...

vod://sample.mp4

where sample.mp4 - is the name of the file that should be located in /usr/local/FlashphonerWebCallServer/media folder. Since build 5.2.687, a custom folder can specified with the following parameter in flashphoner.properties file

media_dir=/usr/local/FlashphonerWebCallServer/media

...

If a file with such a name does not exist, the server returns the StreamStatusEvent FAILED message, where the "info" field has the reason: "File not found".

A stream created this way can be displayed to one user (personal VOD). If a full-featured online-broadcast is required, provide Second viewer cannot subscribe to personal VOD stream, such stream cannot be transcoded, added to mixer or played by HLS.

If a full-featured online-broadcast is required, provide the link to a file as follows:

...

Multiple user can connect to such a stream simultaneously. VOD live stream can be transcoded, added to mixer or played by HLS.

Supported formats and codecs

...

1. The browser connects to the server via Websocket WebSocket and sends the publish command.
2. The browser captures the microphone and the camera and sends the WebRTC stream as H.264 + AAC to the server, enabling recording with the parameter record: true.
3. The WCS server records the stream to a file.
4. The browser stops publishing.
5. The second browser establishes a connection via WebsocketWebSocket, creates a stream, specifies the file name, and sends the play command.
6. The second browser receives the WebRTC stream and plays this stream on the page.

...

    stream = session.createStream(options).on(STREAM_STATUS.PENDING, function(stream) {
        ...
    }).on(STREAM_STATUS.PLAYING, function(stream) {
        ...
    }).on(STREAM_STATUS.STOPPED, function() {
        setStatus(STREAM_STATUS.STOPPED);
        onStopped();
    }).on(STREAM_STATUS.FAILED, function(stream) {
        ...
    }).on(STREAM_STATUS.NOT_ENOUGH_BANDWIDTH, function(stream){
        ...
    });
    stream.play();

Known issues

1. AAC frames of type 0 are not supported by decoder and will be ignored while stream pulled playback

In this case, warnings will be displayed in the client log:

...

...

VOD loop

VOD live translation supports VOD loop: after end of file, capturing starts from file begin. This feature is enabled with the following parameter in flashphoner.properties file

vod_live_loop=true

VOD capturing from AWS S3 or from other S3 compatible storage

VOD stream can be captured from file placed to AWS S3 storage. Comparing with VOD capture from local disk, file from external storage is downloaded and captured sequentally.

To capture VOD from AWS S3 file, specify a link to the vod file as a stream name when calling the session.createStream() function, as follows:

vod://s3/bucket/sample.mp4

where

• bucket is S3 bucket name
• sample.mp4 is file name

Since build 5.2.939 it is possible to set the full file URL in S3 storage, this allows to capture VOD from other S3 storages (Digital Ocean, Selectel etc)

Digital Ocean Spaces URL example

vod://s3/https://ams3.digitaloceanspaces.com/myspace/folder/file.mp4

Selectel URL example

vod://s3/https://s3.selcdn.ru/mystorage/file.mp4

Operation flowchart

Image Added

1. Browser requests VOD capture from AWS file

2. WCS server sends request to AWS

3. File is downloaded to WCS server

4. WebRTC stream from file is sending to browser for playback

Set up

S3 credentials configuration

AWS

To download files from AWS S3 bucket, S3 credentials must be set in flashphoner.properties file

aws_s3_credentials=zone;login;hash

Where

• zone - AWS region where bucket is placed
• login - Access Key ID
• hash - Secret Accesss Key

S3 credentials setting example:

aws_s3_credentials=eu-central-1;AA22BB33CC44DE;DhlAkpZ4adclHhbLwhTNL4hvWTo80Njo

Digital Ocean Spaces

To download files from DO Spaces set the credentials as

aws_s3_credentials=ams3;access_key;secret

Where

• ams3 - digitaloceanspaces.com subdomain
• access_key - storage access key
• secret - storage access secret code

Selectel

To download files from Selectel S3 set the credentials as

aws_s3_credentials=ru-1a;login;password

Where

• ru-1a - storage region
• login - user name
• password - password

Capturing VOD stream from file while it is downloading

To capture stream from file while it is downloading, the following parameter should be set

vod_mp4_container_new=true

If channel bandwidth between WCS and S3 storage is low, or this channel is not stable enough, file bufferization may be enabled. The buffer size is set in milliseconds with the following parameter

vod_mp4_container_new_buffer_ms=10000

In this case, buffer size is 10 seconds.

File format requirements

Header section (moov) should always be before data section (mdat). File structure should be like this:

Atom ftyp @ 0 of size: 32, ends @ 32
Atom moov @ 32 of size: 357961, ends @ 357993
...
Atom free @ 357993 of size: 8, ends @ 358001
Atom mdat @ 358001 of size: 212741950, ends @ 213099951

File structure can be checked with AtomicParsley utility

AtomicParsley file.mp4 -T 1

If the file structure does not match the requiremets, this file will not be played. Wrong file structure can be fixed if necessary with ffmpeg without reencoding

ffmpeg -i bad.mp4 -acodec copy -vcodec copy -movflags +faststart good.mp4

File name requirements

Official AWS S3 documentation does not recommend to use spaces along another special characters, but does not prohibits them. If the file name contains spaces, they should be replaced by '%20', for example

vod://s3/bucket/sample%20with%20spaces.mp4

VOD capture management with REST API

REST query should be HTTP/HTTPS POST request as:

