[Discuss-gnuradio] File Sink & Buffering

[Ryan Pape]

Currently in response to a message in a message queue, I am opening a file sink which is connected a bit stream of about 10K/sec (one byte per bit).  I keep this file sink open until I receive another message in the queue to stop the capture, at which time I close() it.

Ideally, the capture would start immediately upon the triggering event, but there is some latency with the overheard of the message enqueue/dequeue/file open which I believe is causing me to miss data.  The first bits missing are part of frame sync, which is causing me to throw out the rest in some instances.

Is there a way with the current existing blocks to build a buffer (say 10K - or about 1 second), such that once I open the sink I am essentially looking back in time to capture the bits that happened AFTER my triggering event but BEFORE I processed the message from the queue?   I know there is a built in buffer block, but I would think ideally I want to buffer and then drain the buffer as fast as possible (potentially faster than new samples are incoming?)

Or, would it be best to build a custom file sink block with this behavior integrated into it?