[vlc] Re: Dump streamed data

[Benjamin PRACHT]

On Fri, Apr 09, 2004, Philippe De Neve wrote :

> Hi,
> 
> I want to stream a file (I used MPEG-1 .m1v and MPEG-4 .mp4) from VLC to VLC
> using UDP or RTP. This works fine. The player VLC shows the clip although
> the first fraction of second the display is ugly (green) but fastly
> recovers. No big problem so far.

That's related to the  fact that VLC has to wait for  a complete I image
before it can decode a proper image. That issue is related to the nature
of yout MPEG4 stream, and cannot be avoided.

> When I now want to dump this video clip to an output file I can choose
> between  'raw data'  or not.  When I  do NOT  use 'dump  as raw  data'
> a  file  is  contructed  but  it's  smaller  than  the  original  file
> (1100219<->1055432 bytes). So some bytes where forgotten?The resulting
> file is unplayable  so I checked the file binary  with ultraedit which
> showed me that some (about 300)  "ff" bytes and some other stuff where
> appended  at the  beginning of  the  file .They  do NOT  exist in  the
> originating file.  There's probably  a relation with  the fact  VLC is
> displaying the first 5 frames (or so) green.
>

That fact the file  size is not the same than the  original one could be
explained by you  using a different muxer.  Having a bunch of  FF at the
beginnig of  a file could be  normal with some muxers,  but shouldn't be
related to the "green video" issue.  When you say you cannot re-read the
stream, do you mean that VLC is unable to read it, or another software ?

> Now  I  tried  to  dump  the  file as  "raw  data"  which  results  in
> ....nothing. No file gets created and no data gets dumped?

Strange.  No file  is generates,  or it  is deleted  at the  end of  the
playback ? Copuld you send us the logs of this part (view->messages)

> This dumping capability is important for me (I want to measure quality
> afterwards).  Can anybody  tell me  if this  is a  bug or  am I  doing
> something very wrong?

Well, since VLC doesn't re encode the stream if not told to, the quality
the resulting  stream will  be the  same as  the original  one, excepted
network related issues ;-)

> 
> 
> wfr, Philipe De Neve
> 
> 
> Some computer information:
> 
> 
> Operating System   System Model
> Windows XP Professional Service Pack 1 (build 2600)   No details available
> 
> Processor
> 1,80 gigahertz AMD Athlon XP
> 128 kilobyte primary memory cache
> 256 kilobyte secondary memory cache   Board: K7VT2 2.00
> 
> Main Circuit Board
> Bus Clock: 133 megahertz
> BIOS: American Megatrends Inc. P1.20 12/10/2002
> Drives   Memory Modules c,d
> 39,99 Gigabytes Usable Hard Drive Capacity
> 14,63 Gigabytes Hard Drive Free Space
> 
> SAMSUNG CD-ROM SC-152A
> 3.5" format removeable media [Floppy drive]
> 
> WDC WD400BB-60DGA0 [Hard drive] (40,02 GB) -- drive 0, s/n WD-WCADK3849758,
> rev 05.03E05, SMART Status: Healthy   512 Megabytes Installed Memory
> 
> Slot '0' has 512 MB
> Slot '1' is Empty
> Slot '2' is Empty
> Slot '3' is Empty
>   Local Drive Volumes
> 
> c: (on drive 0) 15,72 GB 3,16 GB free
> e: (on drive 0) 10,48 GB 4,53 GB free
> f: (on drive 0) 4,20 GB 2,21 GB free
> g: (on drive 0) 9,60 GB 4,73 GB free
> 
> 
> 
> 
> 
> *********************************************************
>   ir. De Neve Philippe
>   Ghent University
>   Department of Information Technology (INTEC)
>   Sint-Pietersnieuwstraat 41
>   B-9000 Gent (Belgium)
>   tel. :       +32 9 264 99 57
>   e-mail :  philippe.deneve at intec.UGent.be
> *********************************************************
> 
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-- 
$(echo "BigBen")

Oui je quote, et alors ?

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