Answers.Body: <p>Every time I concat, I quickly run it thru this awesome little freeware from Mean beforehand, <a href="http://avidemux.sourceforge.net/" rel="nofollow noreferrer">avidemux</a>, (MP4 Muxer-&gt;Move index to the beginning of the file-&gt;Save) and it fixes the <em>majority</em> of any concat issues I've run into. Not sure if it will fix <em>your</em> issue, but it can't hurt and somewhere down the line avidemux <em>will</em> come in handy and fix a concat issue if you're having one. Shoutout to Mean for such a helpful piece of freeware!</p>
  
Answers.ContentLicense: CC BY-SA 4.0
Answers.CreationDate: 2021-02-06T04:34:41.570Z
Answers.Text: wonder if this is the same in ffmpeg: ffmpeg -i input.mp4 -codec copy -movflags +faststart output.mp4 (stackoverflow.com/questions/7614635/…) I tried this in ffmpeg and no difference in results. I'll try avidemux and see if its any different.
Answers.UserDisplayName: Sun
Answers.ContentLicense: CC BY-SA 4.0
Answers.CreationDate: 2021-02-04T12:20:53.527Z
Answers.LastActivityDate: 2021-02-04T12:20:53.527Z
Answers.UserDisplayName: John Alderson
Body: <p>I have a Zoom video that I &quot;cut&quot; into two videos:</p>
  <pre><code>ffmpeg -i 0131.mp4 -ss 55 -t 38:52 -codec copy 0131-1.mp4
  ffmpeg -i 0131.mp4 -ss 40:00 -t 1:52 -codec copy 0131-2.mp4
  </code></pre>
  <p>I then merged into one using [concat demuxer][1] in ffmpeg.</p>
  <p>The merged video plays, but the first 15 seconds of the merged video is blank (audio plays okay). What do I need to do so that first 15 seconds of the merged video also displays? Is this due to a &quot;keyframe&quot; not appearing for 15 seconds after my cut point?</p>
  <blockquote>
  <pre><code>Stream #0:0(und): Audio: aac (LC) (mp4a / 0x6134706D), 32000 Hz, mono, fltp, 126 kb/s (default)
  Metadata:
    creation_time   : 2021-01-31T21:53:20.000000Z
    handler_name    : AAC audio
  Stream #0:1(und): Video: h264 (High) (avc1 / 0x31637661), yuv420p, 1280x720, 741 kb/s, 25 fps, 25 tbr, 30k tbn, 60k tbc (default)
  Metadata:
    creation_time   : 2021-01-31T21:53:20.000000Z
    handler_name    : H.264/AVC video
    encoder         : AVC Coding
  Stream #0:2(und): Data: bin_data (text / 0x74786574), 0 kb/s
  Metadata:
    creation_time   : 2021-01-31T21:53:20.000000Z
    handler_name    : Text
  </code></pre>
  </blockquote>
  
Tags: <ffmpeg><editing>
Title: How do I make a trimmed video show the missing frames from a Zoom recording using ffmpeg?
UserDisplayName: Sun
ThreadText: # How do I make a trimmed video show the missing frames from a Zoom recording using ffmpeg?
  
  (Asked by: username_0 on 2021-02-01)
  
  I have a Zoom video that I "cut" into two videos:
  
  ```
  ffmpeg -i 0131.mp4 -ss 55 -t 38:52 -codec copy 0131-1.mp4
  ffmpeg -i 0131.mp4 -ss 40:00 -t 1:52 -codec copy 0131-2.mp4
  
  ```
  
  I then merged into one using [concat demuxer][1] in ffmpeg.
  
  The merged video plays, but the first 15 seconds of the merged video is blank (audio plays okay). What do I need to do so that first 15 seconds of the merged video also displays? Is this due to a "keyframe" not appearing for 15 seconds after my cut point?
  
  > ```
  > Stream #0:0(und): Audio: aac (LC) (mp4a / 0x6134706D), 32000 Hz, mono, fltp, 126 kb/s (default)
  > Metadata:
  >   creation_time   : 2021-01-31T21:53:20.000000Z
  >   handler_name    : AAC audio
  > Stream #0:1(und): Video: h264 (High) (avc1 / 0x31637661), yuv420p, 1280x720, 741 kb/s, 25 fps, 25 tbr, 30k tbn, 60k tbc (default)
  > Metadata:
  >   creation_time   : 2021-01-31T21:53:20.000000Z
  >   handler_name    : H.264/AVC video
  >   encoder         : AVC Coding
  > Stream #0:2(und): Data: bin_data (text / 0x74786574), 0 kb/s
  > Metadata:
  >   creation_time   : 2021-01-31T21:53:20.000000Z
  >   handler_name    : Text
  >
  > ```
  
  **Tags:** ffmpeg, editing
  
  
  ---
  
  ## 1 answers
  
  ### Answer by username_1 on 2021-02-04. Score: 0
  
  Every time I concat, I quickly run it thru this awesome little freeware from Mean beforehand, [avidemux](http://avidemux.sourceforge.net/), (MP4 Muxer->Move index to the beginning of the file->Save) and it fixes the *majority* of any concat issues I've run into. Not sure if it will fix *your* issue, but it can't hurt and somewhere down the line avidemux *will* come in handy and fix a concat issue if you're having one. Shoutout to Mean for such a helpful piece of freeware!
  
  > **Comments:**
  > **username_0**: wonder if this is the same in ffmpeg: ffmpeg -i input.mp4 -codec copy -movflags +faststart output.mp4 (stackoverflow.com/questions/7614635/…) I tried this in ffmpeg and no difference in results. I'll try avidemux and see if its any different.  
  
  ---
  
  