media and camera框架之四:Audio Capture

本文介绍如何使用Android的MediaRecorder接口进行音频录制及播放。通过简单的步骤,如创建MediaRecorder实例、设置音频源、配置输出格式等,可以实现音频的捕获与回放功能。

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Android 多媒体框架包含对捕获和编码多种音频格式文件的支持,因此你可以很轻松地把声音集成到你的应用程序中。如果设备硬件支持,你可以使用MediaRecorder接口编码音频文件。

这篇文档向你展示了如何实现一个从设备麦克风捕获音频,保存音频且播放音频的应用程序。

注意:Android模拟器没有捕获音频的能力,但是真机很可能提供这些功能。


演示音频捕获

从设备上捕获音频比音频和视频的播放要复杂点,但是也相当简单:

1,创建android.media.MediaRecorder一个新实例。

2,使用MediaRecorder.setAudioSource()设置音频源。你可能也许想使用MediaRecorder.AudioSource.MIC来实现。

3,使用MediaRecorder.setOutputFormat()设置输出音频文件。

4,使用MediaRecorder.setAudioEncorder()设置音频编码。

5,MediaRecorder实例调用MediaRecorder.prepare()。

6,调用MediaRecorder.start()开始捕获音频。

7,调用MediaRecorder.stop()停止捕获。

8,当你用完MediaRecorder实例之后,调用MediaRecorder.release()。调用MediaRecorder.release()一直是被推荐的立即释放资源的方法。

示例:音频录音和播放录音后的音频

下面示例类阐明了如何建立,开始和停止捕获音频,并且播放录音后的音频文件。

/*
 * The application needs to have the permission to write to external storage
 * if the output file is written to the external storage, and also the
 * permission to record audio. These permissions must be set in the
 * application's AndroidManifest.xml file, with something like:
 *
 * <uses-permission android:name="android.permission.WRITE_EXTERNAL_STORAGE" />
 * <uses-permission android:name="android.permission.RECORD_AUDIO" />
 *
 */
package com.android.audiorecordtest;

import android.app.Activity;
import android.widget.LinearLayout;
import android.os.Bundle;
import android.os.Environment;
import android.view.ViewGroup;
import android.widget.Button;
import android.view.View;
import android.view.View.OnClickListener;
import android.content.Context;
import android.util.Log;
import android.media.MediaRecorder;
import android.media.MediaPlayer;

import java.io.IOException;


public class AudioRecordTest extends Activity
{
    private static final String LOG_TAG = "AudioRecordTest";
    private static String mFileName = null;

    private RecordButton mRecordButton = null;
    private MediaRecorder mRecorder = null;

    private PlayButton   mPlayButton = null;
    private MediaPlayer   mPlayer = null;

    private void onRecord(boolean start) {
        if (start) {
            startRecording();
        } else {
            stopRecording();
        }
    }

    private void onPlay(boolean start) {
        if (start) {
            startPlaying();
        } else {
            stopPlaying();
        }
    }

    private void startPlaying() {
        mPlayer = new MediaPlayer();
        try {
            mPlayer.setDataSource(mFileName);
            mPlayer.prepare();
            mPlayer.start();
        } catch (IOException e) {
            Log.e(LOG_TAG, "prepare() failed");
        }
    }

    private void stopPlaying() {
        mPlayer.release();
        mPlayer = null;
    }

    private void startRecording() {
        mRecorder = new MediaRecorder();
        mRecorder.setAudioSource(MediaRecorder.AudioSource.MIC);
        mRecorder.setOutputFormat(MediaRecorder.OutputFormat.THREE_GPP);
        mRecorder.setOutputFile(mFileName);
        mRecorder.setAudioEncoder(MediaRecorder.AudioEncoder.AMR_NB);

        try {
            mRecorder.prepare();
        } catch (IOException e) {
            Log.e(LOG_TAG, "prepare() failed");
        }

        mRecorder.start();
    }

    private void stopRecording() {
        mRecorder.stop();
        mRecorder.release();
        mRecorder = null;
    }

    class RecordButton extends Button {
        boolean mStartRecording = true;

        OnClickListener clicker = new OnClickListener() {
            public void onClick(View v) {
                onRecord(mStartRecording);
                if (mStartRecording) {
                    setText("Stop recording");
                } else {
                    setText("Start recording");
                }
                mStartRecording = !mStartRecording;
            }
        };

        public RecordButton(Context ctx) {
            super(ctx);
            setText("Start recording");
            setOnClickListener(clicker);
        }
    }

    class PlayButton extends Button {
        boolean mStartPlaying = true;

