io.vacco.libmpghip.Jframe Maven / Gradle / Ivy

package io.vacco.libmpghip;

public final class Jframe {
  public int stereo;
  /** single channel (monophonic) */
  int single;
  /** 0 = MPEG-1, 1 = MPEG-2/2.5 */
  public int lsf;
  /** 1 = MPEG-2.5, 0 = MPEG-1/2 */
  boolean mpeg25;

  int header_change;
  /** Layer */
  public int lay;
  /** 1 = CRC-16 code following header */
  boolean error_protection;

  public int bitrate_index;
  /** sample rate of decompressed audio in Hz */
  public int sampling_frequency;

  int padding;
  boolean extension;
  public int mode;
  public int mode_ext;
  boolean copyright;
  boolean original;
  int emphasis;
  /** computed framesize */
  int framesize;

  /* AF: ADDED FOR LAYER1/LAYER2 */
  int II_sblimit;
  Jal_table2[] alloc;
  int down_sample_sblimit;
  int down_sample;
  //
  final void clear() {
    stereo = 0;
    single = 0;
    lsf = 0;
    mpeg25 = false;
    header_change = 0;
    lay = 0;
    error_protection = false;
    bitrate_index = 0;
    sampling_frequency = 0;
    padding = 0;
    extension = false;
    mode = 0;
    mode_ext = 0;
    copyright = false;
    original = false;
    emphasis = 0;
    framesize = 0;

    II_sblimit = 0;
    alloc = null;
    down_sample_sblimit = 0;
    down_sample = 0;
  }

  private static final int MAX_INPUT_FRAMESIZE = 4096;
  /** decode a header and write the information into the frame structure */
  @SuppressWarnings("boxing")
  final boolean decode_header(final Jmpstr_tag mp, final int newhead) {

    if ((newhead & (1 << 20)) != 0) {
      this.lsf = (newhead & (1 << 19)) != 0 ? 0x0 : 0x1;
      this.mpeg25 = false;
    } else {
      this.lsf = 1;
      this.mpeg25 = true;
    }

    this.lay = 4 - ((newhead >>> 17) & 3);

    if (this.lay != 3 && this.mpeg25) {
      System.err.printf("MPEG-2.5 is supported by Layer3 only\n");
      return false;
    }
    if (((newhead >>> 10) & 0x3) == 0x3) {
      System.err.printf("Stream error\n");
      return false;
    }
    if (this.mpeg25) {
      this.sampling_frequency = 6 + ((newhead >>> 10) & 0x3);
    } else {
      this.sampling_frequency = ((newhead >>> 10) & 0x3) + (this.lsf * 3);
    }

    this.error_protection = ((newhead >>> 16) & 0x1) == 0; // (((newhead >>> 16) & 0x1) ^ 0x1) != 0;

    if (this.mpeg25) {
      this.bitrate_index = ((newhead >>> 12) & 0xf);
    }

    this.bitrate_index = ((newhead >>> 12) & 0xf);
    this.padding = ((newhead >>> 9) & 0x1);
    this.extension = ((newhead >>> 8) & 0x1) != 0;
    this.mode = ((newhead >>> 6) & 0x3);
    this.mode_ext = ((newhead >>> 4) & 0x3);
    this.copyright = ((newhead >>> 3) & 0x1) != 0;
    this.original = ((newhead >>> 2) & 0x1) != 0;
    this.emphasis = newhead & 0x3;

    this.stereo = (this.mode == Jmpg123.MPG_MD_MONO) ? 1 : 2;

    switch (this.lay) {
      case 1:
        this.framesize = Jmpstr_tag.tabsel_123[this.lsf][0][this.bitrate_index] * 12000;
        this.framesize /= Jmpstr_tag.freqs[this.sampling_frequency];
        this.framesize = ((this.framesize + this.padding) << 2) - 4;
        this.down_sample = 0;
        this.down_sample_sblimit = Jmpg123.SBLIMIT >> (this.down_sample);
        break;

      case 2:
        this.framesize = Jmpstr_tag.tabsel_123[this.lsf][1][this.bitrate_index] * 144000;
        this.framesize /= Jmpstr_tag.freqs[this.sampling_frequency];
        this.framesize += this.padding - 4;
        this.down_sample = 0;
        this.down_sample_sblimit = Jmpg123.SBLIMIT >> (this.down_sample);
        break;

      case 3:
        /* #if 0
        			this.do_layer = do_layer3;
        			if( this.lsf ) {
        				ssize = (this.stereo == 1) ? 9 : 17;
        			} else {
        				ssize = (this.stereo == 1) ? 17 : 32;
        			}
        #endif */

        /* #if 0
        			if( this.error_protection ) {
        				ssize += 2;
        			}
        #endif */
        if (this.framesize > MAX_INPUT_FRAMESIZE) {
          System.err.printf("Frame size too big.\n");
          this.framesize = MAX_INPUT_FRAMESIZE;
          return false;
        }

        if (this.bitrate_index == 0) {
          this.framesize = 0;
        } else {
          this.framesize = Jmpstr_tag.tabsel_123[this.lsf][2][this.bitrate_index] * 144000;
          this.framesize /= Jmpstr_tag.freqs[this.sampling_frequency] << (this.lsf);
          this.framesize = this.framesize + this.padding - 4;
        }
        break;
      default:
        System.err.printf("Sorry, layer %d not supported\n", this.lay);
        return false;
    }
    /*    print_header(mp, fr); */
    return true;
  }
}