Player.Controls.step(-1) not work ?
NetDNA
why this method do not work ?
i want to play a single frame by step function.
howerver Player.Controls.step(1) works ，how does it work ?
The file played is a local mpg file .
msn messenger: net__ at msn dot com
Neil Smith [MVP Digital Media]
>Player.Controls.step(-1) not work ?
>
>why this method do not work ?
>i want to play a single frame by step function.
>
>howerver Player.Controls.step(1) works ，how does it work ?
>
>The file played is a local mpg file .
Some files don't support seeking in that way (they have to be indexed
files, and MPEG can't be indexed for WMP). I'm prepared to bet it
works fine with a WMV or ASF file - am I right ?
This page details the method isAvailable("action") which you need to
use to test if you can take the specified navigation with a chosen
(and loaded) media file :
http://windowssdk.msdn.microsoft.com/en-us/library/ms739494.aspx
Cheers - Neil
------------------------------------------------
Digital Media MVP : 2004-2006
http://mvp.support.microsoft.com/mvpfaqs
Alessandro Angeli [MVP::DS/MF]
> Player.Controls.step(-1) not work ?
>
> why this method do not work ?
> i want to play a single frame by step function.
>
> howerver Player.Controls.step(1) works ，how does it work
> ?
> The file played is a local mpg file .
That's the expected behavior. With temporally compressed
files (e.g. MPEG) it's easy to step forwards (the format is
designed for forward playback) but very hard to step
backwards. The stock MPEG parsers included in Windows and
any other third-party ones I know of do not support backward
frame stepping, so WMP can not step backwards when using
those parsers.
--
// Alessandro Angeli
// MVP :: DirectShow / MediaFoundation
// a dot angeli at psynet dot net
AUGE_OHR
> Player.Controls.step(-1) not work ?
try :
nPosi = oPlayer.Controls.CurrentPosition
IF nPosi <= 0.0
oPlayer.Controls.CurrentPosition = 0.0
ELSE
oPlayer.Controls.CurrentPosition = nPosi-(0.04) // PAL 25f/s
ENDIF
greetings by OHR
Jimmy
NetDNA
I'll support this group forever
"NetDNA" <ne...@msn.com> wrote in message
news:OHioXgOp...@TK2MSFTNGP03.phx.gbl...
Robert
"Alessandro Angeli [MVP::DS/MF]" <nob...@nowhere.in.the.net> wrote in
message news:eAei%23JRpG...@TK2MSFTNGP03.phx.gbl...
> NetDNA wrote:
>
>> Player.Controls.step(-1) not work ?
>>
>> why this method do not work ?
>> i want to play a single frame by step function.
>>
>> howerver Player.Controls.step(1) works ，how does it work
>> ?
>> The file played is a local mpg file .
>
> That's the expected behavior. With temporally compressed files (e.g. MPEG)
> it's easy to step forwards (the format is designed for forward playback)
> but very hard to step backwards. The stock MPEG parsers included in
> Windows and any other third-party ones I know of do not support backward
> frame stepping, so WMP can not step backwards when using those parsers.
I have been doing some DirectShow stuff lately, and in the forums of
DirectShow.Net on sourceforge
there are several messages claiming Elecard.Com codecs do support the
correct time stamps to
allow seeking in Mpeg's.
HTH
Alessandro Angeli [MVP::DS/MF]
> I have been doing some DirectShow stuff lately, and in
> the forums of DirectShow.Net on sourceforge
> there are several messages claiming Elecard.Com codecs do
> support the correct time stamps to
> allow seeking in Mpeg's.
The Elecard MPEG parser is probably the best one, but all
MPEG parsers support seeking, however time-based seeking on
a VBR file is not reliable if you want it to also be
frame-precise, because timestamps in an MPEG stream may not
be consecutive.
Alessandro Angeli [MVP::DS/MF]
> nPosi = oPlayer.Controls.CurrentPosition
> IF nPosi <= 0.0
> oPlayer.Controls.CurrentPosition = 0.0
> ELSE
> oPlayer.Controls.CurrentPosition = nPosi-(0.04) // PAL
> 25f/s ENDIF
Setting the currentPosition means seeking in the file and,
as discussed, it is not a reliable method.
Robert
> support seeking, however time-based seeking on a VBR file is not reliable
> if you want it to also be frame-precise, because timestamps in an MPEG
> stream may not be consecutive.
My project is viewing security camera videos. The clients have a variety of
different cameras.
Since VBR's are quite cpu intensive to make, I would assume that most
cameras would not have
the expensive firmware for this type of encoding.
The general requirements are marking segments, viewing them multiple times,
and capturing still images.
Frame accurate seeking is highly desired.
Is this feasible? Currently I am playing the videos and capturing the still
images, the seeking part is next..