Difference between revisions of "Video-Editing-using-Blender/C2/Build-Proxy-for-Video-Editing/English"

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|  | Cursor on '''Preview''' panel.
 
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|  | We can also move the Playhead over the region to see the lag in preview.
 
|  | We can also move the Playhead over the region to see the lag in preview.
  

Revision as of 13:50, 11 February 2021

Visual Cue Narration
Slide Number 1

Title Slide

Welcome to the tutorial on Build Proxy for Video Editing.
Slide Number 2

Learning Objectives

In this tutorial, we will learn about,
  • High definition video
  • About time lag in playing the video
  • Why a proxy is needed
  • Building a Proxy and settings and
  • Changing memory cache size
Slide Number 3

System and Software Requirement

To record this tutorial, I am using
  • Ubuntu Linux v18.04 OS and
  • Blender 2.90.1
Slide Number 4

Pre-requisites

https://www.spoken-tutorial.org

To follow this tutorial,
  • Learner must be familiar with the Blender interface.
  • For pre-requisite tutorials, please visit this site.
Slide Number 5

Code Files

  • Files used in this tutorial are provided in the Code files link.
  • Please download and extract the files.
  • Make a copy and then use them while practising.
Show opened blender interface. I have already opened the blender interface in Video editing mode.
Go to the Videos folder in the File browser. Go to the Videos folder in the File browser.
Add proxy.webm in the Sequencer panel. I have saved the input file, proxy.webm in the Videos folder.

Let’s add it to the Sequencer panel.

Slide Number 6

Download Link

https://commons.wikimedia.org/wiki/File:Birds_in_the_backyard_58.webm

* The input file was downloaded from the wikimedia website as shown here.
Zoom out in the Sequencer panel. Let’s zoom out the video in the Sequencer panel.
Point to the lighter shaded region in the Sequencer panel. Notice the playback range is seen in a lighter shade.


It is from 1 to 250 frames only.

Highlight the frame numbers in the Timeline editor header. They are displayed in the Timeline editor header.

The video is much longer.

Cursor on the Sequencer panel. Let’s change the playback range to play all the frames in the video.
Adjust the zoom and scroll the field of view. Adjust the zoom and scroll the field of view to your convenience.
Adjust the zoom and scroll the field of view. Move the playhead to the end of the video to check the frame number.
Cursor at the current frame number. Frame number at the playhead is also displayed in the Timeline editor header.

Note this number as seen here.

Change end of playback to 2700. Double click on the right most form in the header, which reads 250.

I will change it to 2700, to include the full video for playback.

Scroll from 2700 to 0 frames to show change in playback region. The lightly shaded region, which indicates the playback range moves to 2700.

Now the whole video will get played.

Cursor on the Source resolution in Strip tab. Notice the high resolution of the input video.


Select the audio clip and uncheck the box against the file name. Select the audio clip.

For clarity in narration, I will mute the audio now, as seen here.

Pause this video and play the input file which is in high definition.

Zoom out the video in the Preview panel. Let’s zoom out the video in the Preview panel.
Play the video for few seconds. Play the video around the one minute region.

Notice that, the displayed fps varies as the video is played.

Cursor on Preview panel. The video lags and is not smoothly played.
Stop playing the video. Let’s stop playing the video.
Move Playhead to show lag. We can also move the Playhead over the region to see the lag in preview.

The computer could be slow or the video is of a larger size.

Slide Number 7

Building a Proxy

When working with HD videos,
  • Creating a proxy setting is very important in video editing.
  • It is to be done before starting to edit the videos.
Select the video strip.

In the Preview panel, click on View, Proxy, Setup.

Select the video strip.

In the Preview panel, click on View, Proxy, and then Setup.

A small window opens.

Check the box for 25% and click on Ok. Notice that, proxy is not set up currently.

I will check the box for 25% and click on Ok.

Cursor in Preview panel. This means that, the resolution of the output will be less and hence grainy.

Finer details in the video may not be discernible in the proxy.

Click on Sidebar, Proxy & cache tab and scroll down. Go to the Sidebar in the Sequencer panel.


Proxy setting can be accessed through the Proxy & cache tab in the Sidebar.

Click, hold and drag on the left edge of Sidebar to resize. I will make the panel a bit larger for clarity, as seen here.
Scroll down to Proxy Settings section.

