【R128】基础组件开发指南——RTOS 多媒体编码
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RTOS 多媒体编码
介绍 FreeRTOS 下如何使用 xrecorder 的接口来开发录制应用程序,方便录制应用开发人员快速正确地开发,以及录制应用测试人员如何根据该文档对基于 xrecord 的录制应用进行验证测试。
编码支持情况
目前 RTOS 平台多媒体编码应用支持的编码格式分别为:pcm、amr、mp3、speex、opus。
其中 pcm、amr、mp3 可通过 xrecorder 进行编码以及录制;speex 和 opus 可通过第三方示例工程进行编码。
xrecorder 状态图
这张状态转换图清晰地描述了 xrecorder 的各个状态,也列举了主要的方法的调用时序,每种方法只能在一些特定的状态下使用,否则会出错。
Init 状态
Idle 状态:当调用 XRecordCreate() 创建一个 xrecord 时,处于 idle 状态。
Prepared 状态
调用 XRecordPrepare() 函数并返回后,xrecorder 处于 Prepared 状态。在这个状态下说明所有的资源都已经就绪了,调用 XRecordStart() 函数就可以进行录制。
Started 状态
xrecorder prepare 完成后,调用 XRecordStart() 进行录制,当应用开始录制后,xrecorder 就处于 Started 状态,这表明 xrecorder 正在录制文件。
Stopped 状态
Started 状态下均可调用 XrecordStop() 停止 xrecorder,而处于 Stop 状态的 xrecorder 要想重新录制,需要通过 XRecorderPrepare() 回到先前的 Prepared 状态重新开始才可以。
Destroyed 状态
通过 XRecordDestroy() 的方法可以进入 Destroyed 状态,只要 xrecorder 不再被使用,就应当尽快将其 destroy 掉。
接口函数
创建一个 XRecord
XRecord *XRecordCreate()
参数:
- 无
返回值:
- 无
设置录制音频的编码格式
int XRecordSetAudioEncodeType(XRecord *p, XRECODER_AUDIO_ENCODE_TYPE type, XRecordConfig *config)
参数:
- p: 通过 XRecordCreate 创建的 XRecord 指针
- type: 已支持的编码格式
- config: 上层应用对音频属性的配置
返回值:
- 成功: 0; 失败: ‑1
获取指针
获取指向音频设备管理模块的指针,用于录制音频
void XRecordSetAudioCap(XRecord* p, const CaptureCtrl* audioSrc)
参数:
- p: 通过 XRecordCreate 创建的 XRecord 指针
- audioSrc: 由上层应用获取的音频设备管理模块的指针
返回值:
- 无
audioSrc 可在上层应用通过调用 cedarx 的音频设备管理模块的 RTCaptureDeviceCreate 来创建。
设置录制后文件的保存的路径
int XRecordSetDataDstUrl(XRecord* p, const char* pUrl, void* arg, const CdxKeyedVectorT* pHeaders)
参数:
- p: 通过 XRecordCreate 创建的 XRecord 指针
- pUrl:url 地址
返回值:
- 成功:0;失败:‑1
将 XRecord 置为准备状态, 准备 Muxer
int XRecordPrepare(XRecord* p)
参数:
- p:通过 XRecordCreate 创建的 XRecord 指针
返回值:
- 成功:0;失败:‑1
将 XRecord 置为启动状态
int XRecordStart(XRecord* p)
参数:
- p:通过 XRecordCreate 创建的 XRecord 指针
返回值:
- 成功:0;失败:‑1
将 XRecord 置为停止状态
int XRecordStop(XRecord* p)
参数:
- p:通过 XRecordCreate 创建的 XRecord 指针
返回值:
- 成功: 0;失败:‑1
编码数据入队封装
提供接口给下层编码模块,将编码数据放进缓存队列中等待封装
int onAudioDataEnc(XRecord* app, CdxMuxerPacketT* buff)
参数:
- app: xrecorder 的环境句柄;
- buff:编码后的缓存数据
返回值:
- 成功: 0;失败:‑1
销毁一个 XRecord
int XRecordDestroy(XRecord* p)
参数:
- p:通过 XRecordCreate 创建的 XRecord 指针
返回值:
- 成功: 0;失败:‑1
XRecorder 开发流程
XRecordCreate()
//创建一个录制应用XRecordSetAudioCap()
//设置音频采集设备;可先调用RTCaptureDeviceCreate
创建。XRecordSetDataDstUrl()
//设置录制后文件保存位置XRecordSetAudioEncodeType()
//设置音频数据的编码格式XRecordPrepare()
//设置 Muxer,让 xrecorder 进入准备状态XRecordStart()
//开始录制XRecordStop()
//停止录制XRecordDestroy()
//当不需要进行录制的时候,销毁 xrecorder
注意事项
- 在调用 XRecordSetAudioCap 设置音频采集设备之前,需先打开音频采集设备来获取句柄。在 rtos 平台可调用 libcedarx 提供的音频采集设备控制模块 rtosCaptureControl.c 中的
RTCaptureDeviceCreate
来创建句柄。 - recorder 应用未支持暂停录制。
- recorder 的录制时长为调用 XRecordStart 至调用 XRecordStop 之间的时长来决定,因此上层应用需要录制指定时长的音频时,录制的步骤应为调用 XRecordStart,等待指定的时间,调用XRecordStop。
示例代码
