libswresample 2. 0.101 / 2. 0.101
libpostproc 54. 0.100 / 54. 0.100
--
Dipl.-Inform. Frank Steiner Web: http://www.bio.ifi.lmu.de/~steiner/
Lehrstuhl f. Bioinformatik Mail: http://www.bio.ifi.lmu.de/~steiner/m/
LMU, Amalienstr. 17 Phone: +49 89 2180-4049
80333 Muenchen, Germany Fax: +49 89 2180-99-4049
* Rekursion kann man erst verstehen, wenn man Rekursion verstanden hat. *
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