XAudio2 delay with small buffer size

Question

I'm writing a video player. For audio part i'm using XAudio2. For this i have separate thread that is waiting for BufferEnd event and after this fills buffer with new data and call SubmitSourceBuffer. The problem is that XAudio2(driver or sound card) has huge delays before playing next buffer if buffer size is small (1024 bytes). I made measurements and XAudio takes up to two times long for play such chunk. (1024 bytes chunk of 48khz raw 2-channeled pcm should be played in nearly 5ms, but on my computer it's played up to 10ms). And nearly no delays if i make buffer 4kbytes or more. I need such small buffer to be able making synchronizations with video clock or external clock (like ffplay does). If i make my buffer too big then end-user will hear lot of noises in output due to synchronization stuff.

Also i have made measurements on all my functions that are decoding and synchronizing audio or anything else that could block or produce delays, they take 0 or 1 ms to execute, so they are not the problem 100%.

Does anybody know what can it be and why it's happenning? Can anyone check if he has same delay problems with small buffer?

Answer 1

I've not experienced any delay or pause using .wav files. If you are using mp3 format, it may add silence at the beginning and end of the sound during the compress operation thus causing a delay in your sound playing. See this post for more information.