RTP: refactor native audio codec.
Change-Id: Ie4e09e221c71e3b7d7ec48fbb897335f8048181c
diff --git a/src/jni/rtp_jni/AudioCodec.cpp b/src/jni/rtp_jni/AudioCodec.cpp
new file mode 100644
index 0000000..ddd07fc
--- /dev/null
+++ b/src/jni/rtp_jni/AudioCodec.cpp
@@ -0,0 +1,161 @@
+/*
+ * Copyrightm (C) 2010 The Android Open Source Project
+ *
+ * Licensed under the Apache License, Version 2.0 (the "License");
+ * you may not use this file except in compliance with the License.
+ * You may obtain a copy of the License at
+ *
+ * http://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an "AS IS" BASIS,
+ * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ * See the License for the specific language governing permissions and
+ * limitations under the License.
+ */
+
+#include <string.h>
+
+#include "AudioCodec.h"
+
+namespace {
+
+int8_t gExponents[128] = {
+ 0, 1, 2, 2, 3, 3, 3, 3, 4, 4, 4, 4, 4, 4, 4, 4,
+ 5, 5, 5, 5, 5, 5, 5, 5, 5, 5, 5, 5, 5, 5, 5, 5,
+ 6, 6, 6, 6, 6, 6, 6, 6, 6, 6, 6, 6, 6, 6, 6, 6,
+ 6, 6, 6, 6, 6, 6, 6, 6, 6, 6, 6, 6, 6, 6, 6, 6,
+ 7, 7, 7, 7, 7, 7, 7, 7, 7, 7, 7, 7, 7, 7, 7, 7,
+ 7, 7, 7, 7, 7, 7, 7, 7, 7, 7, 7, 7, 7, 7, 7, 7,
+ 7, 7, 7, 7, 7, 7, 7, 7, 7, 7, 7, 7, 7, 7, 7, 7,
+ 7, 7, 7, 7, 7, 7, 7, 7, 7, 7, 7, 7, 7, 7, 7, 7,
+};
+
+//------------------------------------------------------------------------------
+
+class UlawCodec : public AudioCodec
+{
+public:
+ bool set(int sampleRate, int sampleCount) {
+ mSampleCount = sampleCount;
+ return sampleCount > 0;
+ }
+ int encode(void *payload, int16_t *samples);
+ int decode(int16_t *samples, void *payload, int length);
+private:
+ int mSampleCount;
+};
+
+int UlawCodec::encode(void *payload, int16_t *samples)
+{
+ int8_t *ulaws = (int8_t *)payload;
+ for (int i = 0; i < mSampleCount; ++i) {
+ int sample = samples[i];
+ int sign = (sample >> 8) & 0x80;
+ if (sample < 0) {
+ sample = -sample;
+ }
+ sample += 132;
+ if (sample > 32767) {
+ sample = 32767;
+ }
+ int exponent = gExponents[sample >> 8];
+ int mantissa = (sample >> (exponent + 3)) & 0x0F;
+ ulaws[i] = ~(sign | (exponent << 4) | mantissa);
+ }
+ return mSampleCount;
+}
+
+int UlawCodec::decode(int16_t *samples, void *payload, int length)
+{
+ int8_t *ulaws = (int8_t *)payload;
+ for (int i = 0; i < length; ++i) {
+ int ulaw = ~ulaws[i];
+ int exponent = (ulaw >> 4) & 0x07;
+ int mantissa = ulaw & 0x0F;
+ int sample = (((mantissa << 3) + 132) << exponent) - 132;
+ samples[i] = (ulaw < 0 ? -sample : sample);
+ }
+ return length;
+}
+
+AudioCodec *newUlawCodec()
+{
+ return new UlawCodec;
+}
+
+//------------------------------------------------------------------------------
+
+class AlawCodec : public AudioCodec
+{
+public:
+ bool set(int sampleRate, int sampleCount) {
+ mSampleCount = sampleCount;
+ return sampleCount > 0;
+ }
+ int encode(void *payload, int16_t *samples);
+ int decode(int16_t *samples, void *payload, int length);
+private:
+ int mSampleCount;
+};
+
+int AlawCodec::encode(void *payload, int16_t *samples)
+{
+ int8_t *alaws = (int8_t *)payload;
+ for (int i = 0; i < mSampleCount; ++i) {
+ int sample = samples[i];
+ int sign = (sample >> 8) & 0x80;
+ if (sample < 0) {
+ sample = -sample;
+ }
+ if (sample > 32767) {
+ sample = 32767;
+ }
+ int exponent = gExponents[sample >> 8];
+ int mantissa = (sample >> (exponent == 0 ? 4 : exponent + 3)) & 0x0F;
+ alaws[i] = (sign | (exponent << 4) | mantissa) ^ 0xD5;
+ }
+ return mSampleCount;
+}
+
+int AlawCodec::decode(int16_t *samples, void *payload, int length)
+{
+ int8_t *alaws = (int8_t *)payload;
+ for (int i = 0; i < length; ++i) {
+ int alaw = alaws[i] ^ 0x55;
+ int exponent = (alaw >> 4) & 0x07;
+ int mantissa = alaw & 0x0F;
+ int sample = (exponent == 0 ? (mantissa << 4) + 8 :
+ ((mantissa << 3) + 132) << exponent);
+ samples[i] = (alaw < 0 ? sample : -sample);
+ }
+ return length;
+}
+
+AudioCodec *newAlawCodec()
+{
+ return new AlawCodec;
+}
+
+struct AudioCodecType {
+ const char *name;
+ AudioCodec *(*create)();
+} gAudioCodecTypes[] = {
+ {"PCMA", newAlawCodec},
+ {"PCMU", newUlawCodec},
+ {NULL, NULL},
+};
+
+} // namespace
+
+AudioCodec *newAudioCodec(const char *codecName)
+{
+ AudioCodecType *type = gAudioCodecTypes;
+ while (type->name != NULL) {
+ if (strcmp(codecName, type->name) == 0) {
+ return type->create();
+ }
+ ++type;
+ }
+ return NULL;
+}
diff --git a/src/jni/rtp_jni/AudioCodec.h b/src/jni/rtp_jni/AudioCodec.h
new file mode 100644
index 0000000..797494c
--- /dev/null
+++ b/src/jni/rtp_jni/AudioCodec.h
@@ -0,0 +1,36 @@
+/*
+ * Copyrightm (C) 2010 The Android Open Source Project
+ *
+ * Licensed under the Apache License, Version 2.0 (the "License");
+ * you may not use this file except in compliance with the License.
+ * You may obtain a copy of the License at
+ *
+ * http://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an "AS IS" BASIS,
+ * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ * See the License for the specific language governing permissions and
+ * limitations under the License.
+ */
+
+#include <stdint.h>
+
+#ifndef __AUDIO_CODEC_H__
+#define __AUDIO_CODEC_H__
+
+class AudioCodec
+{
+public:
+ virtual ~AudioCodec() {}
+ // Returns true if initialization succeeds.
+ virtual bool set(int sampleRate, int sampleCount) = 0;
+ // Returns the length of payload in bytes.
+ virtual int encode(void *payload, int16_t *samples) = 0;
+ // Returns the number of decoded samples.
+ virtual int decode(int16_t *samples, void *payload, int length) = 0;
+};
+
+AudioCodec *newAudioCodec(const char *codecName);
+
+#endif