Answers.Body: <p>I fulfilled my requirement in Adobe Premiere Pro by following the below procedure:</p>
  
  <ol>
  <li><p>Load the complete video in Timeline panel.</p></li>
  <li><p>Using 'Razor' tool cut the section which I need to blur. When we cut using 'Razor' tool, Adobe Premiere Pro marks it as a logical separate clip.</p></li>
  <li><p>Drag the <em>Video → Blur</em> effect on the desired clip and set the Gaussian blur settings.</p></li>
  <li><p>Repeat the above steps for all other sections of the original video which I need to blur.</p></li>
  <li><p>In the end, Export the complete sequence.</p></li>
  </ol>
  
Answers.ContentLicense: CC BY-SA 3.0
Answers.CreationDate: 2013-07-04T08:35:34.033Z
Answers.LastActivityDate: 2015-03-29T17:07:06.507Z
Answers.LastEditDate: 2015-03-29T17:07:06.507Z
Answers.UserDisplayName: user1451111
Answers.Body: <p>You can use ffmpeg, and you currently have a choice of four video filters that can blur: <a href="http://ffmpeg.org/ffmpeg-filters.html#boxblur" rel="noreferrer"><code>boxblur</code></a>, <a href="http://ffmpeg.org/ffmpeg-filters.html#sab" rel="noreferrer"><code>sab</code></a>, <a href="http://ffmpeg.org/ffmpeg-filters.html#smartblur-1" rel="noreferrer"><code>smartblur</code></a> and <a href="http://ffmpeg.org/ffmpeg-filters.html#unsharp" rel="noreferrer"><code>unsharp</code></a>. These filters can use the <code>enable</code> option for <a href="http://ffmpeg.org/ffmpeg-filters.html#Timeline-editing" rel="noreferrer">timeline</a> support, so you can apply the blurring effect to a certain duration if desired. You can view what filters have timeline support with <code>ffmpeg -filters</code>.</p>
  
  <h3>Example</h3>
  
  <p><img src="https://i.sstatic.net/iwCqE.png" alt="original image">
  <img src="https://i.sstatic.net/ON6Hz.jpg" alt="boxblur"></p>
  
  <p>This example will apply the blur from 22-113 seconds, then again from 275-286 seconds:</p>
  
  <pre><code>ffmpeg -i input.avi -vf "boxblur=enable='between(t,22,113)',boxblur=enable='between(t,(60*4)+35,286)" -codec:a copy output.avi
  </code></pre>
  
  <ul>
  <li><p>You can enter seconds or have it calculate seconds for you as shown in the example.</p></li>
  <li><p><a href="http://ffmpeg.org/ffmpeg-utils.html#Expression-Evaluation" rel="noreferrer">Expression evaluation</a> is not my best area. You may find a method to declare the filter just once.</p></li>
  <li><p>Note that, since you only want to modify the video, the audio can be <a href="https://ffmpeg.org/ffmpeg.html#Stream-copy" rel="noreferrer">stream copied</a> from the input to the output without re-encoding. This is faster than re-encoding and will preserve the quality. This is something most editors, such as Premiere, do not support without additional shenanigans.</p></li>
  </ul>
  
  <h3>Preview</h3>
  
  <p>If you have <code>ffplay</code> you can get a preview instead of encoding, watching, re-encoding...</p>
  
  <pre><code>ffplay -i input -vf smartblur
  </code></pre>
  
  <h3>Getting <code>ffmpeg</code></h3>
  
  <p>Builds are available for Windows, Linux, and OS X users. See the <a href="https://ffmpeg.org/download.html" rel="noreferrer">FFmpeg Download</a> page, but of course you can always <a href="https://trac.ffmpeg.org/wiki/CompilationGuide" rel="noreferrer">compile <code>ffmpeg</code></a> too.</p>
  
