android_media_ResampleInputStream.cpp revision b798689749c64baba81f02e10cf2157c747d6b46 
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 "ResampleInputStream"
19#include "utils/Log.h"
20
21#include <media/mediarecorder.h>
22#include <stdio.h>
23#include <assert.h>
24#include <limits.h>
25#include <unistd.h>
26#include <fcntl.h>
27#include <utils/threads.h>
28
29#include "jni.h"
30#include "JNIHelp.h"
31#include "android_runtime/AndroidRuntime.h"
32
33
34// ----------------------------------------------------------------------------
35
36using namespace android;
37
38
39//
40// helper function to throw an exception
41//
42static void throwException(JNIEnv *env, const char* ex, const char* fmt, int data) {
43    if (jclass cls = env->FindClass(ex)) {
44        char msg[1000];
45        sprintf(msg, fmt, data);
46        env->ThrowNew(cls, msg);
47        env->DeleteLocalRef(cls);
48    }
49}
50
51
52#define FIR_COEF(coef) (short)(0x10000 * coef)
53static const short fir21[] = {
54    FIR_COEF(-0.006965742326),
55    FIR_COEF(-0.008428945737),
56    FIR_COEF( 0.004241280174),
57    FIR_COEF( 0.022141096893),
58    FIR_COEF( 0.018765669437),
59    FIR_COEF(-0.009871891152),
60    FIR_COEF(-0.024842433247),
61    FIR_COEF( 0.006121772058),
62    FIR_COEF( 0.045890841611),
63    FIR_COEF( 0.021573503509),
64    FIR_COEF(-0.059681984668),
65    FIR_COEF(-0.076036275138),
66    FIR_COEF( 0.072405390275),
67    FIR_COEF( 0.308255674582),
68    FIR_COEF( 0.424321210495),
69    FIR_COEF( 0.308255674582),
70    FIR_COEF( 0.072405390275),
71    FIR_COEF(-0.076036275138),
72    FIR_COEF(-0.059681984668),
73    FIR_COEF( 0.021573503509),
74    FIR_COEF( 0.045890841611),
75    FIR_COEF( 0.006121772058),
76    FIR_COEF(-0.024842433247),
77    FIR_COEF(-0.009871891152),
78    FIR_COEF( 0.018765669437),
79    FIR_COEF( 0.022141096893),
80    FIR_COEF( 0.004241280174),
81    FIR_COEF(-0.008428945737),
82    FIR_COEF(-0.006965742326)
83};
84static const int nFir21 = sizeof(fir21) / sizeof(fir21[0]);
85
86static const int BUF_SIZE = 2048;
87
88
89static void android_media_ResampleInputStream_fir21(JNIEnv *env, jclass clazz,
90         jbyteArray jIn,  jint jInOffset,
91         jbyteArray jOut, jint jOutOffset,
92         jint jNpoints) {
93
94    // safety first!
95    if (nFir21 + jNpoints > BUF_SIZE) {
96        throwException(env, "java/lang/IllegalArgumentException",
97                "FIR+data too long %d", nFir21 + jNpoints);
98        return;
99    }
100
101    // get input data
102    short in[BUF_SIZE];
103    env->GetByteArrayRegion(jIn, jInOffset, (jNpoints * 2 + nFir21 - 1) * 2, (jbyte*)in);
104
105    // compute filter
106    short out[BUF_SIZE];
107    for (int i = 0; i < jNpoints; i++) {
108        long sum = 0;
109        const short* firp = &fir21[0];
110        const short* inp = &in[i * 2];
111        for (int n = nFir21; --n >= 0; ) {
112            sum += ((long)*firp++) * ((long)*inp++);
113        }
114        out[i] = (short)(sum >> 16);
115    }
116
117    // save new values
118    env->SetByteArrayRegion(jOut, jOutOffset, jNpoints * 2, (jbyte*)out);
119}
120
121// ----------------------------------------------------------------------------
122
123static JNINativeMethod gMethods[] = {
124    {"fir21", "([BI[BII)V", (void*)android_media_ResampleInputStream_fir21},
125};
126
127
128int register_android_media_ResampleInputStream(JNIEnv *env)
129{
130    const char* const kClassPathName = "android/media/ResampleInputStream";
131    jclass clazz;
132
133    clazz = env->FindClass(kClassPathName);
134    if (clazz == NULL) {
135        LOGE("Can't find %s", kClassPathName);
136        return -1;
137    }
138
139    return AndroidRuntime::registerNativeMethods(env,
140            kClassPathName, gMethods, NELEM(gMethods));
141}
142
143
144