Diagram

flowchart TB
    is("<b>MediaSocket</b>\nFile: input.wav")
    os("<b>MediaSocket</b>\nType: MpegAudio\nSubtype: MpegAudioLayer3\nFile: output.mp3")
    tr("<b>Transcoder Block</b>\nopen\nrun\nclose")
    out["output.mp3"]

    in["input.wav"]
    out["output.mp3"]

    is --> |"add input"| tr 
    os --> |"add output"| tr
    
    in  --> |"read"| tr --> |"write"| out

Code

This is the code for the output socket:

static MediaSocket CreateOutputSocket(Options opt)
{
    AudioStreamInfo asi = new AudioStreamInfo();
    asi.StreamType = StreamType.MpegAudio;
    asi.StreamSubType = StreamSubType.MpegAudioLayer3;

    // The default bitrate is 128000. You can set it to 192000, 256000, etc.
    // asi.Bitrate = 192000;

    // You can change the sampling rate and the number of the channels
    // asi.SampleRate = 44100;
    // asi.Channels = 1;

    MediaPin pin = new MediaPin();
    pin.StreamInfo = asi;

    MediaSocket socket = new MediaSocket();
    socket.StreamType = StreamType.MpegAudio;
    socket.StreamSubType = StreamSubType.MpegAudioLayer3;

    socket.Pins.Add(pin);

    // output to a file
    socket.File = opt.OutputFile;

    return socket;
}

The complete program is available on GitHub:

• enc_mp3_file

Diagram

flowchart TB
    is("<b>MediaSocket</b>\nFile: input.wav")
    os("<b>MediaSocket</b>\nType: AAC\nSubtype: AAC_ADTS\nFile: output.aac")
    tr("<b>Transcoder Block</b>\nopen\nrun\nclose")

    in["input.wav"]
    out["output.aac"]

    is --> |"add input"| tr 
    os --> |"add output"| tr
    
    in  --> |"read"| tr --> |"write"| out

Code

This is the code for the output socket:

primo::ref<MediaSocket> createOutputSocket(Options& opt)
{
    // create stream info to describe the output audio stream
    auto asi = primo::make_ref(Library::createAudioStreamInfo());
    asi->setStreamType(StreamType::MPEG_Audio);
    asi->setStreamSubType(StreamSubType::MPEG_Audio_Layer3);

    // The default bitrate is 128000. You can set it to 192000, 256000, etc.
    // asi->setBitrate(192000);

    // Optionally set the sampling rate and the number of the channels, e.g. 44.1 Khz, Mono 
    // asi->setSampleRate(44100);
    // asi->setChannels(1);

    // create a pin using the stream info 
    auto pin = primo::make_ref(Library::createMediaPin());
    pin->setStreamInfo(asi.get());

    // the pin allows you to specify additional parameters for the encoder 
    // for example, change the stereo mode, e.g. Joint Stereo
    // pin->params()->addInt(Param::Encoder::Audio::MPEG1::StereoMode, StereoMode::Joint);

    // finally create a socket for the output container format which is MP3 in this case
    auto socket = primo::make_ref(Library::createMediaSocket());
    socket->setStreamType(StreamType::MPEG_Audio);
    socket->setStreamSubType(StreamSubType::MPEG_Audio_Layer3);

    socket->pins()->add(pin.get());

    // output to a file
    auto output_file = primo::ustring(opt.outputFile);
    socket->setFile(output_file);

    return socket;
}

The complete program is available on GitHub:

• enc_aac_adts_file (macOS)
• enc_aac_adts_file (Linux)
• enc_aac_adts_file (Windows)

Diagram

flowchart TB
    is("<b>MediaSocket</b>\nFile: input.wav")
    os("<b>MediaSocket</b>\nType: MPEG_Audio\nSubtype: MPEG_Audio_Layer3\nFile: output.mp3")
    tr("<b>Transcoder Block</b>\nopen\nrun\nclose")

    in["input.wav"]
    out["output.mp3"]

    is --> |"add input"| tr 
    os --> |"add output"| tr
    
    in  --> |"read"| tr --> |"write"| out

Code

This is the code for the output socket:

primo::ref<MediaSocket> createOutputSocket(Options& opt)
{
    // create stream info to describe the output audio stream
    auto asi = primo::make_ref(Library::createAudioStreamInfo());
    asi->setStreamType(StreamType::MPEG_Audio);
    asi->setStreamSubType(StreamSubType::MPEG_Audio_Layer3);

    // The default bitrate is 128000. You can set it to 192000, 256000, etc.
    // asi->setBitrate(192000);

    // Optionally set the sampling rate and the number of the channels, e.g. 44.1 Khz, Mono 
    // asi->setSampleRate(44100);
    // asi->setChannels(1);

    // create a pin using the stream info 
    auto pin = primo::make_ref(Library::createMediaPin());
    pin->setStreamInfo(asi.get());

    // the pin allows you to specify additional parameters for the encoder 
    // for example, change the stereo mode, e.g. Joint Stereo
    // pin->params()->addInt(Param::Encoder::Audio::MPEG1::StereoMode, StereoMode::Joint);

    // finally create a socket for the output container format which is MP3 in this case
    auto socket = primo::make_ref(Library::createMediaSocket());
    socket->setStreamType(StreamType::MPEG_Audio);
    socket->setStreamSubType(StreamSubType::MPEG_Audio_Layer3);

    socket->pins()->add(pin.get());

