For last few days I spent many hours to learn about video editing in GNU/Linux.
GoPro HD Hero2 camera produces big MP4 files. For example 25 minutes of video file is around 2.3 GB at 1280×960 (default) resolution. I was surprised at seeing this huge size.
The minimum resolution I can get is 1280×720 with 30 fps. It reduces video file size ten to fifteen percent. Below is the sample files I made. All of them have twenty three to twenty five minutes of length.
2.3G Aug 5 14:15 GOPR0008.MP4
2.2G Aug 5 14:22 GOPR0009.MP4
1.9G Aug 7 14:26 GOPR0014.MP4
vlc plays big files flawlessly. But fun thing starts in video editing. Whatever jobs I did from cutting, converting to other format, video editing, I had to twenty to forty minutes till the job finished.
Big file demands more time and resources than small file. I doubt Youtube wouldn’t take over 700B size of short video. Uploading few hundred mega bytes takes long especially to foreign website.
To shorten the video editing process I made a ten minutes length of MP4 file and created different resolutions to get small and good quality video files. Three element affects video file size: resolution, video bitrate, and frame rate.
The raw mp4 file has 1280×720 at 30 fps. Width is 1280 pixels, height is 720 pixels, 30 frames per second. Its video bitrate is 9894 kb/s (close to 1000k kb/s)
805ride-480×360-tiny.mp4 has 480×360 resolution, video bitrate is 1454 kb/s. Small resolution decreases the file size about seven times.
805ride-480×360-200k.mp4 has the lowest video bitrate, which is 200k kb/s. The quality degradation is outstanding.
718M Aug 8 15:43 805ride-10min.mp4
41M Aug 8 19:32 805ride-320x240-500k.mp4
34M Aug 8 21:00 805ride-480x270-400k.mp4
20M Aug 8 18:22 805ride-480x360-200k.mp4
33M Aug 8 18:45 805ride-480x360-384k.mp4
122M Aug 8 17:36 805ride-480x360.mp4
114M Aug 8 17:56 805ride-480x360-tiny.mp4
I put music on 805ride-480×270-400k.mp4 and trimmed it to upload on Youtube.
The finished video file has 20M size with avi format. Overall size reduction is pretty good though.
It’s hard to imagine how many hours I’ll waste while video editing on my aging desktop. Anyway, I’ll post encoding options I used on ffmpeg later on.