Example h264encode with Timestamp

Steps to reproduce
```bash
$dist/bin/h264encode
```
It writes the file **test.264** .

```bash
$ffmpeg -framerate 24 -i /tmp/test.264 -c copy /tmp/test.mp4
```

It output the warning message
```
[mp4 @ 0x1c76500] Timestamps are unset in a packet for stream 0. This is deprecated and will stop working in the future. Fix your code to set the timestamps properly
```

Please have a look, thanks in advance !