Resolutions
Bit rate
单位 bit/s
- 比如比特率为2000，时长为120分钟的一部电影，大小约为 2000 * 120 * 60 / 8 / 1024 = 1757MB
- 360p视频Overall bit rate建议550左右，一分钟大概4MB
MPEG-4
MPEG-4 Part 2
H.264 Levels
| Level | Maximum decoding speed |
Maximum frame size |
Maximum video bit rate for video coding layer |
Examples for high resolution @ highest frame rate (maximum stored frames) |
|---|---|---|---|---|
| 1 | 1,485 | 99 | 64 | 176×144@15.0 (4) |
| 1b | 1,485 | 99 | 128 | 176×144@15.0 (4) |
| 1.1 | 3,000 | 396 | 192 | 352×288@7.5 (2) |
| 1.2 | 6,000 | 396 | 384 | 352×288@15.2 (6) |
| 1.3 | 11,880 | 396 | 768 | 352×288@30.0 (6) |
| 2 | 11,880 | 396 | 2,000 | 352×288@30.0 (6) |
| 2.1 | 19,800 | 792 | 4,000 | 352×576@25.0 (6) |
| 2.2 | 20,250 | 1,620 | 4,000 | 720×576@12.5 (5) |
| 3 | 40,500 | 1,620 | 10,000 | 720×576@25.0 (5) |
| 3.1 | 108,000 | 3,600 | 14,000 | 1,280×720@30.0 (5) |
| 3.2 | 216,000 | 5,120 | 20,000 | 1,280×1,024@42.2 (4) |
| 4 | 245,760 | 8,192 | 20,000 | 2,048×1,024@30.0 (4) |
| 4.1 | 245,760 | 8,192 | 50,000 | 2,048×1,024@30.0 (4) |
| 4.2 | 522,240 | 8,704 | 50,000 | 2,048×1,080@60.0 (4) |
| 5 | 589,824 | 22,080 | 135,000 | 3,672×1,536@26.7 (5) |
| 5.1 | 983,040 | 36,864 | 240,000 | 4,096×2,304@26.7 (5) |
| 5.2 | 2,073,600 | 36,864 | 240,000 | 4,096×2,304@56.3 (5) |
| 6 | 4,177,920 | 139,264 | 240,000 | 8,192×4,320@30.2 (5) |
| 6.1 | 8,355,840 | 139,264 | 480,000 | 8,192×4,320@60.4 (5) |
| 6.2 | 16,711,680 | 139,264 | 800,000 | 8,192×4,320@120.9 (5) |
SRT
- A numeric counter indicating the number or position of the subtitle.
- Start and end time of the subtitle separated by
–>characters. - Subtitle text in one or more lines.
- A blank line indicating the end of the subtitle.
Dynamic Adaptive Streaming over HTTP
iOS Camera Record Video Settings
iOS的文件选择控件有三个来源，相册、拍照录像、文件。
- 相册中选择的视频会自动压缩，照片可选压缩级别
- 拍照时照片不会压缩，视频录像时会高度压缩（360p）
- 选择文件上传几乎不会改变大小
视频文件损毁
火狐浏览器显示文件损坏
Windwos无预览