        OnClickListener clicker = new OnClickListener() {
            public void onClick(View v) {
                onPlay(mStartPlaying);
                if (mStartPlaying) {
                    setText("Stop playing");
                } else {
                    setText("Start playing");
                }
                mStartPlaying = !mStartPlaying;
            }
        };

        public PlayButton(Context ctx) {
            super(ctx);
            setText("Start playing");
            setOnClickListener(clicker);
        }
    }

    public AudioRecordTest() {
        mFileName = Environment.getExternalStorageDirectory().getAbsolutePath();
        mFileName += "/audiorecordtest.3gp";
    }

    @Override
    public void onCreate(Bundle icicle) {
        super.onCreate(icicle);

        LinearLayout ll = new LinearLayout(this);
        mRecordButton = new RecordButton(this);
        ll.addView(mRecordButton,
            new LinearLayout.LayoutParams(
                ViewGroup.LayoutParams.WRAP_CONTENT,
                ViewGroup.LayoutParams.WRAP_CONTENT,
                0));
        mPlayButton = new PlayButton(this);
        ll.addView(mPlayButton,
            new LinearLayout.LayoutParams(
                ViewGroup.LayoutParams.WRAP_CONTENT,
                ViewGroup.LayoutParams.WRAP_CONTENT,
                0));
        setContentView(ll);
    }

    @Override
    public void onPause() {
        super.onPause();
        if (mRecorder != null) {
            mRecorder.release();
            mRecorder = null;
        }

        if (mPlayer != null) {
            mPlayer.release();
            mPlayer = null;
        }
    }
}