    // output to a file
    auto output_file = primo::ustring(opt.outputFile);
    socket->setFile(output_file);

    return socket;
}

The complete program is available on GitHub:

• enc_mp3_file (macOS)
• enc_mp3_file (Linux)
• enc_mp3_file (Windows)

• Remove 32-bit application support (C++ and .NET)
• C++: Refactor API headers to use lowercase file names and subdirectories for namespaces
• .NET: New AVBlocks .NET SDK for macOS and Linux (based on .NET Core 6+)
• Distribute the AVBlocks Core and AVBlocks .NET Core through GitHub

Samples

• Use cmake and Visual Studio Code for AVBlocks samples
• GitHub repositories for AVBlocks samples
• C++: Add enc_preset_file sample
• .NET: Add enc_preset_file sample

Docs

• Split the wiki to separate C++ and .NET sites

• The MediaInfo object now implements the Block abstract interface.

Samples

• New overlay_mp4_png_file sample. This sample shows how to place a watermark on a video file by blending a video file with a PNG image.

Here are some key notes about using this parameter:

• It must be set to the output pin (see the sample code below)
• The supported values are 0 and 1. A negative value is ignored.
• MaxDecFrameBuffering(0) achieves decoding latency of 0 frames for progressive streams and 1 frame for interlaced streams.
• MaxDecFrameBuffering(1) achieves decoding latency of 1 frame both for progressive and interlaced streams.
• If the stream has B-frames (or more precisely the total number of reference frames is greater than 1) the decoding will still succeed, but decoding latency will be greater than the required one, as a safety guard.
• With MaxDecFrameBuffering (0|1) only one decoding thread is used, so it hurts performance and it must be used only when low decoding latency is the primary goal.

The following code can be used to set the MaxDecFrameBuffering parameter to an output pin:

void setH264DecodingLatency(primo::avblocks::MediaPin* pin, int32_t desiredLatency)
{
    using namespace primo::avblocks;
    using namespace primo::avblocks::Param;
    
    ParameterList* params ( Library::createParameterList() );
        IntParameter* maxDecFrameBuffering (Library::createIntParameter() );
            maxDecFrameBuffering->setName(Decoder::Video::H264::VUI::MaxDecFrameBuffering);
            maxDecFrameBuffering->setValue(desiredLatency);
            params->add(maxDecFrameBuffering);
        maxDecFrameBuffering->release();
        pin->setParams(params);
    params->release();
}

Update: This issue has been fixed as of version 1.6.

Wmvcore.dll is standard on all editions of Windows Vista and Windows 7 with the exception of the “N” editions. The “N” editions are distributed in Europe and do not include Windows Media Player and its related technologies.

The following versions of Windows Vista or Window 7 are affected:

• Windows 7 Starter N
• Windows 7 Home Premium N
• Windows 7 Professional N
• Windows 7 Ultimate N
• Windows Vista Home Basic N
• Windows Vista Business N
• Windows Vista Home Basic KN
• Windows Vista Business KN

AVBlocks depends on the following Wmvcore.dll functions for ASF muxing and demuxing:

• WMCreateProfileManager
• WMCreateSyncReader
• WMCreateWriter

We are fixing this issue by changing the code to load Wmvcore.dll on-demand. This fix will be available in AVBlocks 1.6.

When you license a Primo Software product you usually get a license file in the email. The license file is basically a signed XML string that describes the products and features you have licensed. Then you have to provide the license to AVBlocks with the Library.SetLicense method.

Here is a code snippet in C#:

const string license = 
    @"<primoSoftware>
      <license version='1.0'>
        <token>abcdefghijklmnop</token>
        <revision>1</revision>
        <issueDate>2013-05-23</issueDate>
        <expireDate>2014-05-24</expireDate>
        <updateTime>2013-05-23 21:02:44</updateTime>
        <item id='avb-win'>
          <product>avb</product>
          <feature id='h264-enc' />
          <feature id='pcm' />
        </item>    
    	<signature>abcd-long-signature-string-here</signature>
      </license>
    </primoSoftware>";
    
Library.SetLicense(license);

The license above is for AVBlocks for Windows (avb-win) and includes the AVC / H.264 Encoder (h264-enc) and PCM Audio (pcm) features.

Then the following calls should return true for the license above:

Library.IsLicensed(null, null);
Library.IsLicensed(null, "h264-enc");
Library.IsLicensed(null, "pcm");
Library.IsLicensed("avb", "h264-enc");
Library.IsLicensed("avb", "pcm");

NOTES:

1. Calling Library.SetLicense on any of the AVBlocks Demo libraries will fail. The Demo version cannot be licensed. If you downloaded AVBlocks from www.avblocks.com then you have the Demo product. You need to get your AVBlocks copy from the Downloads section of the License Manager site.

2. You should be careful when formatting the license XML as it may become invalid.

Here are the rules:

• It’s OK to reformat the blank space between the xml elements in the license (spaces, new lines) the way you wish.
• It’s also OK to substitute the double quotes with single quotes (as shown in the example above), otherwise you need to escape the double quotes.
• It’s NOT OK to reorder elements or change the letter case.

• For video streams, a semi-transparent logo is overlaid on top of each video frame.
• For audio streams, a short audio sample is mixed in the original track at random places.

The demo restrictions are removed when a valid XML license is passed to Library::setLicense API method.