Pulseaudio and H264/AVCHD video playback

[Luke Kuhn]

While we are on the subject of background processes that are resource hogs, Pulseaudio is in my experience among the worst offenders. My intel Atom netbook with pulseaudio running would not keep up with the framerate of H264 video in 360p, 30fps  compressed using avidemux to 800bps, on a 32 bit version of the OS. With icewm replacing unity or gnome-shell it almost could but not quite. Shut pulseaudio down (you have to make the binary non-executable or it will restart!) and it would almost but not quite handle 720p at 25 fps at 2000 bps, and in icewm only lag about 1 second out of a 4 minute video at that rate. With the 64 bit I now use and no pulseaudio, it will play that 720p/25fps with only about 50% CPU utilization, but still bog down at 30fps, again in Icewm because memory controller bandwidth is an ugly problem with any 1 channel RAM/video in northbridge/memory controller in CPU setup.
That's not too big a deal for Ubuntustudio running on power desktops, although a totally standard install of Ubuntu in a netbook should not stutter on a standard Youtube or Liveleak video! Maybe with 64 bit those will now keep up, though I have not tested Pulseaudio in 64 bit.
What is a big deal is that (again in 32 bit tests) if I ran pulseaudio on an AMD Phenom II x4 at 3.8 GHZ, I would get severe slideshowing when trying to play back AVCHD files from my video camera! This was true in the original .MTS container, in the MP4 container from ffmpeg that got buggy with these streams in Kdenlive last summer, or in the .flv containers from ffmpeg that fixed the seek bugs in Kdenlive for me. If Pulseaudio was running, I could not play back my raw clips in mplayer or totem-gstreamer. Again, shut down (and keep shut down) or remove Pulseaudio and the clips play just fine in all of my video players!
The only thing is, some computers out there have buggy soundcards so far as  running ALSA directly is concerned. No problem with the onboard sound on my desktops (or they would get dedicated soundcards) but laptops of any kind are another story. On the Acer netbook, the soundcard cannot accept a mono input, so to play a mono file in Audacious requires connecting it to Jack if not running Pulseaudio.
It sounds to me like Pulseaudio needs an entirely new backend from scratch. 		 	   		  
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