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| Unofficial VirtualDub Support Forums > Newbie Questions > A Question On Speeding Up Videos |
| Posted by: BelGarion Apr 23 2012, 02:25 PM |
| Now I know you can change the FPS to bump up your video speed, so 30fps to 300fps would be a 10x increase. But can you do this for a segment of a video? Like mark a start point, an end point, and some how tell it just for the selection, bump the FPS up 10x and *maybe* also remove the audio portion and/or substitute it for normal speed audio that fits into the new slot (so a 3 min segment going 10x faster would now be ... Guessing here... 3 min is 180 sec, so ... 18 seconds? ) ? Like you see on YouTube where someone is building something in, oh, Minecraft, and they fast forward the boring bits and you hear GNU Free music playing as they speed though the task at 10x. I could probably do it in some really expensive professional program but wanted to do it in VirtualDub if it's possible. |
| Posted by: malky Apr 23 2012, 09:16 PM |
| What's the source frame rate? I found that I had to use two different methods for 25 and 29.97 else you get error messages when trying to append the segments back together. |
| Posted by: BelGarion Apr 24 2012, 07:10 AM | ||
29.97 or 30 FPS. |
| Posted by: malky Apr 24 2012, 10:07 AM |
| I'll just post the notes I made when doing it. Pick out the bits that are relevant to you. Note that the I used 30000/1001 instead of 29.97 - you don't have to use that ratio when it comes to 25 or 30. ============================================================== 29.97 fps has problems when appending in VirtualDub, so settings differ from 25 or 30fps. Lame mp3 codec and XviD are assumed.‘Audio is assumed to be 48k, 128, cbr. ‘Audio from other file ..’ if used is assumed to be 48k, 128, cbr. All parts will be saved using Video > Smart Rendering and the video compressed using XviD codec. Use the Delete key to clear selections before making new selections. Assuming that you have a file and you want part of it (the middle) speeded up, you can do it this way: Load the file, and click 'File' => 'File information’, note the video FPS and audio sample rate. Assume 29.97fps and 48000, 128 CBR stereo. Select the first segment start/finish using the slider control and the little 'flag' thingies. Click Video > Full processing > Smart Rendering > Compression, select XviD codec: Click 'Video' > 'Frame rate' > 'Video Frame Rate Control', 'Source Rate Adjustment'> 'Change Frame Rate to FPS' enter 30000/1001 Beneath that in the next section, 'Frame rate conversion' > ‘Convert to fps:’ set it at 29.97fps. Click Audio > Full processing > Compression> Lame MP3 48000, 128, CBR. Click ‘File’ and save the first segment p1.avi Clear the selection with the Del key. =================================================== Move the slider to the end point for the second (fast) segment. Click 'Video' > 'Frame rate' > 'Video Frame Rate Control'> 'Source Rate Adjustment'> 'Change Frame rate to FPS' enter 2000 (A 40 minute segment will now run ~ 30 seconds) Beneath that in the next section, 'Frame rate conversion'>‘Convert to fps:’ leave at 29.97fps. Assuming a new audio is to be attached to the speeded up segment : Click 'Audio' > 'Audio from other file' - this file should be at least the same length as the speeded up segment. (If the length of the selected segment is now 40 seconds, so should the ‘Other file’ audio). Save second part (P2). Clear the selection with the Del key. =================================================== Select the third part. Set the audio and video back to the original settings: Audio > ‘Source audio’ instead of ‘Other file’ audio. 'Video' > 'Frame rate' > 'Video Frame Rate Control'> 'Source Rate Adjustment'> 'Change Frame Rate to FPS' and enter 30000/1001 Beneath that in the next section, 'Frame rate conversion' > ‘Convert to fps:’ leave at 29.97fps. Save the third part (P3). Close. Restart VirtualDub load P1 and append P2 (P3 should load automatically); Set Video > Direct stream copy and save. |