audio issue when keyframing audio strips pitch value

[mazzo23]

there is an audio issue that makes bpsrender not mixdown the audio completely when you use speed control strips and keyframe the pitch of the audio strips to match the video strip speed.

reproduce:
on the "Speed Control" strip, uncheck "Stretch to input stip length" and use "Speed factor" to keyframe the value for speed control.
copy/paste the keyframes from the "Speed Control" strip to the audio pitch value, so that the sound pitch matches the speed control.
render the video with bpsrender.

result:
bpsrender leaves the keyframed audio strips out (they are silent in the mixdown). all untouched audiostips are mixed down correctly.

workaround:
mixdown audio only with blender, and render the video w/o audio in bpsrender, then --join with bpsrender or ffmpeg

thx 4 the speedy renders! <3