Dalam tulisan kali ini saya akan sedikit mengulas aplikasi GlassCOder – Audio Encoder yang minimalis dan saat ini hanya berjalan di OS Linux. Untuk rekan rekan yang suka ngoprek linux, bisa mencobanya.

Aplikasi ini sudah support beberapa format Audio :

MPEG-1/1.5 Layer 2 (‘MP2’), MPEG-1/1.5 Layer 3 (‘MP3’), MPEG-4 Advanced Audio Coding, High Efficiency Profile (‘HE-AAC+’), Ogg Opus, Ogg Vorbis

Untuk saat ini GlassCoder belum memiliki interface GUI, semua masih berbasisi command line, namun bagi yang suka ngoprek dan coding, bisa membuat script sendiri untuk ngontrol aplikasi nya. Aplikasi ini bisa mengirimkan audio ke Icecast, Shoutcast atau post dalam bentuk format HTTP Live Streams [HLS].

Berikut saya sertakan OPTION yang ada dalam DOC GlassCoder

DEVICE OPTIONS

       Advanced Linux Sound Architecture (--audio-device=ALSA)

           --alsa-device=dev
               The name of the ALSA device to use. If no --audio-device option is given, then the
               hw:0 device will be used.

       Direct File Streaming (--audio-device=FILE)

           --file-name=name
               The name of the file to stream. If no --file-name option is given, then the name
               of the file will be read from standard input.

       The Jack Audio Connection Kit (--audio-device=JACK)

           --jack-client-name=name
               The name of the JACK client to use. Default is glasscoder.

           --jack-gain=gain
               Apply a fixed gain of gain dB before encoding. Default is 0 dB.

           --jack-server-name=name
               The name of the JACK server instance to use.

SUPPORTED URL SCHEMES

       Not all URL schemes are supported by all server types. The following chart breaks down the
       options.

       Table 1. Supported URL Schemes by Server Type
       ┌──────────────┬───────────┬───────────┬──────────┐
       │ Server Type  │  FILE://  │ HTTP://   │ SFTP://  │
       ├──────────────┼───────────┼───────────┼──────────┤
       │FILE          │    Yes    │    No     │    No    │
       ├──────────────┼───────────┼───────────┼──────────┤
       │FILEARCHIVE   │    Yes    │    No     │    No    │
       ├──────────────┼───────────┼───────────┼──────────┤
       │HLS           │    Yes    │ Yes [1]   │ Yes [3]  │
       ├──────────────┼───────────┼───────────┼──────────┤
       │IceCast2      │    No     │ Yes [2]   │    No    │
       ├──────────────┼───────────┼───────────┼──────────┤
       │IceOut        │    No     │   Yes     │    No    │
       ├──────────────┼───────────┼───────────┼──────────┤
       │IceStreamer   │    No     │   Yes     │    No    │
       ├──────────────┼───────────┼───────────┼──────────┤
       │Shout1        │    No     │ Yes [2]   │    No    │
       ├──────────────┼───────────┼───────────┼──────────┤
       │Shout2        │    No     │ Yes [2]   │    No    │
       ├──────────────┴───────────┴───────────┴──────────┤
       │[1] Utilizes the HTTP PUT and DELETE methods     │
       ├─────────────────────────────────────────────────┤
       │[2] Utilizes the HTTP GET method                 │
       ├─────────────────────────────────────────────────┤
       │[3] Supports ssh(1) password authentication only │
       └─────────────────────────────────────────────────┘

METADATA

       GlassCoder supports the notion of two types of metadata: "channel-based" metadata, which
       applies to the stream as a whole and does not change for the duration of an encoding
       session; and "timed" metadata, which can be changed in synchronization with the content of
       the audio stream. Channel-based metadata can be specified by means of options given to
       glasscoder(1) and will be covered in detail in the sections devoted to specific server
       types (below).

       The primary mechanism for supplying timed metadata in GlassCoder is by means of a JSON
       document containing the desired metadata, sent to the target glasscoder(1) instance at the
       port specified by the --metadata-port option by means of an HTTP POST operation. The basic
       format of the JSON document is as follows:

           {
                "Metadata": {
                     "Field1": "Some value",
                     "Field2": "Some other value"
                }
           }

       Not all server types support metadata, and those that do utilize wildly different schemas.
       Following is a breakdown of the available metadata options by server type:

   IceCast2
       Channel Metadata
           IceCast2 supports the following channel metadata fields:

           Name
               Specified by the --stream-name option.

           Description
               Specified by the --stream-description option.

           URL
               Should be a link to content related to the stream. Specified by the --stream-url
               option.

           Genre
               Should be a single word describing the nature of the stream content. Specified by
               the --stream-genre option.

       Timed Metadata
           IceCast2 provides one field of text, called StreamTitle, which can be dynamically
           updated to reflect the content currently playing on the stream. By convention, this is
           usually formatted as 'Artist - Title' on streams containing musical content.

