I am interested in scaling a video to a larger size without applying any filter or anything. The output video should look very pixelated. How do I do this in FFMPEG?
On the suggestion of Ronald S. Bultje, I am using the neighbor flag. I have also decided to use the rawvideo codec to avoid compression.
The current command I am running is
ffmpeg -i vid.avi -s 800x800 -sws_flags neighbor -sws_dither none -vcodec rawvideo vid2.avi
The command line output of that command is
ffmpeg version 2.7 Copyright (c) 2000-2015 the FFmpeg developers
built with Apple LLVM version 6.1.0 (clang-602.0.53) (based on LLVM 3.6.0svn)
configuration: --prefix=/opt/local --enable-swscale --enable-avfilter --enable-avresample --enable-libmp3lame --enable-libvorbis --enable-libopus --enable-libtheora --enable-libschroedinger --enable-libopenjpeg --enable-libmodplug --enable-libvpx --enable-libspeex --enable-libass --enable-libbluray --enable-lzma --enable-gnutls --enable-fontconfig --enable-libfreetype --enable-libfribidi --disable-indev=jack --disable-outdev=xv --mandir=/opt/local/share/man --enable-shared --enable-pthreads --cc=/usr/bin/clang --enable-vda --arch=x86_64 --enable-yasm --enable-gpl --enable-postproc --enable-libx264 --enable-libxvid
libavutil 54. 27.100 / 54. 27.100
libavcodec 56. 41.100 / 56. 41.100
libavformat 56. 36.100 / 56. 36.100
libavdevice 56. 4.100 / 56. 4.100
libavfilter 5. 16.101 / 5. 16.101
libavresample 2. 1. 0 / 2. 1. 0
libswscale 3. 1.101 / 3. 1.101
libswresample 1. 2.100 / 1. 2.100
libpostproc 53. 3.100 / 53. 3.100
Input #0, avi, from 'vid.avi':
Duration: 00:00:25.00, start: 0.000000, bitrate: 226 kb/s
Stream #0:0: Video: rawvideo, pal8, 80x80, 206 kb/s, 4 fps, 4 tbr, 4 tbn, 4 tbc
File 'vid2.avi' already exists. Overwrite ? [y/N] y
Output #0, avi, to 'vid2.avi':
Metadata:
ISFT : Lavf56.36.100
Stream #0:0: Video: rawvideo, pal8, 800x800, q=2-31, 200 kb/s, 4 fps, 4 tbn, 4 tbc
Metadata:
encoder : Lavc56.41.100 rawvideo
Stream mapping:
Stream #0:0 -> #0:0 (rawvideo (native) -> rawvideo (native))
Press [q] to stop, [?] for help
frame= 100 fps=0.0 q=0.0 Lsize= 62608kB time=00:00:25.00 bitrate=20515.4kbits/s
video:62600kB audio:0kB subtitle:0kB other streams:0kB global headers:0kB muxing overhead: 0.012614%
ffmpeg -i infile -vf scale=WIDTH:HEIGHT:flags=neighbor outfile
or
ffmpeg -i infile -s WIDTHxHEIGHT -sws_flags neighbor outfile
The critical part here is flags or -sws_flags, which selects the filter (and other scaling-related flags). The default filter value is bicublin (IIRC), which means a bicubic luma and bilinear chroma filter. Nearest-neighbour will do what you're asking for.
See scaler options for a list other scaling algorithms.