[root@RV1126 ~]# modetest -M rockchip -p CRTCs: id fb pos size 53 0 (0,0) (720x1280) 720x1280 62 720 800 830 910 1280 1292 1296 1308 74000 flags: nhsync, nvsync; type: preferred, driver props: 38 left margin: flags: range values: 0 100 value: 100 39 right margin: flags: range values: 0 100 value: 100 40 top margin: flags: range values: 0 100 value: 100 41 bottom margin: flags: range values: 0 100 value: 100 51 FEATURE: flags: immutable bitmask values: afbdc=0x1 value: 0 Planes: id crtc fb CRTC x,y x,y gamma size possible crtcs 52 0 0 0,0 0,0 0 0x00000001 formats: XR24 AR24 XB24 AB24 RG24 BG24 RG16 BG16 props: 8 type: flags: immutable enum enums: Overlay=0 Primary=1 Cursor=2 value: 1 50 FEATURE: flags: immutable bitmask values: scale=0x1 alpha=0x2 hdr2sdr=0x4 sdr2hdr=0x8 afbdc=0x10 value: 2 54 0 0 0,0 0,0 0 0x00000001 formats: XR24 AR24 XB24 AB24 RG24 BG24 RG16 BG16 NV12 NV16 NV24 props: 8 type: flags: immutable enum enums: Overlay=0 Primary=1 Cursor=2 value: 0 50 FEATURE: flags: immutable bitmask values: scale=0x1 alpha=0x2 hdr2sdr=0x4 sdr2hdr=0x8 afbdc=0x10 value: 3 [root@RV1126 ~]# modetest -M rockchip Encoders: id crtc type possible crtcs possible clones 55 53 DSI 0x00000001 0x00000000 Connectors: id encoder status name size (mm) modes encoders 56 55 connected DSI-1 68x121 1 55 modes: name refresh (Hz) hdisp hss hse htot vdisp vss vse vtot) 720x1280 62 720 800 830 910 1280 1292 1296 1308 74000 flags: nhsync, nvsync; type: preferred, driver props: 1 EDID: flags: immutable blob [root@RV1126 ~]# modetest -M rockchip -p CRTCs: id fb pos size 53 0 (0,0) (720x1280) 720x1280 62 720 800 830 910 1280 1292 1296 1308 74000 flags: nhsync, nvsync; type: preferred, driver props: 38 left margin: flags: range values: 0 100 value: 100 39 right margin: flags: range values: 0 100 value: 100 40 top margin: flags: range values: 0 100 value: 100 41 bottom margin: flags: range values: 0 100 value: 100 51 FEATURE: flags: immutable bitmask values: afbdc=0x1 value: 0 Planes: id crtc fb CRTC x,y x,y gamma size possible crtcs 52 0 0 0,0 0,0 0 0x00000001 formats: XR24 AR24 XB24 AB24 RG24 BG24 RG16 BG16 props: 8 type: flags: immutable enum enums: Overlay=0 Primary=1 Cursor=2 value: 1 50 FEATURE: flags: immutable bitmask values: scale=0x1 alpha=0x2 hdr2sdr=0x4 sdr2hdr=0x8 afbdc=0x10 value: 2 54 0 0 0,0 0,0 0 0x00000001 formats: XR24 AR24 XB24 AB24 RG24 BG24 RG16 BG16 NV12 NV16 NV24 props: 8 type: flags: immutable enum enums: Overlay=0 Primary=1 Cursor=2 value: 0 50 FEATURE: flags: immutable bitmask values: scale=0x1 alpha=0x2 hdr2sdr=0x4 sdr2hdr=0x8 afbdc=0x10 value: 3 [root@RV1126 ~]# ./lvgl_test 1 media get entity by name: stream_cif_dvp_id0 is null media get entity by name: stream_cif_dvp_id1 is null media get entity by name: stream_cif_dvp_id2 is null media get entity by name: stream_cif_dvp_id3 is null media get entity by name: rkcif-lvds-subdev is null media get entity by name: rkcif-lite-lvds-subdev is null media get entity by name: stream_cif is null media get entity by name: rkcif-dvp-sof is null media get entity by name: rkisp-mpfbc-subdev is null media get entity by name: rkisp_dmapath is null media get entity by name: rockchip-mipi-dphy-rx is null media get entity by name: rkcif_dvp is null media get entity by name: rkcif_dvp is null media get entity by name: rkcif_lite_mipi_lvds is null media get entity by name: rkisp-mpfbc-subdev is null media get entity by name: rkisp_dmapath is null media get entity by name: rkcif_dvp is null media get entity by name: rkcif_mipi_lvds is null media get entity by name: rkcif_dvp is null media get entity by name: rkcif_lite_mipi_lvds is null media get entity by name: rkcif_mipi_lvds is null [15:02:34.612142][CAMHW]:XCAM ERROR CamHwIsp20.cpp:1022: No free isp&ispp needed by fake camera! register factory : rkmpp register factory : rkmpp register factory : live555_rtsp_server register factory : video_enc register factory : audio_enc register factory : video_dec register factory : file_read_flow register factory : file_write_flow register factory : filter register factory : link_flow register factory : source_stream register factory : muxer_flow register factory : audio_dec register factory : output_stream register factory : move_detec register factory : occlusion_detec register factory : file_write_stream register factory : file_read_stream register factory : alsa_playback_stream register factory : alsa_capture_stream register factory : v4l2_capture_stream register factory : v4l2_output_stream register factory : drm_output_stream rga_api version 1.3.0_[11] (RGA is compiling with meson base: $PRODUCT_BASE) register factory : rkrga register factory : through_guard register factory : ANR register factory : AEC register factory : rockx_filter register factory : nn_result_input register factory : draw_filter register factory : rknn register factory : face_capture register factory : rockface_detect register factory : rockface_evaluate register factory : rockface_bodydetect register factory : rockface_recognize LVGL Test Application Starting... Found display: 1, 720x1280 =============================count_planes:1, Index: 0, ID: 54 Backlight enabled via /sys/class/backlight/backlight/brightness DRM display driver initialized successfully Touch device opened: /dev/input/event0 Touch input device registered successfully Keyboard device opened successfully Keyboard input device registered successfully Input driver initialized successfully Test mode: 1 Test setup completed, entering main loop... ^C Received signal 2, exiting... Application exiting... DRM display driver deinitialized Input driver deinitialized 为什么modetest -M rockchip -p看到有两个plan,id分别为52(primary)和54(overlay) 但代码里,打印的内容里只有=============================count_planes:1, Index: 0, ID: 54 static int get_drm_display_info(void) { drmModeRes *resources = drmModeGetResources(drm_fd); if (!resources) { printf("Failed to get DRM resources\n"); return -1; } // 查找第一个连接的显示器 for (int i = 0; i < resources->count_connectors; i++) { drmModeConnector *connector = drmModeGetConnector(drm_fd, resources->connectors[i]); if (connector && connector->connection == DRM_MODE_CONNECTED) { connector_id = connector->connector_id; if (connector->count_modes > 0) { mode = connector->modes[0]; actual_width = mode.hdisplay; actual_height = mode.vdisplay; printf("Found display: %d, %dx%d\n", connector->count_modes, actual_width, actual_height); } drmModeFreeConnector(connector); break; } if (connector) drmModeFreeConnector(connector); } // 查找第一个可用的CRTC if (resources->count_crtcs > 0) { crtc_id = resources->crtcs[0]; } // 查找Primary Plane drmModePlaneRes *plane_res = drmModeGetPlaneResources(drm_fd); for (int i = 0; i < plane_res->count_planes; i++) { drmModePlane *plane = drmModeGetPlane(drm_fd, plane_res->planes[i]); printf("=============================count_planes:%d, Index: %d, ID: %d\n", plane_res->count_planes, i, plane->plane_id); } drmModeFreeResources(resources); return 0; }
最新发布
07-11
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