Using Smart Render & Same as First Video Clip

[Phil]

I carried out a simple test today as I noticed some deterioration on like for like footage after rendering a clip recently (using VSP X9)

My 10 second 1080p AVCHD clip was inserted to timeline. My test was to create the exact same clip with the exact same dimensions with no enhancements.

I then proceeded to Share and Create Video "Same as first video clip" I did this twice - one sample with "Enable Smart Render" checked and the other sample with it unchecked.

After these 2 x renders, I compared them in HD (no smart proxy on) to the original clip and compared them to one particular frame. To my surprise, rendering as "Same as first video clip" without the Smart render checked will degrade your video, EVEN THOUGH you would presume a like for like quality output. Despite encoding with the same dimensions, there is clearly interference in the encoding process and a level of video noise will be added to your footage.

My conclusion is to always check the box "Enable Smart Render" to obtain like for like output. It's not just a time saving checkbox.

Phil

[aljimenez]

Thanks for sharing. I wonder if somehow the bitrate in your original clip could not me matched by the VS encoder.

[Phil]

I've brought the original and the 2 tests back to the timeline and checked their properties. All identical (Panasonic GH2 camera H.264 Video UFF, 1920x1080 max 21718kbps).

It's a concern that by making any type of video clip that's not Smart Rendered, even with the same dimensions, will degrade by process of the encoding mechanisms.

[aljimenez]

In your first post you say the video files were AVCHD, and I think the GH2 only does AVCHD 1080i and MJPEG. It is possible that the render is being converted to 1080p, or the interlaced source is not being handled correctly.

I am so happy those days of interlace video are pretty much gone now. I recall so many discussions of handling interlace video woes. BTW, I still have a GH2, and it is hacked with 2fps MJPEG for timelapse video. I also have one of the robust hacks that add quality to its 1080i capture. But I now use a GH4 for my videos which does not capture anything interlaced.

[Phil]

Sorry thats right, it is 1080i Upper Field First and as all clips were produced on the basis of "Same as first clip" then the tests clips were all produced the same.

If I were to mix 1080p clips from my other cameras, should I render the final version as a "1080p" video?

[aljimenez]

I recommend you in fact try out your original render with 1080p and see if VS handles the interlace conversion well. I have a feeling it may come out with better quality. I would read the old stuff on interlace video in other forums (much has been written that I have forgotten now). I would figure out the conversion from 1080i into 1080p and do that with all your video clips from the GH2 before beginning the edit process.

[Phil]

A quick test shows that converting 1080i from the GH2 in order to match my other 1080p cameras and our PAL standard (25fps), that there is a similar deterioration.

My GH2 can also shoot 24fps progressive. If I have GH2 clips at 1080/24p and make a final render to 25fps, does VSP make up the final frame per second?

[Ken Berry]

If I have GH2 clips at 1080/24p and make a final render to 25fps, does VSP make up the final frame per second?

Yes, it would simply repeat a frame. Depending on the action in the video, this might or might not be visible as a minor blip -- possibly less visible if the action is fast-moving...

[Phil]

I have made another disturbing discovery on this subject.

Today, I set up my GH2 (upper field first, 25fps) to record and compare the built-in colour/scene options (e.g. vibrant, nature, standard etc etc). The task being to view these clips of about 10sec each, label them with the appropriate description and make one continuous clip using the same video dimensions.

Unfortunately, the addition of titles in the title track cause Videostudio x9 to re-encode EVERYTHING despite selecting to render "Same as First Video Clip" and "Enable Smart Render". I noticed that pixels were "shifting" about in finer areas such as in grass. Not so in the original nor when rendered without titles. I tried a different approach by putting titles in the video overlay track. No improvements.

This seems to be an issue with interlace video.

What is the work around here?

[canuck]

Of course everything has to be rerendered since you are adding text to each clip. The text has to be "merged" with the video and that requires rerendereing

[Phil]

It's a disappointment that the original video gets ruined and can't be preserved

[canuck]

It's a disappointment that the original video gets ruined and can't be preserved

Where did you get the idea that the "original video gets ruined and can't be preserved"? When you render a video, a new video file is created and the original video file is not modified in any way. The only way that the original video is changed if you deliberately specify to overwrite the original by giving it the same name and folder.

If you are afraid that the original may get corrupted, you can always first make a copy and store it somewhere safe.

[Phil]

Sorry, it's the way I've typed it. The original video still remains of course.

What I mean is, it's a disappointment that by simply adding a title, the perfect video has to be re-rendered hence losing it originality

[aljimenez]

Instead of a Title, adding voice over may leave original video intact. Another idea is to add a panel before each video clip with the Title.

[canuck]

Sorry, it's the way I've typed it. The original video still remains of course.

What I mean is, it's a disappointment that by simply adding a title, the perfect video has to be re-rendered hence losing it originality

The video already lost its originality when you created the video from the initial raw video.
If you want the text not to be hardcoded into the video, you will have to create a subtitle file. VideoStudio contains a subtitle editor with which you can create the subtitle file. This is a text file which can also be edited with any text editor.
Of course you video player has to be able to "read" these subtitle files in order to display the text titles.