Hello,
I'm having difficulties with alpha channel in an exporter. Symptoms - no alpha channel is given to my exporter by Premiere Pro when using source with alpha channel. I created a sample test video that has rows of (red pixel, green pixel, blue pixel, alpha pixel). So, while examining bits in the memory, I always see 0xff for alpha component (i.e, red pixel looks like 0xff 0x00 0x00 0xff, green pixel looks like 0x00 0xff 0x00 0xff, blue pixel looks like 0x00 0x00 0xff 0xff, and alpha pixel looks like 0x00 0x00 0x00 0xff), which looks to me like no alpha channel given in the frame. I request frames in BGRA_4444_8u pixel format. Correct me if I'm mistaken, but shouldn't that color format give me alpha component if source has alpha? I thought "ok, may be sequence or project settings have setting that i'm not enabling to preserve alpha", but as I found out, Premiere Pro preserves alpha unless explicitly told not to preserve by user. SDK Exporter sample project description mentions support for uncompressed 8 bit RGB with or without alpha. Does that mean that Premiere Pro should give frames with alpha channel if source had it? I looked at how sample exporter requests frames from Premiere Pro and only color format-specific info is custom 'sdk' color format, unless I overlooked something.
Thank you,
Petro