Re: Length of avi is incorrect when recording at low frates?
- From: "Thore B. Karlsen [DShow MVP]" <sid@xxxxxxxx>
- Date: Mon, 10 Sep 2007 09:56:59 -0500
On Mon, 10 Sep 2007 07:12:03 -0700, mash <Mashman@xxxxxxxxxxxxxxxx>
wrote:
Hello all,
I'm not a video expert so this may be a simple question for some.
I have an application that simply records video to a file while rendering
the video using a renderer as well. Before recording I query the video
capture source for max/min frame rates and allow the user to set a frame rate
within these limits.
For most cameras that I've used this works fine. But I was recently testing
using a Philips SPC 900NC camera and I set the frame rate to 10 fps. I then
recorded for about 10 seconds but the resulting avi is about 28 seconds. The
frame rate of the .avi is 10fps but the number of frames in the file (queried
using IMediaSeeking) is 280 frames.
If I change the frame rate to, say, 30fps, the length of the file will be
correct (if I record for 10 seconds the length of the file is 10 seconds).
I tested using graph edit and I got the same results (so it doesn't seem to
be something that I'm doing wrong?). The camera's propery pages allow me to
set the frame rate from 5fps to 90 fps so it seems that I'm within the frame
rate limits.
This discrepancy in what I expect the length of the file to be and what it
actually is gets worse as I decrease the frame rate.
Another thing that I notice is that if I look at the file properties in
Windows explorer the datarate of the file recorded at 10fps is 1132kbps.
whereas the datarate of the file recorded at 30fps isn't even displayed.
Why would recording at different frame rates affect the length of the video
file? And is there any way to work around this?
It sounds like there is some problem with the driver, because I can't
think of a good reason why you should be seeing what you're seeing. If
you set the frame rate to a lower value and just render the video to
the display instead of writing it to disk, does it look like a higher
frame rate than it should be?
--
Be seeing you.
.
- Prev by Date: Re: Play MPEG from byte array?
- Next by Date: Re: link errors building VMRPlayer
- Previous by thread: Re: how to detect * object left active issue in dll~~
- Next by thread: advise time
- Index(es):
Relevant Pages
|
