AudioCodec.rar_class A

package android.net.rtp; import java.util.Arrays; /** * This class defines a collection of audio codecs to be used with * {@link AudioStream}s. Their parameters are designed to be exchanged using * Session Description Protocol (SDP). Most of the values listed here can be * found in RFC 3551, while others are described in separated standards. * * <p>Few simple configurations are defined as public static instances for the * convenience of direct uses. More complicated ones could be obtained using * {@link #getCodec(int, String, String)}. For example, one can use the * following snippet to create a mode-1-only AMR codec.</p> * <pre> * AudioCodec codec = AudioCodec.getCodec(100, "AMR/8000", "mode-set=1"); * </pre> * * @see AudioStream * @hide */ public class AudioCodec { /** * The RTP payload type of the encoding. */ public final int type; /** * The encoding parameters to be used in the corresponding SDP attribute. */ public final String rtpmap; /** * The format parameters to be used in the corresponding SDP attribute. */ public final String fmtp; /** * G.711 u-law audio codec. */ public static final AudioCodec PCMU = new AudioCodec(0, "PCMU/8000", null); /** * G.711 a-law audio codec. */ public static final AudioCodec PCMA = new AudioCodec(8, "PCMA/8000", null); /** * GSM Full-Rate audio codec, also known as GSM-FR, GSM 06.10, GSM, or * simply FR. */ public static final AudioCodec GSM = new AudioCodec(3, "GSM/8000", null); /** * GSM Enhanced Full-Rate audio codec, also known as GSM-EFR, GSM 06.60, or * simply EFR. */ public static final AudioCodec GSM_EFR = new AudioCodec(96, "GSM-EFR/8000", null); /** * Adaptive Multi-Rate narrowband audio codec, also known as AMR or AMR-NB. * Currently CRC, robust sorting, and interleaving are not supported. See * more details about these features in RFC 4867. */ public static final AudioCodec AMR = new AudioCodec(97, "AMR/8000", null); private static final AudioCodec[] sCodecs = {GSM_EFR, AMR, GSM, PCMU, PCMA}; private AudioCodec(int type, String rtpmap, String fmtp) { this.type = type; this.rtpmap = rtpmap; this.fmtp = fmtp; } /** * Returns system supported audio codecs. */ public static AudioCodec[] getCodecs() { return Arrays.copyOf(sCodecs, sCodecs.length); } /** * Creates an AudioCodec according to the given configuration. * * @param type The payload type of the encoding defined in RTP/AVP. * @param rtpmap The encoding parameters specified in the corresponding SDP * attribute, or null if it is not available. * @param fmtp The format parameters specified in the corresponding SDP * attribute, or null if it is not available. * @return The configured AudioCodec or {@code null} if it is not supported. */ public static AudioCodec getCodec(int type, String rtpmap, String fmtp) { if (type < 0 || type > 127) { return null; } AudioCodec hint = null; if (rtpmap != null) { String clue = rtpmap.trim().toUpperCase(); for (AudioCodec codec : sCodecs) { if (clue.startsWith(codec.rtpmap)) { String channels = clue.substring(codec.rtpmap.length()); if (channels.length() == 0 || channels.equals("/1")) { hint = codec; } break; } } } else if (type < 96) { for (AudioCodec codec : sCodecs) { if (type == codec.type) { hint = codec; rtpmap = codec.rtpmap; break; } } } if (hint == null) { return null; } if (hint == AMR && fmtp != null) { String clue = fmtp.toLowerCase(); if (clue.contains("crc=1") || clue.contains("robust-sorting=1") || clue.contains("interleaving=")) { return null; } } return new AudioCodec(type, rtpmap, fmtp); } }