Andrea,
I must be doing something wrong? I loaded a small 1.5 minute video and rendered it using DPX.dpx and it only created a single video file that was all black when I used ffplay to play it. Mediainfo shows:
General
Complete name : junk4.dpx
Format : DPX
Format version : Version 1.0
File size : 497 KiB
Writing library : Lavc58.134.100
Image
Format : DPX
Format version : Version 1.0
Format_Compression : Raw
Format settings : Little / Packed
Width : 352 pixels
Height : 240 pixels
Display aspect ratio : 3:2
Color space : RGB
Bit depth : 16 bits
Compression mode : Lossless
Stream size : 497 KiB (100%)
Writing library : Lavc58.134.100
Transfer characteristics : Linear