2005-08-15, 06:08 PM
Hi,
I have extended comskip with sound processing.
To do this I hacked the mpeg2 audio decoder from libavcodec into the ps demux of libmpeg2. And yes, it may have been easier to use libavcodec also for the video part but libavcodec is only compilable with gcc and I am using vc++ and I could not find a libavcodec.lib readily build.
Now I have a strange "problem"
I use a test stream with interlaced video of 25fps and stereo sound with 48khz samplerate
When I do the math then I should use samplerate*2(stereo)/fps samples per "audio frame" to match the timing of a video frame
However this gives me an audio "framerate" that is exactly 2/3 of the video frame rate.
When I multiply the calculated samples per frame with 2/3 then audio and video match exactly. (comskip is now indeed able to discard the black frames that have sound)
Where do I make a mistake in my calculations????????
Is there anyone that can upload a short (200 MByte) NTSC recording to my ftp server so I can test the NTSC framerate?
Preferrably with show with logo, then commercials, and then again show with logo
I have extended comskip with sound processing.
To do this I hacked the mpeg2 audio decoder from libavcodec into the ps demux of libmpeg2. And yes, it may have been easier to use libavcodec also for the video part but libavcodec is only compilable with gcc and I am using vc++ and I could not find a libavcodec.lib readily build.
Now I have a strange "problem"
I use a test stream with interlaced video of 25fps and stereo sound with 48khz samplerate
When I do the math then I should use samplerate*2(stereo)/fps samples per "audio frame" to match the timing of a video frame
However this gives me an audio "framerate" that is exactly 2/3 of the video frame rate.
When I multiply the calculated samples per frame with 2/3 then audio and video match exactly. (comskip is now indeed able to discard the black frames that have sound)
Where do I make a mistake in my calculations????????
Is there anyone that can upload a short (200 MByte) NTSC recording to my ftp server so I can test the NTSC framerate?
Preferrably with show with logo, then commercials, and then again show with logo
P4 3GHz 1GB, 250GB, nVidia dualTV, GBPVR 1.3.11, XP
Support Comskip, visit the forum and donate at http://www.comskip.org/
Support Comskip, visit the forum and donate at http://www.comskip.org/
