RTP: Enable AMR codec. (f88fc1fa) · Commits · e / os / android_frameworks_base

voip/java/android/net/rtp/AudioCodec.java

+1 −2

Original line number	Diff line number	Diff line
		@@ -80,8 +80,7 @@ public class AudioCodec {
		*/
		public static final AudioCodec AMR = new AudioCodec(97, "AMR/8000", null);

		// TODO: add rest of the codecs when the native part is done.
		private static final AudioCodec[] sCodecs = {GSM_EFR, GSM, PCMU, PCMA};
		private static final AudioCodec[] sCodecs = {GSM_EFR, AMR, GSM, PCMU, PCMA};

		private AudioCodec(int type, String rtpmap, String fmtp) {
		this.type = type;

voip/jni/rtp/AmrCodec.cpp

+171 −0

Original line number	Diff line number	Diff line
		@@ -14,6 +14,8 @@
		* limitations under the License.
		*/

		#include <string.h>

		#include "AudioCodec.h"

		#include "gsmamr_dec.h"
		@@ -21,6 +23,170 @@

		namespace {

		const int gFrameBits[8] = {95, 103, 118, 134, 148, 159, 204, 244};

		//------------------------------------------------------------------------------

		// See RFC 4867 for the encoding details.

		class AmrCodec : public AudioCodec
		{
		public:
		AmrCodec() {
		if (AMREncodeInit(&mEncoder, &mSidSync, false)) {
		mEncoder = NULL;
		}
		if (GSMInitDecode(&mDecoder, (Word8 *)"RTP")) {
		mDecoder = NULL;
		}
		}

		~AmrCodec() {
		if (mEncoder) {
		AMREncodeExit(&mEncoder, &mSidSync);
		}
		if (mDecoder) {
		GSMDecodeFrameExit(&mDecoder);
		}
		}

		int set(int sampleRate, const char *fmtp);
		int encode(void payload, int16_t samples);
		int decode(int16_t samples, void payload, int length);

		private:
		void *mEncoder;
		void *mSidSync;
		void *mDecoder;

		int mMode;
		int mModeSet;
		bool mOctetAligned;
		};

		int AmrCodec::set(int sampleRate, const char *fmtp)
		{
		// These parameters are not supported.
		if (strcasestr(fmtp, "crc=1") \|\| strcasestr(fmtp, "robust-sorting=1") \|\|
		strcasestr(fmtp, "interleaving=")) {
		return -1;
		}

		// Handle mode-set and octet-align.
		char *modes = strcasestr(fmtp, "mode-set=");
		if (modes) {
		mMode = 0;
		mModeSet = 0;
		for (char c = modes; c && c != ' '; c = ++modes) {
		if (c >= '0' && c <= '7') {
		int mode = c - '0';
		if (mode > mMode) {
		mMode = mode;
		}
		mModeSet \|= 1 << mode;
		}
		}
		} else {
		mMode = 7;
		mModeSet = 0xFF;
		}
		mOctetAligned = (strcasestr(fmtp, "octet-align=1") != NULL);

		// TODO: handle mode-change-*.

		return (sampleRate == 8000 && mEncoder && mDecoder) ? 160 : -1;
		}

		int AmrCodec::encode(void payload, int16_t samples)
		{
		unsigned char bytes = (unsigned char )payload;
		Frame_Type_3GPP type;

		int length = AMREncode(mEncoder, mSidSync, (Mode)mMode,
		samples, bytes + 1, &type, AMR_TX_WMF);

		if (type != mMode \|\| length != (8 + gFrameBits[mMode] + 7) >> 3) {
		return -1;
		}

		if (mOctetAligned) {
		bytes[0] = 0xF0;
		bytes[1] = (mMode << 3) \| 0x04;
		++length;
		} else {
		// CMR = 15 (4-bit), F = 0 (1-bit), FT = mMode (4-bit), Q = 1 (1-bit).
		bytes[0] = 0xFF;
		bytes[1] = 0xC0 \| (mMode << 1) \| 1;

		// Shift left 6 bits and update the length.
		bytes[length + 1] = 0;
		for (int i = 0; i <= length; ++i) {
		bytes[i] = (bytes[i] << 6) \| (bytes[i + 1] >> 2);
		}
		length = (10 + gFrameBits[mMode] + 7) >> 3;
		}
		return length;
		}

		int AmrCodec::decode(int16_t samples, void payload, int length)
		{
		unsigned char bytes = (unsigned char )payload;
		Frame_Type_3GPP type;
		if (length < 2) {
		return -1;
		}
		int request = bytes[0] >> 4;

		if (mOctetAligned) {
		if ((bytes[1] & 0xC4) != 0x04) {
		return -1;
		}
		type = (Frame_Type_3GPP)(bytes[1] >> 3);
		if (length != (16 + gFrameBits[type] + 7) >> 3) {
		return -1;
		}
		length -= 2;
		bytes += 2;
		} else {
		if ((bytes[0] & 0x0C) \|\| !(bytes[1] & 0x40)) {
		return -1;
		}
		type = (Frame_Type_3GPP)((bytes[0] << 1 \| bytes[1] >> 7) & 0x07);
		if (length != (10 + gFrameBits[type] + 7) >> 3) {
		return -1;
		}

		// Shift left 2 bits and update the length.
		--length;
		for (int i = 1; i < length; ++i) {
		bytes[i] = (bytes[i] << 2) \| (bytes[i + 1] >> 6);
		}
		bytes[length] <<= 2;
		length = (gFrameBits[type] + 7) >> 3;
		++bytes;
		}

		if (AMRDecode(mDecoder, type, bytes, samples, MIME_IETF) != length) {
		return -1;
		}

		// Handle CMR
		if (request < 8 && request != mMode) {
		for (int i = request; i >= 0; --i) {
		if (mModeSet & (1 << i)) {
		mMode = request;
		break;
		}
		}
		}

		return 160;
		}

		//------------------------------------------------------------------------------

		// See RFC 3551 for the encoding details.

		class GsmEfrCodec : public AudioCodec
		{
		public:
		@@ -91,6 +257,11 @@ int GsmEfrCodec::decode(int16_t samples, void payload, int length)

		} // namespace

		AudioCodec *newAmrCodec()
		{
		return new AmrCodec;
		}

		AudioCodec *newGsmEfrCodec()
		{
		return new GsmEfrCodec;

voip/jni/rtp/AudioCodec.cpp

+2 −0

Original line number	Diff line number	Diff line
		@@ -21,6 +21,7 @@
		extern AudioCodec *newAlawCodec();
		extern AudioCodec *newUlawCodec();
		extern AudioCodec *newGsmCodec();
		extern AudioCodec *newAmrCodec();
		extern AudioCodec *newGsmEfrCodec();

		struct AudioCodecType {
		@@ -30,6 +31,7 @@ struct AudioCodecType {
		{"PCMA", newAlawCodec},
		{"PCMU", newUlawCodec},
		{"GSM", newGsmCodec},
		{"AMR", newAmrCodec},
		{"GSM-EFR", newGsmEfrCodec},
		{NULL, NULL},
		};