           For example, to set the StreamTitle field to The Beatles - Hey Jude, the following
           JSON could be used:

               {
                    "Metadata": {
                         "StreamTitle": "The Beatles - Hey Jude"
                    }
               }

       Legacy Interface
           In addition to the primary JSON interface, the StreamTitle can be set by sending an
           HTTP GET request to a running glasscoder(1) instance, using the TCP port specified in
           the --metadata-port=port option. The request must be in the following format:

               http://hostname:tcp-port/admin/metadata?mount=mount-point&mode=updinfo&song=string

           Where:

           hostname - The hostname or IP address of the system running glasscoder(1)

           tcp-port - The TCP port number specified in the --metadata-port option to
           glasscoder(1)

           mount-point - The mountpoint of the stream

           string - The string to set, encoded as specified in Section 2 of RFC3986

           For example, to set a string of "The Beatles - Hey Jude" via a glasscoder(1) instance
           running at encoder.example.com with a --metadata-port value of 1234 for a mountpoint
           of MyStream, the URL would be:

            http://encoder.example.com:1234/admin/metadata?mount=MyStream&mode=updinfo&song=The%20Beatles%20-%20Hey%20Jude

   ShoutCast
       Channel Metadata
           ShoutCast supports the following channel metadata fields:

           Name
               Specified by the --stream-name option.

           URL
               Should be a link to content related to the stream. Specified by the --stream-url
               option.

           Genre
               Should be a single word describing the nature of the stream content. Specified by
               the --stream-genre option.

           ICQ ID
               Should be User Identification Number for an ICQ user associated with the stream
               content. Specified by the --stream-icq option.

           AOL Instant Messenger ID
               Should be an ID for an AOL Instant Messenger user associated with the stream
               content. Specified by the --stream-aim option.

           IRC ID
               Should be an ID for an Internet Relay Chat channel associated with the stream
               content. Specified by the --stream-irc option.

       Timed Metadata
           ShoutCast provides two fields of text which can be dynamically updated to reflect the
           content currently playing on the stream, called StreamTitle and StreamUrl. By
           convention, the StreamTitle is usually formatted as 'Artist - Title' on streams
           containing musical content, while StreamUrl is used to provide a URL whence stream
           specific content --e.g. album cover art -- can be retrieved.

           For example, to set the StreamTitle field to The Beatles - Hey Jude and the StreamUrl
           field to http://images.example.com/1234.png, the following JSON could be used:

               {
                    "Metadata": {
                         "StreamTitle": "The Beatles - Hey Jude",
                         "StreamUrl": "http://images.example.com/1234.png"
                    }
               }

               Note
               The use of either of these fields is optional in any given metadata update. If
               only one field is given, the other will remain unchanged.

       Legacy Interface
           In addition to the primary JSON interface, the StreamTitle and StreamUrl fields can be
           set by sending an HTTP GET request to a running glasscoder(1) instance, using the TCP
           port specified in the --metadata-port=port option. The request must be in the
           following format:

               http://hostname:tcp-port/admin.cgi?pass=password&mode=updinfo&song=stream-title&url=stream-url

           Where:

           hostname - The hostname or IP address of the system running glasscoder(1)

           tcp-port - The TCP port number specified in the --metadata-port option to
           glasscoder(1)

           password - The ShoutCast password, encoded as specified in Section 2 of RFC3986

           stream-title - The string to set for StreamTitle, encoded as specified in Section 2 of
           RFC3986

           stream-url - The string to set for StreamUrl, encoded as specified in Section 2 of
           RFC3986

           For example, to set a StreamTitle of "The Beatles - Hey Jude" and a StreamUrl of
           "http://image.example.com/1234.png" with a password of "MyPassword" via a
           glasscoder(1) instance running at encoder.example.com with a --metadata-port value of
           1234, the URL would be:

            http://encoder.example.com:1234/admin.cgi?pass=MyPassword&mode=updinfo&song=The%20Beatles%20-%20Hey%20Jude&url=http://image.example.com/1234.png

   HTTP Live Streams (HLS)
       Timed Metadata
           HLS supports timed metadata in the form of embedded ID3v2.4 tags. Available fields
           thus include the entire set of text tags defined in the ID3v2.4 frame specification
           (available at http://id3.org/id3v2.4.0-frames).

           For example, a typical metadata update could use the following JSON:

               {
                    "Metadata": {
                         "TIT2": "Hey Jude",
                         "TPE1": "The Beatles",
                         "TALB": "The White Album",
                         "TRSO": "WXYZ Radio"
                    }
               }

           A user defined text information frame (TXXX) can be sent by using the following
           special notation for the field identifier:

           TXXXdesc

           Where:

           desc - The TXXX Description string (see Section 4.2.6 of the ID3v2.4 Frame
           Specification)

           For example:

               {
                    "Metadata": {
                         "TIT2": "Hey Jude",
                         "TPE1": "The Beatles",
                         "TALB": "The White Album",
                         "TRSO": "WXYZ Radio",
                         "TXXXxyz": "TXXX frame with a description string of \"xyz\""
                    }
               }

NOTES

       The Debian version of GlassCoder does not support the MPEG-4 HE-AAC+ encoding, as it is
       non-free. The AudioScience HPI source device is excluded for the same reason.

BUGS

       SFTP:// transfers are done in "insecure" mode (due to crippled support for ssh(1) host
       keys in curl(1)).

       ssh(1) public key authentication is unsupported (due to crippled support for ed25519 keys
       in curl(1)).

       Ogg metadata support is still missing.

Oke…, mudah mudahan tulisan ini bisa bermanfaat.