...
When first HLS subscribes connects to a stream on WCS server, especilally to CDN stream, it may take a time to split a stream to HLS segmets and to form a playlist. As a result, Safari browser on iOS devices may not be able to play HLS stream on the first attempt. To successfully play HLS stream in this case, the HLS preloader was added since build 5.2.371. The default preloader looks like this:
Since build 5.2.408 preloaders are divided by stream aspect ratio: 16:9, 4:3, 2:1
Default preloader segments are placed to /usr/local/FlashphonerWebCallserver/hls/.preloader folder when server is started
| Code Block | ||
|---|---|---|
| ||
lstree /usr/local/FlashphonerWebCallserverFlashphonerWebCallServer/hls/.preloader /usr/local/FlashphonerWebCallServer/hls/.preloader -rw-r--r-- 1 root root 51888 Oct 13 04:47 ├── 16x9 │ ├── index0.ts -rw-r--r-- 1 root root 52828 Oct 13 04:47 index10.ts -rw-r--r-- 1 root root 54332 Oct 13 04:47 index11.ts -rw-r--r-- 1 root root 53392 Oct 13 04:47 index12.ts -rw-r--r-- 1 root root 52828 Oct 13 04:47 index13.ts -rw-r--r-- 1 root root 52828 Oct 13 04:47 index14.ts -rw-r--r-- 1 root root 53956 Oct 13 04:47 index15.ts -rw-r--r-- 1 root root 54144 Oct 13 04:47 index16.ts -rw-r--r-- 1 root root 52828 Oct 13 04:47 index17.ts -rw-r--r-- 1 root root 52640 Oct 13 04:47 index18.ts -rw-r--r-- 1 root root 53580 Oct 13 04:47 index19.ts -rw-r--r-- 1 root root 52828 Oct 13 04:47 index1.ts -rw-r--r-- 1 root root 53580 Oct 13 04:47 index2.ts -rw-r--r-- 1 root root 54520 Oct 13 04:47 index3.ts -rw-r--r-- 1 root root 52452 Oct 13 04:47 index4.ts -rw-r--r-- 1 root root 52640 Oct 13 04:47 index5.ts -rw-r--r-- 1 root root 53204 Oct 13 04:47 index6.ts -rw-r--r-- 1 root root 54708 Oct 13 04:47 index7.ts -rw-r--r-- 1 root root 52828 Oct 13 04:47 index8.ts -rw-r--r-- 1 root root 52828 Oct 13 04:47 index9.ts |
...
│ ├── index10.ts
│ ├── index11.ts
│ ├── index12.ts
│ ├── index13.ts
│ ├── index14.ts
│ ├── index15.ts
│ ├── index16.ts
│ ├── index17.ts
│ ├── index18.ts
│ ├── index19.ts
│ ├── index1.ts
│ ├── index2.ts
│ ├── index3.ts
│ ├── index4.ts
│ ├── index5.ts
│ ├── index6.ts
│ ├── index7.ts
│ ├── index8.ts
│ └── index9.ts
├── 2x1
│ ├── index0.ts
│ ├── index10.ts
│ ├── index11.ts
│ ├── index12.ts
│ ├── index13.ts
│ ├── index14.ts
│ ├── index15.ts
│ ├── index16.ts
│ ├── index17.ts
│ ├── index18.ts
│ ├── index19.ts
│ ├── index1.ts
│ ├── index2.ts
│ ├── index3.ts
│ ├── index4.ts
│ ├── index5.ts
│ ├── index6.ts
│ ├── index7.ts
│ ├── index8.ts
│ └── index9.ts
└── 4x3
├── index0.ts
├── index10.ts
├── index11.ts
├── index12.ts
├── index13.ts
├── index14.ts
├── index15.ts
├── index16.ts
├── index17.ts
├── index18.ts
├── index19.ts
├── index1.ts
├── index2.ts
├── index3.ts
├── index4.ts
├── index5.ts
├── index6.ts
├── index7.ts
├── index8.ts
└── index9.ts |
The minimal preloader segment duration is 2 seconds by default, and can be set in milliseconds with the following parameter
| Code Block | ||
|---|---|---|
| ||
hls_preloader_time_min=2000 |
Disabling HLS preloader
HLS preloader can be disabled if necessary, this feature is available since build 5.2.396. To disable HLS preloader, the following parameter is used
| Code Block | ||
|---|---|---|
| ||
hls_preloader_enabled=false |
...
1. Choose video clip (logo for example) 2in three aspect ratios: 16:9, 4:3, 2:1
2. Encode video to H264, add audio track to the clip, set GOP and remove B-frames using ffmpeg
| Code Block | ||||
|---|---|---|---|---|
| ||||
| Code Block | ||||
| ||||
ffmpeg -i clip16x9.mp4 -f lavfi -i anullsrc=channel_layout=mono:sample_rate=44100 -c:v h264 -g 30 -bf 0 -shortest 16x9/preloader16x9.mp4 ffmpeg -i clip4x3.mp4 -f lavfi -i anullsrc=channel_layout=mono:sample_rate=44100 -c:v h264 -g 30 -bf 0 -shortest 4x3/preloader4x3.mp4 ffmpeg -i clipclip2x1.mp4 -f lavfi -i anullsrc=channel_layout=mono:sample_rate=44100 -c:v h264 -g 30 -bf 0 -shortest preloader2x1/preloader2x1.mp4 |
3. Download and install HLS tools from Apple site
...
| Code Block | ||||
|---|---|---|---|---|
| ||||
cd 16x9 mediafilesegmenter -t 2 -B index -start-segments-with-iframe preloaderpreloader16x9.mp4 tar -cvzf preloader.tar.gz index*.ts |
This step should be repeated for all aspect ratios.
5. Make a folder for custom preloader
| Code Block | |||||||
|---|---|---|---|---|---|---|---|
| |||||||
mkdir /opt/custom_preloader mkdir /opt/custom_preloader/16x9 mkdir /opt/custom_preloader/4x3 mkdir /opt/custom_preloader/2x1 |
6. Unpack preloader segments from archive prepared on step 4
| Code Block | ||||
|---|---|---|---|---|
| ||||
cd /opt/custom_preloader/16x9 tar -xvzf ~/preloaderpreloader16x9.tar.gz |
This step should also be repeated for all aspect ratios.
7. Set custom preloader folder and duration in server settings
| Code Block | ||
|---|---|---|
| ||
hls_preloader_time_min=2000 hls_preloader_dir=/opt/custom_preloader |
Known limits
...
HLS subscription management using REST API
...