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