SAME Encoder Fixes.txt

Bug fixes:

1) same-validator.js:

   same-validator did not correctly handle 15 minute increments for purge times
   less than one hour.

   // timespec < 1 hour must be in 15-minute increment
   if (hr < 1) return (mn % 15 === 0);

2) wav.js:

   A volume of zero was not accepted even though the documentation said
   it was a valid value:

   Added "num0" to the xtype check.

   if (!(xtype.is(volume, 'num0|int+') && volume <= 32767)) {
     paramErrors.push('volume must be integer 0 <= i <= 32767');
   }

3) same.js:

   A hyphen was missing from the end of the message. constructMessageByteArray
   modified to add "-" after sender.

   message.sender,
     '-'

4) fixtures/same.js:

   Approved by FCC December 14, 2017

   'BLU': 'Blue Alert',

5) fixtures/same.js:

   Approved by FCC July 6, 2016

   'EWW': 'Extreme Wind Warning',
   'SSA': 'Storm Surge Watch',
   'SSW': 'Storm Surge Warning',

6) wav.js:

   Changed: pack("V", sampleCount * this.params.channels * this.params.bitsPerSample / 8)

   To: pack("V", sampleCount * this.params.channels)

   This fixes a length error with iTunes where the length was reported as double
   the real length. Other players checked are fine and ignore this.

========================================================================================================================

Changes:

1) In wav.js now allow a frequency of 0 to create silence and also allow frequency to be
   an array for producing DTMF tones. Also allowing decimal frequencies such as 1562.5
   and 2083.333:

   if (xtype.is(frequency, "-arr0|aar1")) {
     for (const f of frequency) {
       if (!xtype.is(f, "num0|num+")) {
         paramErrors.push("frequency must be number >= 0");
       }
     }
   } else if (!xtype.is(frequency, "num0|num+")) {
     paramErrors.push("frequency must be number >= 0");
   }

2) In lib/same.js:

   a) added three constants:

   silence1s: [0, 1.0],
   attentionNWS: [1050, 10.0],  // 1050Hz is played for 10 seconds
   attentionEAS: [[853, 960], 10.0]  // 853Hz and 960HZ dual tone played for 10 seconds

   b) constructMessageByteArray:

   Now returns an object with the fields "msgBytes" and "header". "msgBytes" is
   the data that was originally returned by the function and "header" is the
   plain text message header that can be displayed with console.log().

   c) generateWaveData:

   Added support for repeating the header audio between 1 and 3 times (3 times is
   the EAS standard). Added support for playing either a 1050 Hz NWS tone or
   853/960 Hz EAS tone. Added support for appending the "NNNN" end-of-message trailer.

   SAME.generateWaveData = function (byteArray, headerCount, attentionTone = undefined, tail = false) {
     const volume = 4096;
     const wav = new Wav({
       channels: 2,
       sampleRate: 44100,
       bitsPerSample: 16
     });

     this.encodeByteArray(wav, byteArray, volume, headerCount);

     if (attentionTone) {
       // Add an EAS or NWS attention tone at the end if requested.
       wav.append.apply(wav, [attentionTone[0], attentionTone[1], volume]);
       // Add a one second of silence with 0Hz and zero volume
       wav.append.apply(wav, [this.constants.silence1s[0], this.constants.silence1s[1], 0]);
     }

     // Append the EOM signal to the end of the message which consists of the
     // preamble followed by "NNNN".
     if (tail) {
       byteArray = this.constants.EOM
         .split("")
         .map((c) => {
           return c.charCodeAt(0);
         });

       this.encodeByteArray(wav, byteArray, volume, headerCount);
     }

     return wav.render();
   };

3) Removed need to have a "node_modules/lib" directory. All references to "lib"
   are now in the "same-encoder" directory. Installing same-encoder on Windows
   systems was problematic with trying to create symlinks to lib during
   installation.

4) Now supports multiple regions through an array of region objects consisting
   of "subdiv", "stateCode" and "countyCode" properties. This fixes open issue #1
   but breaks backward compatibility with older versions.

5) Sender value is automatically padded if less than 8 characters. Fixes open
   issue #4.

6) New "encode2" function created to support additional functionality. Original
   "encode" function works the same as it did except it includes the various
   fixes. The multiple regions array support breaks backward compatibility with
   this function but is the only break.

  /**
   * Encode a correctly formed SAME message, specified as an object, into a .wav
   * file. Provides options for header repeat count and an attention tone. Returns
   * an object containing the wav data and the header string.
   *
   * @param {Object} message SAME message object.
   * @param {number} headerCount number of times to repeat SAME header audio (default: 3)
   * @param {Array<number>} attentionTone frequency and length definition for attention tone to play. Undefined for no tone.
   * @param {boolean} tail append the message tail "NNNN" (EOM) to the end (default: false)
   * @returns {Object} An object containing wav data (wavData) and header (header) string.
   */
  SAME.encode2 = function (message, headerCount, attentionTone, tail) {...

  /**
   * Encode a correctly formed SAME message, specified as an object, into a .wav file.
   *
   * @param {Object} message SAME message object.
   * @returns {string} A fully rendered SAME message in RIFF WAVE format.
   */
  SAME.encode = function (message) {
    return SAME.encode2(message, 1).waveData;
  };