Android Open Source - cameraMediaCodec Avc Utils

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License

The source code is released under:

Copyright (c) 2014, Zhang Ziyue All rights reserved. Redistribution and use in source and binary forms, with or without modification, are permitted provided that the following conditions are met: * ...

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Java Source Code

package com.android.testtool;
//from   www  .  j  a v a2  s .com
import java.nio.ByteBuffer;

import android.util.Log;


public class AvcUtils {
  
  public static final int R_BUFFER_OK = 0;
  public static final int R_TRY_AGAIN_LATER = -1;
  public static final int R_OUTPUT_UPDATE = -2;
  public static final int R_INVALID_STATE = -3;
  public static final int R_INVALIDATE_BUFFER_SIZE = -10;
  public static final int R_UNKNOWN = -40;
  
  public static final int START_PREFIX_CODE = 0x00000001;
  public static final int START_PREFIX_LENGTH = 4;
  public static final int NAL_UNIT_HEADER_LENGTH = 1;
  public static final int NAL_TYPE_UNSPECIFY        = 0x00;
  public static final int NAL_TYPE_CODED_SLICE       = 0x01;
  public static final int NAL_TYPE_CODED_SLICE_IDR     = 0x05;
  public static final int NAL_TYPE_SEI           = 0x06;
  public static final int NAL_TYPE_SPS           = 0x07;
  public static final int NAL_TYPE_PPS           = 0x08;
  public static final int NAL_TYPE_SUBSET_SPS       = 0x0f;
  
  public static boolean goToPrefix(final ByteBuffer buffer)
  {
    int presudo_prefix = 0xffffffff;
    while(buffer.hasRemaining())
    {
      presudo_prefix = (presudo_prefix << 8) | (buffer.get() & 0xff);
      if (presudo_prefix == START_PREFIX_CODE)
      {
        return true;
      }
    }
    return false;
  }
  
  public static int getNalType(final ByteBuffer buffer)
  {
    return buffer.get() & 0x1f;
  }
  
  public static int getGolombUE(final BitBufferLite bitb) {
    int leadingZeroBits = 0;
    while (!bitb.getBit()) {
      leadingZeroBits++;
    }
    final int suffix = bitb.getBits(leadingZeroBits);
    final int minimum = (1 << leadingZeroBits) - 1;
    return minimum + suffix;
  }
  
  //TODO: need support extra profile_idc and pic_order_cnt_type
  //usage: int[] width = new int[1];
  //sps should contains 00 00 00 01 67 ......
  public static void parseSPS(/*in*/byte[] sps, /*out*/int[] width, /*out*/int[] height)  //sps buffer doesn't include nal-type byte
  {
    ByteBuffer byteb = ByteBuffer.wrap(sps);
    if (false == goToPrefix(byteb) || NAL_TYPE_SPS != getNalType(byteb))
      return;
    
    BitBufferLite bitb = new BitBufferLite(byteb);
    
    int profile_idc = bitb.getBits(8);        //profile idc
    bitb.getBits(16);                //constraint_set0...,
    getGolombUE(bitb);
    if (profile_idc == 100 || profile_idc == 110 || profile_idc == 122
      || profile_idc == 244 || profile_idc == 44 || profile_idc == 83
      || profile_idc == 86 || profile_idc == 118 || profile_idc == 128) 
    {
      Log.e("AvcUtils", "SPS parsing do not support such profile idc, "+profile_idc);
      throw new UnsupportedOperationException("Profile idc NOT supported yet.");
    }
    int log2_max_frame_num_minus4 = getGolombUE(bitb);
    int pic_order_cnt_type = getGolombUE(bitb);
    if (pic_order_cnt_type == 0)
    {
      int log2_max_pic_order_cnt_lsb_minus4 = getGolombUE(bitb);
    }
    else if (pic_order_cnt_type == 1)
    {
      Log.e("AvcUtils", "SPS parsing do not support such pic_order_cnt_type, "+pic_order_cnt_type);
      throw new UnsupportedOperationException("pic_order_cnt_type NOT supported yet.");
    }
    else
    {
      //pic_order_cnt_type shall be "2", do nothing
    }
    
    int num_ref_frames = getGolombUE(bitb);
    int gaps_in_frame_num_value_allowed_flag = bitb.getBits(1);  //1 bit
    
    //KEY POINT
    int pic_width_in_mbs_minus1 = getGolombUE(bitb);
    width[0] = (pic_width_in_mbs_minus1 + 1) * 16;
    int pic_height_in_map_units_minus1 = getGolombUE(bitb);
    height[0] = (pic_height_in_map_units_minus1 + 1) * 16;
    
    //over
    return;
  }
}

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