Answers.ContentLicense: CC BY-SA 3.0
Answers.CreationDate: 2015-03-29T08:29:45.787Z
Answers.Text: For which filters is timeline supported? I would like to use "setpts" and "atempo" (to speed up certaing fragments in a video), but it doesn't work for me (@No option name near '2'@). Do I have an old version, am not passing the parameters correctly or the timeline is not supported?
Answers.UserDisplayName: Jānis Elmeris
Answers.ContentLicense: CC BY-SA 3.0
Answers.CreationDate: 2015-03-29T17:04:40.007Z
Answers.Text: @Janis Neither of those filters have timeline support. See `ffmpeg -filters`.
Answers.UserDisplayName: llogan
Answers.ContentLicense: CC BY-SA 4.0
Answers.CreationDate: 2021-03-06T19:55:35.100Z
Answers.Text: `audio can be stream copied`, so video can't be stream copied? Even though we only want to modify a tiny fraction of the video? Guess I'll better cut it out, blur, then join back.
Answers.UserDisplayName: Klesun
Answers.ContentLicense: CC BY-SA 4.0
Answers.CreationDate: 2021-03-07T18:43:09.367Z
Answers.Text: @Klesun You can't filter and stream copy the same stream, but what you can do is cut out a section exactly on key frames, filter that section, and concatenate with the concat demuxer. See [Cut a video in between key frames without re-encoding the full video using ffpmeg?](https://stackoverflow.com/a/63604858/) for an example.
Answers.UserDisplayName: llogan
Answers.ContentLicense: CC BY-SA 4.0
Answers.CreationDate: 2021-06-17T15:35:04.037Z
Answers.Text: Important missing part: to change the blur level, you have to replace `boxblur=` with for example `boxblur=10:` (found in this answer: https://superuser.com/questions/1088062/how-to-conditionally-blur-video-using-ffmpg/1088096#1088096)
Answers.UserDisplayName: baptx
Answers.ContentLicense: CC BY-SA 3.0
Answers.CreationDate: 2013-07-02T23:22:12.087Z
Answers.LastActivityDate: 2015-03-29T17:03:57.213Z
Answers.LastEditDate: 2015-03-29T17:03:57.213Z
Answers.UserDisplayName: llogan
Answers.Body: <p>Premiere can certainly do what you need.  You could either cut the clip into sub-clips and apply a blur filter or you could apply a filter and keyframe the level of blur.  Note that this would be if you are trying to blur the entire frame.  If you want to blur only a portion of the frame, you would probably want something like motion tracking in After Effects that could follow the thing you want to blur and limit the blur to only the area impacted by a mask that follows the motion.</p>
  
Answers.ContentLicense: CC BY-SA 3.0
Answers.CreationDate: 2013-07-01T08:29:31.003Z
Answers.Text: I want to blur the entire screen, not just a single object. Is it possible
Answers.UserDisplayName: user1451111
Answers.ContentLicense: CC BY-SA 3.0
Answers.CreationDate: 2013-07-01T13:25:25.763Z
Answers.Text: @user1451111 - yes, then just use the filter in Premiere like I suggested.  I was just mentioning that if you wanted to be more targeted than the whole frame, it would need more advanced software.  Blurring the whole frame is trivial.
Answers.UserDisplayName: AJ Henderson
Answers.ContentLicense: CC BY-SA 3.0
Answers.CreationDate: 2013-07-02T08:42:27.657Z
Answers.Text: Let's say I have a 5 minute video and I want to blur the following two segments within it.
  00:00:22 - 00:01:53 and 
  00:04:35 - 00:04:46
  How to proceed?
Answers.UserDisplayName: user1451111
Answers.ContentLicense: CC BY-SA 3.0
Answers.CreationDate: 2013-07-02T13:34:27.783Z
Answers.Text: You can either break them in to two subclips using the razor tool (looks like a little razor blade) and apply filters to each of the subclips you want to blur or you can apply blur to the whole thing and then use keyframes on the parameters of the effect to adjust the amount of blur to be 0 during the time you don't want blur.
Answers.UserDisplayName: AJ Henderson
Answers.ContentLicense: CC BY-SA 3.0
Answers.CreationDate: 2013-07-01T04:41:27.977Z
Answers.LastActivityDate: 2013-07-01T04:41:27.977Z
Answers.UserDisplayName: AJ Henderson
Body: <p>I need a software which can blur a scene from a video file. I have thought about VirtualDub and Adobe Premiere but I am not sure if they provide the desired functionality.</p>
  
  <p>My requirement is to blur a some-seconds scene for example blur the scene from 10:12 to 10:45 in a video file.</p>
  
Tags: <video>
Title: how to blur a short scene in a video
UserDisplayName: user1451111
ThreadText: # how to blur a short scene in a video
  
  (Asked by: username_0 on 2013-06-30)
  
  I need a software which can blur a scene from a video file. I have thought about VirtualDub and Adobe Premiere but I am not sure if they provide the desired functionality.
  
  My requirement is to blur a some-seconds scene for example blur the scene from 10:12 to 10:45 in a video file.
  
  **Tags:** video
  
  
  ---
  
  ## 3 answers
  
  ### Answer by username_0 on 2013-07-04. Score: 2 | Accepted answer
  
  I fulfilled my requirement in Adobe Premiere Pro by following the below procedure:
  
  1. Load the complete video in Timeline panel.
  2. Using 'Razor' tool cut the section which I need to blur. When we cut using 'Razor' tool, Adobe Premiere Pro marks it as a logical separate clip.
  3. Drag the *Video → Blur* effect on the desired clip and set the Gaussian blur settings.
  4. Repeat the above steps for all other sections of the original video which I need to blur.
  5. In the end, Export the complete sequence.
  
