mkv magic (repair and resize mkv)

I had am mkv HD film that did not work!

1st get some info:

mkvinfo -s /mnt/nfs/nas2/Movie/Fiction/Thor/video.mkv | head -5

Track 1: Video, Codec-ID: V_MPEG4/ISO/AVC (h.264-Profil: High @L4.1), Track ID für mkvmerge/mkvextract: 0, Standarddauer: 41.708ms (23.976 Bilder/Felder pro Sekunde im Falle eines Video-Tracks), Sprache: und, Pixelbreite: 1920, Pixelhöhe: 816, Anzeigebreite: 1920, Anzeigehöhe: 816

Track 2: Audio, Codec-ID: A_AC3, Track ID für mkvmerge/mkvextract: 1, Standarddauer: 32.000ms (31.250 Bilder/Felder pro Sekunde im Falle eines Video-Tracks), Sprache: und, Abtastfrequenz: 48000, Kanäle: 2

Track 3: Audio, Codec-ID: A_DTS, Track ID für mkvmerge/mkvextract: 2, Standarddauer: 10.667ms (93.750 Bilder/Felder pro Sekunde im Falle eines Video-Tracks), Sprache: und, Abtastfrequenz: 48000, Kanäle: 6

I Frame, Track 1, Zeitstempel 0 (00:00:00.000), Größe 1080, Adler 0xf822129c

I Frame, Track 2, Zeitstempel 0 (00:00:00.000), Größe 1534, Adler 0x07896a98

and extract the tracks

mkvextract tracks /mnt/nfs/nas2/Movie/Fiction/Thor/viodeo.mkv 0:mkv_video 1:mkv_audio1 2:mkv_audio2

and remerge

mkvmerge --default-duration 0:23.976fps mkv_video mkv_audio1 mkv_audio2 -o videout.mkv

did work for me

and resize:

Take the xtracted video track

ffmpeg -i mkv_video -vcodec libx264 -preset ultrafast -s 1280x544 -acodec copy video-544.h264

and remerge as before

mkvmerge --default-duration 0:23.976fps video-544.h264 mkv_audio1 mkv_audio2 -o videout-smaller.mkv

Thats it

PS Screenrecording with ffmpeg
ffmpeg -f x11grab -s wxga -r 25 -i :0.0 -sameq output.mpg
PPS copy ts to mkv (without subtitles)
ffmpeg -i Infile.ts -vcodec copy -sn -sameq -acodec copy -f matroska Outfile.mkv