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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 <nativehelper/JNIHelp.h>
31 #include "android_runtime/AndroidRuntime.h"
32 
33 
34 // ----------------------------------------------------------------------------
35 
36 using namespace android;
37 
38 
39 #define FIR_COEF(coef) (short)(0x10000 * (coef))
40 static const short fir21[] = {
41     FIR_COEF(-0.006965742326),
42     FIR_COEF(-0.008428945737),
43     FIR_COEF( 0.004241280174),
44     FIR_COEF( 0.022141096893),
45     FIR_COEF( 0.018765669437),
46     FIR_COEF(-0.009871891152),
47     FIR_COEF(-0.024842433247),
48     FIR_COEF( 0.006121772058),
49     FIR_COEF( 0.045890841611),
50     FIR_COEF( 0.021573503509),
51     FIR_COEF(-0.059681984668),
52     FIR_COEF(-0.076036275138),
53     FIR_COEF( 0.072405390275),
54     FIR_COEF( 0.308255674582),
55     FIR_COEF( 0.424321210495),
56     FIR_COEF( 0.308255674582),
57     FIR_COEF( 0.072405390275),
58     FIR_COEF(-0.076036275138),
59     FIR_COEF(-0.059681984668),
60     FIR_COEF( 0.021573503509),
61     FIR_COEF( 0.045890841611),
62     FIR_COEF( 0.006121772058),
63     FIR_COEF(-0.024842433247),
64     FIR_COEF(-0.009871891152),
65     FIR_COEF( 0.018765669437),
66     FIR_COEF( 0.022141096893),
67     FIR_COEF( 0.004241280174),
68     FIR_COEF(-0.008428945737),
69     FIR_COEF(-0.006965742326)
70 };
71 static const int nFir21 = sizeof(fir21) / sizeof(fir21[0]);
72 
73 static const int BUF_SIZE = 2048;
74 
75 
android_media_ResampleInputStream_fir21(JNIEnv * env,jclass,jbyteArray jIn,jint jInOffset,jbyteArray jOut,jint jOutOffset,jint jNpoints)76 static void android_media_ResampleInputStream_fir21(JNIEnv *env, jclass /* clazz */,
77          jbyteArray jIn,  jint jInOffset,
78          jbyteArray jOut, jint jOutOffset,
79          jint jNpoints) {
80 
81     // safety first!
82     if (nFir21 + jNpoints * 2 > BUF_SIZE) {
83         jniThrowExceptionFmt(env, "java/lang/IllegalArgumentException",
84                 "FIR+data too long %d", nFir21 + jNpoints);
85         return;
86     }
87 
88     // get input data
89     short in[BUF_SIZE];
90     env->GetByteArrayRegion(jIn, jInOffset, (jNpoints * 2 + nFir21 - 1) * 2, (jbyte*)in);
91 
92     // compute filter
93     short out[BUF_SIZE];
94     for (int i = 0; i < jNpoints; i++) {
95         long sum = 0;
96         const short* firp = &fir21[0];
97         const short* inp = &in[i * 2];
98         for (int n = nFir21; --n >= 0; ) {
99             sum += ((long)*firp++) * ((long)*inp++);
100         }
101         out[i] = (short)(sum >> 16);
102     }
103 
104     // save new values
105     env->SetByteArrayRegion(jOut, jOutOffset, jNpoints * 2, (jbyte*)out);
106 }
107 
108 // ----------------------------------------------------------------------------
109 
110 static const JNINativeMethod gMethods[] = {
111     {"fir21", "([BI[BII)V", (void*)android_media_ResampleInputStream_fir21},
112 };
113 
114 
register_android_media_ResampleInputStream(JNIEnv * env)115 int register_android_media_ResampleInputStream(JNIEnv *env)
116 {
117     const char* const kClassPathName = "android/media/ResampleInputStream";
118 
119     return AndroidRuntime::registerNativeMethods(env,
120             kClassPathName, gMethods, NELEM(gMethods));
121 }
122