  
  ---
  
  ### Answer by username_1 on 2013-07-02. Score: 16
  
  You can use ffmpeg, and you currently have a choice of four video filters that can blur: [`boxblur`](http://ffmpeg.org/ffmpeg-filters.html#boxblur), [`sab`](http://ffmpeg.org/ffmpeg-filters.html#sab), [`smartblur`](http://ffmpeg.org/ffmpeg-filters.html#smartblur-1) and [`unsharp`](http://ffmpeg.org/ffmpeg-filters.html#unsharp). These filters can use the `enable` option for [timeline](http://ffmpeg.org/ffmpeg-filters.html#Timeline-editing) support, so you can apply the blurring effect to a certain duration if desired. You can view what filters have timeline support with `ffmpeg -filters`.
  
  ### Example
  
  ![original image](https://i.sstatic.net/iwCqE.png)
  ![boxblur](https://i.sstatic.net/ON6Hz.jpg)
  
  This example will apply the blur from 22-113 seconds, then again from 275-286 seconds:
  
  ```
  ffmpeg -i input.avi -vf "boxblur=enable='between(t,22,113)',boxblur=enable='between(t,(60*4)+35,286)" -codec:a copy output.avi
  
  ```
  
  * You can enter seconds or have it calculate seconds for you as shown in the example.
  * [Expression evaluation](http://ffmpeg.org/ffmpeg-utils.html#Expression-Evaluation) is not my best area. You may find a method to declare the filter just once.
  * Note that, since you only want to modify the video, the audio can be [stream copied](https://ffmpeg.org/ffmpeg.html#Stream-copy) from the input to the output without re-encoding. This is faster than re-encoding and will preserve the quality. This is something most editors, such as Premiere, do not support without additional shenanigans.
  
  ### Preview
  
  If you have `ffplay` you can get a preview instead of encoding, watching, re-encoding...
  
  ```
  ffplay -i input -vf smartblur
  
  ```
  
  ### Getting `ffmpeg`
  
  Builds are available for Windows, Linux, and OS X users. See the [FFmpeg Download](https://ffmpeg.org/download.html) page, but of course you can always [compile `ffmpeg`](https://trac.ffmpeg.org/wiki/CompilationGuide) too.
  
  > **Comments:**
  > **username_2**: For which filters is timeline supported? I would like to use "setpts" and "atempo" (to speed up certaing fragments in a video), but it doesn't work for me (@No option name near '2'@). Do I have an old version, am not passing the parameters correctly or the timeline is not supported?  
  > **username_1**: @Janis Neither of those filters have timeline support. See `ffmpeg -filters`.  
  > **username_3**: `audio can be stream copied`, so video can't be stream copied? Even though we only want to modify a tiny fraction of the video? Guess I'll better cut it out, blur, then join back.  
  > **username_1**: @username_3 You can't filter and stream copy the same stream, but what you can do is cut out a section exactly on key frames, filter that section, and concatenate with the concat demuxer. See [Cut a video in between key frames without re-encoding the full video using ffpmeg?](https://stackoverflow.com/a/63604858/) for an example.  
  > **username_4**: Important missing part: to change the blur level, you have to replace `boxblur=` with for example `boxblur=10:` (found in this answer: https://superuser.com/questions/1088062/how-to-conditionally-blur-video-using-ffmpg/1088096#1088096)  
  
  ---
  
  ### Answer by username_5 on 2013-07-01. Score: 2
  
  Premiere can certainly do what you need. You could either cut the clip into sub-clips and apply a blur filter or you could apply a filter and keyframe the level of blur. Note that this would be if you are trying to blur the entire frame. If you want to blur only a portion of the frame, you would probably want something like motion tracking in After Effects that could follow the thing you want to blur and limit the blur to only the area impacted by a mask that follows the motion.
  
  > **Comments:**
  > **username_0**: I want to blur the entire screen, not just a single object. Is it possible  
  > **username_5**: @username_0 - yes, then just use the filter in Premiere like I suggested.  I was just mentioning that if you wanted to be more targeted than the whole frame, it would need more advanced software.  Blurring the whole frame is trivial.  
  > **username_0**: Let's say I have a 5 minute video and I want to blur the following two segments within it. 00:00:22 - 00:01:53 and  00:04:35 - 00:04:46 How to proceed?  
  > **username_5**: You can either break them in to two subclips using the razor tool (looks like a little razor blade) and apply filters to each of the subclips you want to blur or you can apply blur to the whole thing and then use keyframes on the parameters of the effect to adjust the amount of blur to be 0 during the time you don't want blur.  
  
  ---
  
  