android_media_AmrInputStream.cpp revision 15dd15fd572df6b6f785dff75f66e9b99f40322a 
1/*
2**
3** Copyright 2007, The Android Open Source Project
4**
5** Licensed under the Apache License, Version 2.0 (the "License");
6** you may not use this file except in compliance with the License.
7** You may obtain a copy of the License at
8**
9**     http://www.apache.org/licenses/LICENSE-2.0
10**
11** Unless required by applicable law or agreed to in writing, software
12** distributed under the License is distributed on an "AS IS" BASIS,
13** WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
14** See the License for the specific language governing permissions and
15** limitations under the License.
16*/
17
18#define LOG_TAG "AmrInputStream"
19#include "utils/Log.h"
20
21#include "jni.h"
22#include "JNIHelp.h"
23#include "android_runtime/AndroidRuntime.h"
24#include "gsmamr_enc.h"
25
26// ----------------------------------------------------------------------------
27
28using namespace android;
29
30// Corresponds to max bit rate of 12.2 kbps.
31static const int MAX_OUTPUT_BUFFER_SIZE = 32;
32static const int FRAME_DURATION_MS = 20;
33static const int SAMPLING_RATE_HZ = 8000;
34static const int SAMPLES_PER_FRAME = ((SAMPLING_RATE_HZ * FRAME_DURATION_MS) / 1000);
35static const int BYTES_PER_SAMPLE = 2;  // Assume 16-bit PCM samples
36static const int BYTES_PER_FRAME = (SAMPLES_PER_FRAME * BYTES_PER_SAMPLE);
37
38struct GsmAmrEncoderState {
39    GsmAmrEncoderState()
40        : mEncState(NULL),
41          mSidState(NULL),
42          mLastModeUsed(0) {
43    }
44
45    ~GsmAmrEncoderState() {}
46
47    void*   mEncState;
48    void*   mSidState;
49    int32_t mLastModeUsed;
50};
51
52static jint android_media_AmrInputStream_GsmAmrEncoderNew
53        (JNIEnv *env, jclass clazz) {
54    GsmAmrEncoderState* gae = new GsmAmrEncoderState();
55    if (gae == NULL) {
56        jniThrowRuntimeException(env, "Out of memory");
57    }
58    return (jint)gae;
59}
60
61static void android_media_AmrInputStream_GsmAmrEncoderInitialize
62        (JNIEnv *env, jclass clazz, jint gae) {
63    GsmAmrEncoderState *state = (GsmAmrEncoderState *) gae;
64    int32_t nResult = AMREncodeInit(&state->mEncState, &state->mSidState, false);
65    if (nResult != OK) {
66        jniThrowExceptionFmt(env, "java/lang/IllegalArgumentException",
67                "GsmAmrEncoder initialization failed %d", nResult);
68    }
69}
70
71static jint android_media_AmrInputStream_GsmAmrEncoderEncode
72        (JNIEnv *env, jclass clazz,
73         jint gae, jbyteArray pcm, jint pcmOffset, jbyteArray amr, jint amrOffset) {
74
75    jbyte inBuf[BYTES_PER_FRAME];
76    jbyte outBuf[MAX_OUTPUT_BUFFER_SIZE];
77
78    env->GetByteArrayRegion(pcm, pcmOffset, sizeof(inBuf), inBuf);
79    GsmAmrEncoderState *state = (GsmAmrEncoderState *) gae;
80    int32_t length = AMREncode(state->mEncState, state->mSidState,
81                                (Mode) MR122,
82                                (int16_t *) inBuf,
83                                (unsigned char *) outBuf,
84                                (Frame_Type_3GPP*) &state->mLastModeUsed,
85                                AMR_TX_WMF);
86    if (length < 0) {
87        jniThrowExceptionFmt(env, "java/io/IOException",
88                "Failed to encode a frame with error code: %d", length);
89        return -1;
90    }
91
92    // The 1st byte of PV AMR frames are WMF (Wireless Multimedia Forum)
93    // bitpacked, i.e.;
94    //    [P(4) + FT(4)]. Q=1 for good frame, P=padding bit, 0
95    // Here we are converting the header to be as specified in Section 5.3 of
96    // RFC 3267 (AMR storage format) i.e.
97    //    [P(1) + FT(4) + Q(1) + P(2)].
98    if (length > 0) {
99      outBuf[0] = (outBuf[0] << 3) | 0x4;
100    }
101
102    env->SetByteArrayRegion(amr, amrOffset, length, outBuf);
103
104    return length;
105}
106
107static void android_media_AmrInputStream_GsmAmrEncoderCleanup
108        (JNIEnv *env, jclass clazz, jint gae) {
109    GsmAmrEncoderState *state = (GsmAmrEncoderState *)gae;
110    AMREncodeExit(&state->mEncState, &state->mSidState);
111    state->mEncState = NULL;
112    state->mSidState = NULL;
113}
114
115static void android_media_AmrInputStream_GsmAmrEncoderDelete
116        (JNIEnv *env, jclass clazz, jint gae) {
117    delete (GsmAmrEncoderState*)gae;
118}
119
120// ----------------------------------------------------------------------------
121
122static JNINativeMethod gMethods[] = {
123    {"GsmAmrEncoderNew",        "()I",        (void*)android_media_AmrInputStream_GsmAmrEncoderNew},
124    {"GsmAmrEncoderInitialize", "(I)V",       (void*)android_media_AmrInputStream_GsmAmrEncoderInitialize},
125    {"GsmAmrEncoderEncode",     "(I[BI[BI)I", (void*)android_media_AmrInputStream_GsmAmrEncoderEncode},
126    {"GsmAmrEncoderCleanup",    "(I)V",       (void*)android_media_AmrInputStream_GsmAmrEncoderCleanup},
127    {"GsmAmrEncoderDelete",     "(I)V",       (void*)android_media_AmrInputStream_GsmAmrEncoderDelete},
128};
129
130
131int register_android_media_AmrInputStream(JNIEnv *env)
132{
133    const char* const kClassPathName = "android/media/AmrInputStream";
134
135    return AndroidRuntime::registerNativeMethods(env,
136            kClassPathName, gMethods, NELEM(gMethods));
137}
138