I'd like to ask the same question as Philip Dow, which is
essentially: When performing just compression - is it necessary to
also perform the ICM decompression stage, and have this feed the
compression stage?
Put another way, does the decompression stage incur much in the way
of overhead? (At present, Shark tells me it does - approx 26% CPU
for apple intermediate codec). Shark seems to show that most time
is spent in decompression: icm_Copy_2vuy_32ARGB.
Anyway, at this stage I don't want to complicate my question by
asking two things at one, so I'll just leave the Q as...
Is is possible to remove the decompression code, and use purely ICM
compression to achieve the same thing?
Kind Regards,
Neil Clayton
On 9/01/2006, at 5:16 PM, Philip Dow wrote:
Oh man oh man oh man! Please forgive the slew of posts, but I've
been working like a madman on this thing for the last two days and
now, it actually works! I have a cocoa object that I can plug into
any cocoa application which provides one click video recording and
compression to h264 aac. Thanks much for the pointers Brad.
Of course, I have one more question: I am basing the callback I
provide to SGSetDataProc on the code found in
CaptureAndCompressIPBMovie. The callback there uses a decompression
session and a compression session to write the video data to the
video track. The decompression session adds the time to the video
and displays it in a window and only afterwards has the compression
session encode a frame.
I do not need to add any text to the movie and I do not need to
display it in a window, as the SGVideo object is already taking
care of this for me. How can I skip this unnecessary step? I feel
like I should be able to call ICMCompressionSessionEncodeFrame
directly from the callback associated with SGSetDataProc, but the
variables available to that callback do not match those required by
ICMCompressionSessionEncodeFrame, in particular a pixel buffer. Is
there a way to avoid this seemingly unnecessary step?
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