Question

More specifically:
I have a sequence of 32 bit unsigned RGBA integers for pixels- e.g. 640 integers per row starting at the left pixel, 480 rows per frame starting at the top row, repeat for n frames. Is there an easy way to feed this to ffmpeg (or some other encoder) without first encoding it to a common image format?

I’m assuming ffmpeg is the best tool for me to use in this case, but I’m open to suggestions (the output video format doesn’t matter too much).

---

I know the documentation would enlighten me if I just knew the right keywords… In case I’m asking the wrong question, here’s what I’m trying to do at the highest level:

I have some Actionscript code that draws and animates on the display tree, and I’ve wrapped it in an AIR application that draws BitmapData frame-by-frame. AIR has proved to be woefully inefficient at directly encoding this output- the best I’ve managed is a few frames per second, and I need to render at least 15 fps, preferably more like 100 fps, which I get out of ffmpeg when I feed it PNG images (AIR can take 1+ seconds to encode one 640×480 png… appalling). Instead of encoding inside AIR I can send the raw byte data out to an encoder or to disk as fast as it’s rendered.

If you’re wondering why I’m using Actionscript to render an animation or why it has to be encoded quickly, don’t. Suffice it to say, the frames are computed at execution time (not stored as an animation in a .swf file, for example), I have a very large amount of video to create and limited time to do so, and using something other than Actionscript to produce the frames is not an option.

Answer 1

The solution I’ve come up with is to use x264 instead of ffmpeg.

For testing purposes, I saved frames as files: 00.bin, 01.bin, .. nn.bin, containing 640x480x4 ARGB pixel values. The command I used to verify that the approach is feasible is the following horrible hack:

cat *.bin | \
perl -e 'while (sysread(STDIN,$d,4)){print pack("N",unpack("V",$d));}' | \
x264 --demuxer raw --input-csp bgra --fps 15 --input-res 640x480 --qp 0 \
     --muxer flv -o out.flv -

The ugly perl snippet in there is a hack to swap four-byte endian order, since x265 can only take BGRA and my test files contained ARGB.

In a nutshell,

1. Actionscript renders ARGB values into ByteArray
2. swap the endian to BGRA
3. pipe it to x264: raw demuxer, bgra colorspace, specify fps/w/h/quality
4. ??
5. profit.