Faster render depends on how I trim (CPU load)

[laurentje]

I have a vey strange behaviour of VSx10 when rendering a serie of concatenated trimmed clips on the timeline. At te very beginning I had the impression that VSX10 was SLOW at rendering.

When in the Share-step, I start to render the video I saw sometimes that the CPU use was low (25%), sometimes high (above 90%) and keeping an eye on Task Manager (tab Performance) and an eye on the Preview during rendering and I saw also that it depends on the clip being rendered.
I apply no filters, nor transition effect, only trimmed clips on the timeline, no Smart Render. The clips come from my camcorder a Sony AX53 format m2ts 1920x1080i50. Output to the same format m2t 1920x1080i50, same attributes as my input clips.

After a couple of tests the conclusion was that the speed of render was largely based on how I trimmed the start and the end of each clip. If I round up to a multiple of 10 (frames) the whole project was rendered nearly 100% of each logical CPU-core and therefore perhaps 5-times faster.

Example. At the start of a clip I want to start at 1"13 ==> I round at 1"10; other possible values 00, 10 or 20 ==> so 1"00 or 1"10 or 1"20. I trim the end of each clip the same way. Working in such a way makes that all logical cores of the CPU works at 100%.

A bug perhaps related with this. Start selecting the last clip on the time-line, go back (Tab back) on the time line, normally the pointer in the preview window sits then above the last frame of the click. But sometimes the pointer is above the second last frame....This behavior is not consistent..

I consider this as a bug of VideoStudio: a CPU only loaded at 25% and there is no other bottleneck (SSD-drive, VS do not use of GPU,...) proves that the coding is not up to date with modern processors. I have not this problem with Handbrake, PowerDirector, Megui....

My question is now: what is the experience of others concerning CPU-load?

[lata]

I ran a few render tests the other day, comparing different output settings.

http://forum.corel.com/EN/viewtopic.php ... 31#p350080

But yes how we edit and the filters we apply will affect render times.

If there are a lot of changes, filters applied will increase the workload for the encoder / engine, but that may reduce the CPU load as the program is struggling to convert the project.

I do not have a graphics card but my cpu as you see from the tests is doing the job, as its up at 90% then VS is also performing in sending the data to the cpu.

Take care when testing render times as Smart Render will influence your results, especially for second renders.

[lata]

Using Smart Render
Just ran a quick test using MTS, 12 clips total length 4 minutes, each clip was trimmed at beginning and end.
Render took 1 min 22 sec. CPU load between 35% - 60%
Then I rendered the full project , no trims, 5 minutes 12 sec duration
Rendered in 1 min 5 sec, cpu load 35% - 60%

No Smart Render
Trimmed project duration 4 minutes
Video Studio CPU load 80% ish
Render time 5 min 40 sec.

Full project 5 minutes 12 sec, no cuts
Video Studio CPU load 75 - 80% ish
Rendered in 7 min 30 sec

Given that the last project was approx. 30% longer one would expect a longer render time.
Not sure what this means?

[laurentje]

Using Smart Render
Just ran a quick test using MTS, 12 clips total length 4 minutes, each clip was trimmed at beginning and end.
Render took 1 min 22 sec. CPU load between 35% - 60%
--

I cannot run Smart Render because of out of sync of the audio at the end (2"); thus only full render 13' total duration for 90 clips, render time: 21'. No filter, no transition effect, only a simple concatenation. Do you think this is normal?

[lata]

Hi

Out of sync audio after rendering does happen but usually it is the video format that is unusual,
Maybe video studio struggling to read the format, so many variations out there.

What are the properties of your video file?
Do your project properties match the video file? at least the frame rate.

Variable frame rates cause problems for video editors, usually from tablets, I phones etc.
Where did you get the video from?

Right click the video clip on the timeline and choose properties, what are they?
Create an image of that panel to attach to your post, saves on typing.

[laurentje]

...
Right click the video clip on the timeline and choose properties, what are they? ....

Properties:
file format: PAL HDMV
file size: 59 328 KB (57.9 MB)
Duration:29.640 seconds
Video
Video type: H.264 Video, Upper Field First
Total frames: 741 frame(s)
Attributes: 24 bits, 1920x1080,16:9
Data rate: Variable bit rate (Max 16000 kbps)
Audio
Audio type: Dolby Digital Audio
Total samples: 1 422 720 Samples
Attributes: 48000 Hz, 5.1 Channels
Layer: None
Bit rate: 448 kbps


Properties output file:
MPEG Transport-Stream Files
24 bits, 1920 x 1080, 25 fps
Upper Field First
(HDMV-PAL), 16:9
H.264 Video
Video data rate: Variable (Max. 16000 kbps)
Audio data rate: 448 kbps
Dolby Digital Audio, 48 KHz, 3/2(L,C,R,SL,SR)

So it is the same for me and nothing special these days.
Clips are coming from my camcorder Sony AX-53.

[lata]

The video files I used for my tests were MTS and same as your properties other than the data rate being 16800kbps.
With no smart render I am quite happy with the times at just over real time.
Smart Render improves times.
The CPU % was Video Studios usage, so where I said 80% the total CPU usage was 95+
Video Studio is throwing the data at the CPU which is fully loaded so doing its job.
The only way to improve that is to have more cores.

CPU tends to be low when first starting to render and ramps up, when the timeline contains edits then the CPU will fall and rise as the encoder finds it harder to render.
I do not normally view my CPU usage, I just let it get on with it.

My first pc took 8 times, a 40 minute project taking 320 minutes , yep that's long. (project containing standard edits)
My last pc took approx. 2.25 times
Now my pc does it in real time, that is using Smart Render

How long does it take you to render 10 clips approx. 5 minutes duration

Out of Sync audio
I would not have thought there was a problem with MTS, I have to say the my sound is usually background sound and not lip sync, so I would not notice sync issues.