• HTTP: http://test.flashphoner.com:8081/rest-api/vod/startup
• HTTPS: https://test.flashphoner.com:8444/rest-api/vod/startup

Where:

• test.flashphoner.com - WCS server address
• 8081 - standard REST / HTTP port
• 8444 - standard HTTPS port
• rest-api - mandatory part of URL
• /vod/startup - REST method used

REST queries and responses

{
 "uri":"vod-live://sample.mp4",
 "localStreamName": "test"
}

{
 "localStreamName": "test"
}

[
    {
        "localMediaSessionId": "29ec3236-1093-42bb-88d6-d4ac37af3ac0",
        "localStreamName": "test",
        "uri": "vod-live://sample.mp4",
        "status": "PROCESSED_LOCAL",
        "hasAudio": true,
        "hasVideo": true,
        "record": false,
        "loop": false
    }
]

[
    {
        "localMediaSessionId": "29ec3236-1093-42bb-88d6-d4ac37af3ac0",
        "localStreamName": "test",
        "uri": "vod-live://sample.mp4",
        "status": "PROCESSED_LOCAL",
        "hasAudio": true,
        "hasVideo": true,
        "record": false,
        "loop": false
    }
]

{
 "uri":"vod://sample.mp4",
 "localStreamName": "test"
}

Parameters

vod://sample.mp4

test

PROCESSED_LOCAL

29ec3236-1093-42bb-88d6-d4ac37af3ac0

true

true

false

VOD looping on demand

Since build 5.2.1528 it is possible to enable VOD looping while creating VOD live translation via REST API

{
 "uri":"vod-live://sample.mp4",
 "localStreamName": "test",
 "loop": true
}

By default, if loop parameter is not set, vod_live_loop is applied. If the parameter is set, its value is applied as follows

• true - file will be looped
• false - file will be played once, then VOD live translation will stop

The loop parameter has a precedence over vod_live_loop value.

Known limits

/rest-api/vod/startup  query can be used for VOD live translations creation only. However, find,  `find_all `and terminate  queries can be applied both to VOD and VOD live translations.

VOD stream publishing timeout after all subscribers gone off

By default, VOD stream stays published on server during 30 seconds after last subscriber gone off, if file duration exceeds this interval. This timeout can be changed with the following parameter

vod_stream_timeout=60000

In this case, VOD stream stays published during 60 seconds.

Known issues

1. AAC frames of type 0 are not supported by ffmpeg decoder and will be ignored while stream pulled playback

Symptoms: warnings in the client log:

10:13:06,815 WARN AAC - AudioProcessor-c6c22de8-a129-43b2-bf67-1f433a814ba9 Dropping AAC frame that starts with 0, 119056e500

Solution: switch to FDK AAC decoder

use_fdk_aac=true

2. Files with B-frames can be played unsmoothly, with artifacts and freezes

Symptoms: periodic freezes and artifacts while playing VOD file, warnongs in the client log

09:32:31,238 WARN 4BitstreamNormalizer - RTMP-pool-10-thread-5 It is B-frame!

Solution:  reencode this file to exclude B-frames, for example

ffmpeg -i bad.mp4 -preset ultrafast -acodec copy -vcodec h264 -g 24 -bf 0 good.mp4

3. When VOD is captured from a long-duration file, or a number of VOD streams are captured simultaneously, server process can terminate with Out of memory

Symptoms: server process terminates; "Map failed" in server log and in error*.log

19:30:53,277 ERROR DefaultMp4SampleList - Thread-34 java.io.IOException: Map failed
    at sun.nio.ch.FileChannelImpl.map(FileChannelImpl.java:940)
    at com.googlecode.mp4parser.FileDataSourceImpl.map(FileDataSourceImpl.java:62)
    at com.googlecode.mp4parser.BasicContainer.getByteBuffer(BasicContainer.java:223)
    at com.googlecode.mp4parser.authoring.samples.DefaultMp4SampleList$SampleImpl.asByteBuffer(DefaultMp4SampleList.java:204)
    at com.flashphoner.media.F.A.A.A$1.A(Unknown Source)
    at com.flashphoner.media.M.B.C.D(Unknown Source)
    at com.flashphoner.server.C.A.B.A(Unknown Source)
    at com.flashphoner.server.C.A.B.C(Unknown Source)
    at java.lang.Thread.run(Thread.java:748)
Caused by: java.lang.OutOfMemoryError: Map failed
    at sun.nio.ch.FileChannelImpl.map0(Native Method)
    at sun.nio.ch.FileChannelImpl.map(FileChannelImpl.java:937)
    ... 8 more

Event: 1743.157 Thread 0x00007fc480375000 Exception <a 'java/lang/OutOfMemoryError': Map failed> (0x00000000a1d750b0) thrown at [/HUDSON/workspace/8-2-build-linux-amd64/jdk8u161/10277/hotspot/src/share/vm/prims/jni.cpp, line 735]

Solution:

1. Increase maximum number of regions of virtual memory

sysctl -w vm.max_map_count=262144

and virtual memory amount allocated to server process by changing in /usr/local/FlashphonerWebCallServer/bin/webcallserver file the string

ulimit -n 20000

to the strings

ulimit -n 20000
ulimit -v 1000000000

2. Starting from build 5.2.57, set the following parameter

vod_mp4_container_isoparser_heap_datasource=true