Click twice on the arrow on the left.

Scroll down to the Proxy Settings section.

If you do not see the options, click on the arrow to the left to show them.

Click on the Storage option. Click on the Storage option.

Proxy can be set for a single strip or for the project.

Cursor next to Strip proxy and timecode. Scroll down and notice the options under Strip proxy and timecode.
Check the box to define Directory for Custom proxy. Let’s check the box to define Directory for saving the Custom proxy files.
Click on the folder icon on the right of the form. A new form with directory name appears.

Click on the folder icon on the right of the form to open a dialogue box.

Cursor on the dialogue box and the folder + icon on the top. Select a folder of your choice or create a new one.

Use the folder plus icon to create a new directory.

Blender will save the proxy files in this folder.

Click on Cancel. Now I will not change it.
Type Proxy for the new file name. If we don’t create a separate folder, Blender will create one.

A BL_proxy folder is created by Blender, in the same folder as the video file.


Uncheck the box for Directory selection. Some users may have a bug in creating a new folder.

For now, I will uncheck the box for Directory selection.

Click the check box for File twice. The File option allows you to read in existing proxy file settings.

Now I will not change it.

For Resolution, click on 25%. For Resolution, click on 25% to choose it.
Check the box for Overwrite. I will also check the box for Overwrite.
Change value for Build JPEG quality to 30. I will change the value for Build Jpeg quality, to 30.

Enter the value in the form or click hold and move the mouse on the form.

Scroll up in the tab. Let’s scroll up in the tab.
Click on Rebuild Proxy and Timecode indices. Click on Rebuild Proxy and Timecode indices.
Cursor on the progress bar in the right corner on building proxies. A progress bar is seen in the right corner, on Building proxies.

Allow the process to be completed.

Slide Number 8

Matched Settings

Proxies with matching resolution must be set in
  • Proxy setting in the Proxy and Cache panel and
  • In the Preview panel
Click on View, Proxy and choose Set window size. Click on View, Proxy and choose Scene render size.
From the submenu, choose Proxy size 25%. From the submenu, I will choose Proxy size as 25%.
Play the video for few seconds. Now let's play the video.

Notice the fps shows as 25 and the video plays smoothly without lag.

If the proxy is not set in the preview panel, the proxy files which were created will not be utilized.

The video is now more pixelated and finer details are missing at 25% resolution.

Stop playing the video. Let’s stop playing the video.
Cursor on Blender window. You may be able to increase the size of cache memory which Blender can use.

This process also decreases the lag.

Click on Edit, Preferences. Click on Edit, Preferences to open the Blender Preferences window.
Click on the System tab. Click on the System tab on the left.
Cursor on the Memory Cache Limit. Notice that, my Memory Cache Limit is already at 4MB.

It could be different for you.

Close the Blender Preferences. If your hardware permits, you may increase this with caution.

Mine is at it’s limit and I will not change it.

Close the Blender Preferences Window.

Pause the video, explore more options and familiarize with proxy setting.
Show screenshot of the files in proxy directory. You may explore the low resolution video files Blender has created.

We had created a proxy folder for the files to be saved.

Cursor on the Blender interface. Make the desired edits, after setting the proxy.

When final rendering is done, the proxy will not be used.

Show File, Save and File, Quit. You may, save the project and quit Blender.
Slide Number 9

Summary

Now let's summarize. In this tutorial, we learned about,
  • High definition video
  • Time lag in playing the video
  • Parameters for proxy settings
  • Created low resolution videos of the starting video
  • Learned about memory cache size
Slide Number 10

Assignment

For assignment activity, please do the following.
  • Practice to build proxies with different resolution.
  • Explore the lower resolution output video which was created.
Slide Number 11

Assignment

* You may also use a video of your choice to create proxy.
Slide Number 12

Spoken Tutorial Project

This video summarises the Spoken Tutorial Project.

Please download and watch it.

Slide Number 13

Spoken Tutorial workshops

The Spoken Tutorial Project team:
  • Conducts workshops and
  • Gives certificates.

Please write to us.

Slide Number 14

Forum for specific questions:

Please post your timed queries in this forum.
Slide Number 15

Acknowledgment

Spoken Tutorial Project is funded by MHRD, Government of India.
This is Rani from IIT Bombay. Thank you for joining.

Contributors and Content Editors

Ranipv076, Snehalathak

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