handleC1_(dtvccPacket, captionCommand, pts) {
    // Note: This decoder ignores delay and delayCancel control codes in the C1.
    // group. These control codes delay processing of data for a set amount of
    // time, however this decoder processes that data immediately.

    if (captionCommand >= 0x80 && captionCommand <= 0x87) {
      const windowNum = captionCommand & 0x07;
      this.setCurrentWindow_(windowNum);
    } else if (captionCommand === 0x88) {
      const bitmap = dtvccPacket.readByte().value;
      return this.clearWindows_(bitmap, pts);
    } else if (captionCommand === 0x89) {
      const bitmap = dtvccPacket.readByte().value;
      this.displayWindows_(bitmap, pts);
    } else if (captionCommand === 0x8a) {
      const bitmap = dtvccPacket.readByte().value;
      return this.hideWindows_(bitmap, pts);
    } else if (captionCommand === 0x8b) {
      const bitmap = dtvccPacket.readByte().value;
      return this.toggleWindows_(bitmap, pts);
    } else if (captionCommand === 0x8c) {
      const bitmap = dtvccPacket.readByte().value;
      return this.deleteWindows_(bitmap, pts);
    } else if (captionCommand === 0x8f) {
      return this.reset_(pts);
    } else if (captionCommand === 0x90) {
      this.setPenAttributes_(dtvccPacket);
    } else if (captionCommand === 0x91) {
      this.setPenColor_(dtvccPacket);
    } else if (captionCommand === 0x92) {
      this.setPenLocation_(dtvccPacket);
    } else if (captionCommand === 0x97) {
      this.setWindowAttributes_(dtvccPacket);
    } else if (captionCommand >= 0x98 && captionCommand <= 0x9f) {
      const windowNum = (captionCommand & 0x0f) - 8;
      this.defineWindow_(dtvccPacket, windowNum, pts);
    }
    return [];
  }
Processes C1 group data.
These are caption commands.
@param {!shaka.cea.DtvccPacket} dtvccPacket
@param {number} captionCommand
@param {number} pts in seconds
@return {!Array<shaka.extern.ICaptionDecoder.ClosedCaption>}
@throws {!shaka.util.Error} a possible out-of-range buffer read.
@private