[vlc] Re: Mac OS X vlc video artifacts question

[Dave Schroeder]

VLC 0.8.4a will not play a 19Mbps MPEG-2 HD source stream (multicast  
via Internet2) for me well at all on a dual 2.0GHz G5 or a quad  
2.5GHz G5, both running Mac OS X 10.4.5 and doing nothing else. The  
video has *heavy* multicolored MPEG artifacts or "blocks", and the  
audio portion of the stream usually dies after a few seconds. (Our  
network is also for sure not the issue.) I have noticed that the  
higher powered the machine, the less problem the artifacting is on  
higher bandwidth streams; e.g., the quad 2.5 G5 has slightly less  
problems than the dual 2.0 G5.

The same stream plays perfectly on Windows machines with relatively  
modest specs. (I know that VLC is open source and some people might  
have the "well, find out what the problem is and fix it" attitude,  
but I'm afraid I don't have that capability here, so I'm just asking  
if other people have seen these problems, or if anyone knows where  
they might be coming from and if/how they might be fixed. I asked in  
the VLC irc channel once, and a couple of people there made it sound  
like it was a well-known issue with the Mac version of VLC, but  
didn't have any idea if bugs were open on it, if fixes were planned,  
or anything like that.)

I would be more than happy to try to take pictures or screenshots, or  
perform any other work necessary in determining what the problem is.  
For the record, I know it's not "user error", a problem with the  
source, or a problem with our network (since Windows machines on the  
same network handle the same multicast source stream perfectly and  
consistently every time).

Regards,

Dave Schroeder           |    University of Wisconsin - Madison
Senior Systems Engineer  |   Division of Information Technology
Email: das at doit.wisc.edu |                  Systems Engineering
Web:   das.doit.wisc.edu | B263 Computer Science and Statistics
Cell:  +1 608 444-5672   |              1210 West Dayton Street
Phone: +1 608 265-4737   |        Madison, Wisconsin 53706-1685


On Mar 2, 2006, at 8:15 PM, Armando Stettner wrote:

> VLC would not display at all well an MPEG2 HD stream (~19.1 Mbps  
> measured) on my 1.67 GHz PowerPC G4 Aluminum laptop.   I ran VLC  
> with the same streams, sources, and network on a higher end Mac  
> (Dual 2.3 HJz PowerPC G5) and it played like a champ.  I do not  
> thikn I saw any artifacting.  I'm not saying that you need all that  
> power.
>
> Don't know if this helps or not....
>
>    armando
>
>
>
> Begin forwarded message:
>
>> From: "Dave Schroeder" <das at doit.wisc.edu>
>> Date: March 2, 2006 5:26:23 PM PST
>> To: <vlc at videolan.org>
>> Subject: [vlc] Mac OS X vlc video artifacts question
>> Reply-To: <vlc at videolan.org>
>>
>> Hello,
>>
>> Does anyway know about the issue with the Mac OS X version of vlc  
>> showing serious MPEG artifacts or pixellation with particularly  
>> high bandwidth network streams? I've seen in on a large number of  
>> Mac OS X machines, but the same streams are perfect on, for  
>> example, the Windows of vlc.
>>
>> We're looking at using vlc for a fairly large transcoding  
>> operation (4Mbps MPEG-2 TS to MPEG-4). Does anyone know what the  
>> stem of this problem is (or even what I'm talking about), and if  
>> there is any current work on fixing it?
>>
>> Thanks very much for your help!
>>
>> Regards,
>>
>> Dave Schroeder           |    University of Wisconsin - Madison
>> Senior Systems Engineer  |   Division of Information Technology
>> Email: das at doit.wisc.edu |                  Systems Engineering
>> Web:   das.doit.wisc.edu | B263 Computer Science and Statistics
>> Cell:  +1 608 444-5672   |              1210 West Dayton Street
>> Phone: +1 608 265-4737   |        Madison, Wisconsin 53706-1685
>
> -- 
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