Feature request: Support for multiple codecs and resolutions using concat demuxer

[Johan Lindgren]

Summary of the bug: concat fails when splicing two videos of different codecs
How to reproduce:
Have 2 videofiles, movie1.mov with mpeg4 video-codec and movie2.avi with h264 video-codec
Create a file (clips.txt) with following 2 lines:

file 'movie1.mov'
file 'movie2.avi'

After the command below, watch resulting video after the splice.

ffmpeg -f concat -i clips.txt -vcodec libx264 -preset ultrafast -crf 24 -pix_fmt yuv420p -s 1920x1080 -aspect 16:9 -acodec aac -strict experimental -b:a 128k -ar 44100 -ac 2 Final.mov

ffmpeg version 2.1.git Copyright (c) 2000-2014 the FFmpeg developers
  built on Mar  1 2014 16:09:23 with gcc 4.6 (Ubuntu/Linaro 4.6.3-1ubuntu5)
  configuration: --prefix=/home/johan/ffmpeg_build --extra-cflags=-I/home/johan/ffmpeg_build/include --extra-ldflags=-L/home/johan/ffmpeg_build/lib --bindir=/home/johan/bin --extra-libs=-ldl --enable-gpl --enable-libass --enable-libfdk-aac --enable-libmp3lame --enable-libopus --enable-libtheora --enable-libvorbis --enable-libvpx --enable-libx264 --enable-nonfree
  libavutil      52. 66.100 / 52. 66.100
  libavcodec     55. 52.102 / 55. 52.102
  libavformat    55. 33.100 / 55. 33.100
  libavdevice    55. 10.100 / 55. 10.100
  libavfilter     4.  2.100 /  4.  2.100
  libswscale      2.  5.101 /  2.  5.101
  libswresample   0. 18.100 /  0. 18.100
  libpostproc    52.  3.100 / 52.  3.100

[Carl Eugen Hoyos]

FFmpeg does not even support VC-1 and WMV3 (two very similar codecs) in the same stream, see ticket #655. Supporting two very different codecs (like ASP and AVC) in one video stream seems impossible.

Please use the concat filter.