...

    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();

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

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

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

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

aws_s3_credentials=zone;login;hash

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

vod_mp4_container_new=true

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

Wrong file structure can be fixed if necessary with ffmpeg without reencoding

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

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

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

Parameters

vod://sample.mp4

test

PROCESSED_LOCAL

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

true

true

false

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, server process can terminate with Out of memory in case of exceeding maximum number of regions of virtual memory (vm.max_map_count)

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: increase maximum number of regions of virtual memory

sysctl -w vm.max_map_count=262144