[vlc-devel] VLC's performance on SMP system

[Kaarlo Räihä]

libavcodec used in VLC Windows builds doesn't include multithreaded H.264 decoding. Changes are gonna happen when multithreaded decoding is merged to libavcodec stable branch. (you can naturally try to build multithreaded one for Windows from unstable branches like ffdshow does)


xxcv kirjoitti 29.05.2009 kello 14:43:
>     Hello,
> 
> Regarding the VLC media player's playback ability on Windows SMP system.
> Information displayed by MediaInfo:
> Video
> /ID :/ 	2
> /Format :/ 	AVC
> /Format/Info :/ 	Advanced Video Codec
> /Format profile :/ 	High at L4.1
> /Format settings, CABAC :/ 	Yes
> /Format settings, ReFrames :/ 	4 frames
> /Codec ID :/ 	avc1
> /Codec ID/Info :/ 	Advanced Video Coding
> /Duration :/ 	9mn 35s
> /Bit rate mode :/ 	Variable
> /Bit rate :/ 	9 213 Kbps
> /Maximum bit rate :/ 	20.6 Mbps
> /Width :/ 	1 280 pixels
> /Height :/ 	720 pixels
> /Display aspect ratio :/ 	16/9
> /Frame rate mode :/ 	Constant
> /Frame rate :/ 	59.940 fps
> /Resolution :/ 	24 bits
> /Colorimetry :/ 	4:2:0
> /Scan type :/ 	Progressive
> /Bits/(Pixel*Frame) :/ 	0.167
> /Stream size :/ 	632 MiB (97%)
> /Writing library :/ 	x264 core 65 r1057M 5f8a149
> /Encoding settings :/ 	cabac=1 / ref=4 / deblock=1:-1:-1 / 
> analyse=0x3:0x113 / me=umh / subme=7 / psy_rd=1.0:0.0 / mixed_ref=1 / 
> me_range=16 / chroma_me=1 / trellis=2 / 8x8dct=1 / cqm=0 / 
> deadzone=21,11 / chroma_qp_offset=-2 / threads=3 / nr=0 / decimate=1 / 
> mbaff=0 / bframes=3 / b_pyramid=0 / b_adapt=2 / b_bias=0 / direct=3 / 
> wpredb=1 / keyint=250 / keyint_min=25 / scenecut=40(pre) / rc=crf / 
> crf=22.0 / qcomp=0.60 / qpmin=10 / qpmax=51 / qpstep=4 / 
> vbv_maxrate=50000 / vbv_bufsize=50000 / ip_ratio=1.40 / pb_ratio=1.30 / 
> aq=1:1.00
> /Encoded date :/ 	UTC 2009-05-24 10:15:50
> /Tagged date :/ 	UTC 2009-05-24 10:15:58
> 
> 
> Audio
> /ID :/ 	1
> /Format :/ 	AAC
> /Format/Info :/ 	Advanced Audio Codec
> /Format version :/ 	Version 4
> /Format profile :/ 	LC
> /Format settings, SBR :/ 	No
> /Codec ID :/ 	40
> /Duration :/ 	9mn 34s
> /Bit rate mode :/ 	Variable
> /Bit rate :/ 	253 Kbps
> /Maximum bit rate :/ 	260 Kbps
> /Channel(s) :/ 	2 channels
> /Channel positions :/ 	L R
> /Sampling rate :/ 	48.0 KHz
> /Resolution :/ 	16 bits
> /Stream size :/ 	17.3 MiB (3%)
> /Encoded date :/ 	UTC 2009-05-24 10:15:50
> /Tagged date :/ 	UTC 2009-05-24 10:15:58
> 
> VLC-1.0.0-RC2 failed playback of such file smoothly, video freezes 
> throughout the entire clip
> although it workaround temporarily by setting "skip the loop filter for 
> H.264 decoding" to "Non-ref"
> then video stuttering effects are reduced.
> However, this isn't the case in "Windows Media Player 11.0" using 
> ffdshow <http://sourceforge.net/projects/ffdshow-tryout> where the 
> playback is
> smooth and is in synchronization.
> Video stuttering effects occurs when processor resources are still 
> available.
> cf. attached is an image, during the same interval of 1 minute 
> processor* usage graph.
> * AMD Athlon^(TM) X2 Dual-Core
> 


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