#include <stdio.h> #include <stdlib.h> #include <stdbool.h> #include <string.h> #include <aw_common.h> #include <console.h> #include "vfs.h" #include "xrecord.h" #define RECORDER_LOGD(msg, arg...) printf("[RECORDER_DBG] <%s : %d> " msg "\n", __func__, __LINE__, ##arg) #define RECORDER_LOGI(msg, arg...) printf("[RECORDER_INFO] <%s : %d> " msg "\n", __func__, __LINE__, ##arg) #define RECORDER_LOGW(msg, arg...) printf("[RECORDER_WRN] <%s : %d> " msg "\n", __func__, __LINE__, ##arg) #define RECORDER_LOGE(msg, arg...) printf("[RECORDER_ERR] <%s : %d> " msg "\n", __func__, __LINE__, ##arg) typedef struct recorder_base recorder_base; typedef struct rec_cfg { XRECODER_AUDIO_ENCODE_TYPE type; int sample_rate; int chan_num; int bitrate; int sampler_bits; } rec_cfg; struct recorder_base { int (*start)(recorder_base *base, const char *url, const rec_cfg *cfg); int (*stop)(recorder_base *base); }; struct ExampleCustomerWriterImpl { CdxWriterT base; vfs_file_t *vfs; }; typedef struct recorder { recorder_base base; XRecord *xrecorder; CaptureCtrl *cap; } recorder; recorder_base *recorder_create(); int recorder_destroy(recorder_base *base); /* Example Customer Writer */ static int __CdxExampleConnect(CdxWriterT *writer) { struct ExampleCustomerWriterImpl *impl; impl = (struct ExampleCustomerWriterImpl *)writer; vfs_unlink("data/record/2.amr"); impl->vfs = vfs_open("data/record/2.amr", VFS_RDWR | VFS_CREAT); if (impl->vfs == NULL) { return -1; } return 0; } static int __CdxExampleRead(CdxWriterT *writer, void *buf, int size) { return 0; } static int __CdxExampleWrite(CdxWriterT *writer, void *buf, int size) { uint32_t write_len; struct ExampleCustomerWriterImpl *impl; impl = (struct ExampleCustomerWriterImpl *)writer; write_len = vfs_write(impl->vfs, buf, size); return write_len; } static long __CdxExampleSeek(CdxWriterT *writer, long moffset, int mwhere) { return 0; } static long __CdxExampleTell(CdxWriterT *writer) { return 0; } static int __CdxExampleClose(CdxWriterT *writer) { struct ExampleCustomerWriterImpl *impl; impl = (struct ExampleCustomerWriterImpl *)writer; vfs_close(impl->vfs); free(impl); return 0; } static const struct CdxWriterOps exampleCustomerWriteOps = { .cdxConnect = __CdxExampleConnect, .cdxRead = __CdxExampleRead, .cdxWrite = __CdxExampleWrite, .cdxSeek = __CdxExampleSeek, .cdxTell = __CdxExampleTell, .cdxClose = __CdxExampleClose }; CdxWriterT *ExampleCustomerWriterCreat() { struct ExampleCustomerWriterImpl *impl; impl = malloc(sizeof(*impl)); if (impl == NULL) { printf("example customer writer create fail.\n"); return NULL; } memset(impl, 0, sizeof(*impl)); impl->base.ops = &exampleCustomerWriteOps; return &impl->base; } /* Main App */ static void showHelp(){ printf("\n"); printf("**************************\n"); printf("* This is a simple audio recoder, when it is started, you can input commands to tell\n"); printf("* what you want it to do.\n"); printf("* Usage: \n"); printf("* cedarx_record amr 10 : this means record 10s amr music\n"); printf("* cedarx_record pcm 10 : this means record 10s pcm music\n"); printf("**************************\n"); } recorder *recorder_singleton = NULL; static int record_start(recorder_base *base, const char *url, const rec_cfg *cfg) { recorder *impl = container_of(base, recorder, base); XRecordConfig audioConfig; if (cfg->type == XRECODER_AUDIO_ENCODE_PCM_TYPE) { audioConfig.nChan = cfg->chan_num; audioConfig.nSamplerate = cfg->sample_rate; audioConfig.nSamplerBits = cfg->sampler_bits; audioConfig.nBitrate = cfg->bitrate; } else if (cfg->type == XRECODER_AUDIO_ENCODE_AMR_TYPE) { audioConfig.nChan = 1; audioConfig.nSamplerate = 8000;//amr-nb 8000Hz amr-wb 16000Hz audioConfig.nSamplerBits = 16; audioConfig.nBitrate = 12200;//amr-nb 12200 amr-wb 23850 } else { audioConfig.nChan = cfg->chan_num; audioConfig.nSamplerate = cfg->sample_rate; audioConfig.nSamplerBits = cfg->sampler_bits; audioConfig.nBitrate = cfg->bitrate; } XRecordSetDataDstUrl(impl->xrecorder, url, NULL, NULL); XRecordSetAudioEncodeType(impl->xrecorder, cfg->type, &audioConfig); XRecordPrepare(impl->xrecorder); XRecordStart(impl->xrecorder); RECORDER_LOGI("record start"); return 0; } static int record_stop(recorder_base *base) { recorder *impl = container_of(base, recorder, base); XRecordStop(impl->xrecorder); return 0; } extern CaptureCtrl* RTCaptureDeviceCreate(); recorder_base *recorder_create() { if (recorder_singleton != NULL) return &recorder_singleton->base; recorder *impl = malloc(sizeof(*impl)); if (impl == NULL) return NULL; memset(impl, 0, sizeof(*impl)); impl->xrecorder = XRecordCreate(); if (impl->xrecorder == NULL) goto failed; impl->cap = (void *)(uintptr_t)RTCaptureDeviceCreate(); if (impl->cap == NULL) goto failed; XRecordSetAudioCap(impl->xrecorder, impl->cap); impl->base.start = record_start; impl->base.stop = record_stop; recorder_singleton = impl; return &impl->base; failed: RECORDER_LOGE("recorder create failed"); if (impl->xrecorder) XRecordDestroy(impl->xrecorder); if (impl) free(impl); return NULL; } int recorder_destroy(recorder_base *base) { recorder *impl = container_of(base, recorder, base); if (impl->xrecorder) { XRecordDestroy(impl->xrecorder); } free(impl); recorder_singleton = NULL; return 0; } static int cedarx_record_test(int argc, char **argv) { recorder_base *recorder; rec_cfg cfg; char music_url[64]; char file_url[64]; CdxWriterT *writer; memset(file_url, 0, 64); if(argc == 3){ if( !strncmp("amr", argv[1], sizeof("amr")-1) ){ cfg.type = XRECODER_AUDIO_ENCODE_AMR_TYPE; snprintf(file_url, 64, "file://data/%ds.amr", atoi(argv[2])); cfg.sample_rate = 8000;//8000 cfg.chan_num = 1;//1 cfg.bitrate = 12200; cfg.sampler_bits = 16; } else if( !strncmp("pcm", argv[1], sizeof("pcm")-1) ){ cfg.type = XRECODER_AUDIO_ENCODE_PCM_TYPE; snprintf(file_url, 64, "file://data/%ds.pcm", atoi(argv[2])); cfg.sample_rate = 8000;//8000 cfg.chan_num = 1;//1 cfg.bitrate = 12200; cfg.sampler_bits = 16; } else if( !strncmp("mp3", argv[1], sizeof("mp3")-1) ){ cfg.type = XRECODER_AUDIO_ENCODE_MP3_TYPE; snprintf(file_url, 64, "file://data/%ds.mp3", atoi(argv[2])); cfg.sample_rate = 16000; cfg.chan_num = 1; cfg.bitrate = 32000; cfg.sampler_bits = 16; } else { printf("now support!\n"); return -1; } }else{ printf("the parameter is error,usage is as following:\n"); showHelp(); return -1; } recorder = recorder_create(); if (recorder == NULL) { printf("recorder create fail, exit\n"); return -1; } printf("===start record %s now, last for %d s===\n", argv[1], atoi(argv[2])); recorder->start(recorder, file_url, &cfg); sleep(atoi(argv[2])); recorder->stop(recorder); printf("record %s over.\n", argv[1]); exit: return recorder_destroy(recorder); } FINSH_FUNCTION_EXPORT_CMD(cedarx_record_test, cedarx_record, cedarx record test demo);
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