Slow decoding with avcodec_send_packet?

I noticed that FFmpeg wasm decoding an 1080p 30fps video can only achieve around 25fps on my MacBook Pro (2GHz 4-core i5). However native FFmpeg binary or regular video player can easily achieve >60fps.

I timed different functions in the decoding loop - it turns out calling `avcodec_send_packet` in FFmpeg takes about 40ms (which counts for about 25fps). I suspect this core function being slow is because FFmpeg wasm disables most hardware acceleration and it's single threaded by default?

Just want to check if this is a known issue and if there's existing solutions for boosting the performance. Many thanks!