[MPlayer-users] Re: Can't play DV but can play mpeg2(DVD). Is this expected behavior
kichigai at comcast.net
Wed Dec 15 02:20:25 CET 2004
> On Tue, Dec 14, 2004 at 02:09:10AM -0500, Michael Waters wrote:
>> On Tue, 14 Dec 2004 13:37 +1300, Phil Bertram wrote:
>>> I have a 850mhz Duron, 384mb ram, S3 Trio 3D/2X 8mb AGP card.
>>> (hdparm -tT
>>> reports 18mb/s)
>>> I can not play DV without significant framedropping. (used win32
>>> codecs as
>>> well as ffmpegs).
>>> However if I encode the same footage to mpeg2 using mjpegtools it
>>> will play
>>> well. (No scaling, just deinterlacing).
>>> Is this normal ?
>>> I imagine that the decoding of the mpeg2 would be more CPU intensive
>>> than DV.
>> I don't know the technical reasons but DV takes a lot more power to
>> than dvd on my machine as well. On an athlon xp 2800 (2088 mhz) with
>> matrox g400 using xmga, playing a 720x480 ntsc dv file with qdv, ffdv,
>> or libdv, cpu usage hovers just under 30% according to gkrellm.
>> a 1.33:1 dvd, cpu usage is sporadic and under 15%.
> DV has horrible compression, and therefore it's also slow. The main
> factors in decoding, from my experience, are cache thrashing and
> bitstream parsing, and these both go way up at very high bitrates.
But this begs the question: why is it that some programs can manage
playing DV video without any problems?
Now, I have a 1GHz G4, and I experience the same problems as Phil up
there, using MPlayer that is. However, if I throw the stream into a
different program, say QuickTime, I get it to play probably as smoothly
as Michael. And it's not just QuickTime or this machine that's doing
it. The video editing software I used to use on my PC (500 MHz Pentium
III) could manage a full speed DV preview stream (Provided there were
no effects it had to render).
So why is it that MPlayer has this problem, yet other programs can get
away with it, and why can't MPlayer pull off the same tricks?
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