Conversie WMV multi-track in SBS

Salut,

M-a rugat cineva sa-l ajut cu niste fisiere video 3D.
Ele arata cam asa:
[wmv3 @ 0x19b4740] Extra data: 8 bits left, value: 0
[wmv3 @ 0x19b4ee0] Extra data: 8 bits left, value: 0
Guessed Channel Layout for  Input Stream #0.2 : stereo
Input #0, asf, from 'movie1.wmv':
  Metadata:
    WMFSDKVersion   : 12.0.7600.16385
    WMFSDKNeeded    : 0.0.0.0000
    StereoscopicLayout: DualStream
    Stereoscopic    : 1
    IsVBR    : 0
    DeviceConformanceTemplate: MP@HL
  Duration: 00:30:21.37, start: 0.000000, bitrate: 20171 kb/s
    Stream #0:0: Video: wmv3 (Main) (WMV3 / 0x33564D57), yuv420p, 1920x1080, 10000 kb/s, 25 fps, 25 tbr, 1k tbn, 1k tbc
    Stream #0:1: Video: wmv3 (Main) (WMV3 / 0x33564D57), yuv420p, 1920x1080, 10000 kb/s, 25 fps, 25 tbr, 1k tbn, 1k tbc
    Stream #0:2: Audio: wmav2 (a[1][0][0] / 0x0161), 48000 Hz, 2 channels, fltp, 128 kb/s

Sunt 2 stream-uri, stanga si dreapta.

Cum fac sa ajung la un singur stream video, side-by-side, tot 1920x1080?
Am aflat cum pot extrage stream-urile in fisiere separate, eventual cum sa le convertesc in MKV, dar de acolo pauza.

ffmpeg -i movie1.wmv -map 0:0 -map 0:2  -vcodec copy -acodec copy movie1_left.wmv
ffmpeg -i movie1.wmv -map 0:1  -vcodec copy movie1_right.wmv
ffmpeg -i movie1_left.wmv movie1_left.mkv
ffmpeg -i movie1_right.wmv movie1_right.mkv

Sunt vreo 50 de fisiere si 200GB, am nevoie de ceva command-line, e exclus sa stau sa le trec prin virtual dub/avi synth

Merci!