Screen freezes when scrolling timeline with audio waveform

Skedton · Post by **Skedton** » Sun Mar 30, 2008 3:42 am

With MSP7, When I scroll the timeline with audio track in waveform mode, the screen freezes for a long time (mintuess) but not in the filename mode. This happens when I was using a P4 with 1 Gb ram. Now I am using a duro core with 2 GB ram and things are the same. Otherwise MSP7 is working very satisfactorily. Any Ideas?

Thanks!

Devil · Post by **Devil** » Sun Mar 30, 2008 8:00 am

It is obvious that to convert a stretch of video to appear correctly takes a lot of resources and audio is secondary to video. If you are in waveform mode, then you are adding a lot of extra detail for your GUI processor to cope with.

Gorf · Post by **Gorf** » Sun Mar 30, 2008 2:51 pm

That's rubbish. When your system is in both filmstrip and waveform mode, MSP has to do far less work when displaying the video frames than it has to do for the waveform.

For example, a single DV clip filling the screen width* will show 29 or 30 video frames - needing about 4MB of picture data in order to decode. It doesn't matter if that's at full zoom (individual frames) or "fit in window" zoom. It doesn't matter if it's a five second, 17MB AVI or a one hour, 13GB AVI. The volume of data read from the disc, and the CPU overhead in decompressing that data to picture information is the same.

Audio, on the other hand, must be read in full. So that 13GB file will be trawled for its 675MB of uncompressed audio data and each pixel width will represent approx 3secs of audio - or 288,000** samples - to find the peak amplitude to get the appropriate height for the waveform display.

Even at full zoom, where you're only displaying just over a second (188 KB) of data, each pixel represents 154 samples which must be "peaked" to yield one pixel width of the waveform. It's less work than the full DV tape example above, so it may even be quicker than the frame display, but it's the only zoom level that is.

* A docked timeline on a maximised MSP window on a 1280 pixel wide screen, with each frame 40x35 pixels.
** 16 bit stereo @ 48 KHz

Skedton · Post by **Skedton** » Mon Mar 31, 2008 2:42 am

Thanks, guys.

Does that mean in lay terms that it's normal for scrolling the timeline in waveform mode to take much longer time to process that in filename mode. How come it takes the P4 Duo core to take about the same time as a P4 to process the same clip.

Would inreasing the RAM to 4 Gb help?

Post by **Ron P.** » Mon Mar 31, 2008 5:27 am

Simply because MSP8 was out way before the P4 Duo Cores, so it is not written to utilize both cores efficiently..

Devil · Post by **Devil** » Mon Mar 31, 2008 7:46 am

I disagree partially. It uses dual-cores exactly like it used dual processors and HT, for which it was written. Where I agree is the word 'efficiently'! In fact, any of these technologies will decrease rendering times by only 5-15%. The problem which the OP mentions is a question of the GUI processor, not the CPU nor the RAM (at least normally). There is a slight proviso here: if the GUI is on the motherboard and not a separate card, then a small amount of CPU and RAM horsepower is stolen to drive it. IMO, 4Gb RAM is unnecessary and will not make any difference, If the OP read the PLEASE READ THIS BEFORE POSTING... thread and complied, we would know better what we are dealing with.

Gorf · Post by **Gorf** » Mon Mar 31, 2008 9:25 am

Skedton wrote:Does that mean in lay terms that it's normal for scrolling the timeline in waveform mode to take much longer time to process that in filename mode <snip> Would inreasing the RAM to 4 Gb help?

No, nor would getting a faster CPU, or moving from on-board to a dedicated, high speed GPU. It's all down to the way MSP was written. Improving your system will speed up MSP performance overall, but will not significantly improve the relative performance of waveform vs frame display.

<snipped bit already answered by vidoman>

troppo · Post by **troppo** » Mon Mar 31, 2008 10:50 am

The GUI processor is the CPU, not the GPU. Windows XP does not use the GPU to assist in the display of windowed programs.

Skedton · Post by **Skedton** » Mon Mar 31, 2008 11:41 am

Thanks again, Guys.

So the hardware is not the culprit. Is there any other video editors that does this differently and faster?

My system is as follows:
CPU - Intel E6400
MB - Foxconn 1965G7MA-8EkRSZH
2 x 1GB Kingston DDR2-667 RAM
Onboard video & audio
Windows XP

troppo · Post by **troppo** » Tue Apr 01, 2008 1:02 am

I'd say that most other editors do things differently..