AudioTrack获取进程修改指定app的StreamType
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2022-06-16 18:40:58
android车机设备为了特定的区别于手机终端设备的应用场景,需要将部分特殊的音频流在系统框架层强制进行转换,针对这一需求,所以我们可以在音频数据流生产之处,强制改变。首先看看系统定义多少种Audio StreamType上源码system/media/audio/include/system/audio-base.htypedef enum { AUDIO_STREAM_DEFAULT = -1, // (-1) AUDIO_STREAM_MIN = 0, AUDIO_STR...
android车机设备为了特定的区别于手机终端设备的应用场景,需要将部分特殊的音频流在系统框架层强制进行转换,针对这一需求,所以我们可以在音频数据流生产之处,强制改变。
首先看看系统定义多少种Audio StreamType
上源码system/media/audio/include/system/audio-base.h
typedef enum {
AUDIO_STREAM_DEFAULT = -1, // (-1)
AUDIO_STREAM_MIN = 0,
AUDIO_STREAM_VOICE_CALL = 0,
AUDIO_STREAM_SYSTEM = 1,
AUDIO_STREAM_RING = 2,
AUDIO_STREAM_MUSIC = 3,
AUDIO_STREAM_ALARM = 4,
AUDIO_STREAM_NOTIFICATION = 5,
AUDIO_STREAM_BLUETOOTH_SCO = 6,
AUDIO_STREAM_ENFORCED_AUDIBLE = 7,
AUDIO_STREAM_DTMF = 8,
AUDIO_STREAM_TTS = 9,
AUDIO_STREAM_ACCESSIBILITY = 10,
AUDIO_STREAM_REROUTING = 11,
AUDIO_STREAM_PATCH = 12,
AUDIO_STREAM_PUBLIC_CNT = 11, // (ACCESSIBILITY + 1)
AUDIO_STREAM_FOR_POLICY_CNT = 12, // PATCH
AUDIO_STREAM_CNT = 13, // (PATCH + 1)
} audio_stream_type_t;
下面以导航app为例,导航在车机的应用场景的数据流级别高于普通的媒体播放,所以我们把导航app默认设置的music type强制修改为alarm流,这样以备后续的车机音频策略的实施。
音频数据的生产者AudioTrack可以助我们一臂之力,简单的描述下思路便直接上代码,直接获取到对应导航app的进程,当前进程活跃(导航在进行tts语音播报的时刻),强制修改为AUDIO_STREAM_ALARM .
frameworks\av\media\libaudioclient\AudioTrack.cpp
增加函数获取
static int get_pack_from_cmdline(int pid, char *buf, int len) {
char filename[256];
int n = 0;
int fd;
if (pid < 1 || buf == NULL || len < 256) {
return -1;
}
memset(filename, 0, 256);
sprintf(filename, "/proc/%d/cmdline", pid);
fd = open(filename, O_RDONLY);
if (fd < 0) {
perror("open:");
return -1;
}
int ret = read(fd, buf, len);
close(fd);
memset(filename, 0, 256);
while (1) {
if (buf[n] == ' '||buf[n] == ':')
break;
filename[n] = buf[n];
n++;
if (n == ret)
break;
}
memset(buf, 0, len);
memcpy(buf, filename, n + 1);
return ret;
}
AudioTrack最初设置playback参数的set函数具体实施流类型的转变
status_t AudioTrack::set(
audio_stream_type_t streamType,
uint32_t sampleRate,
audio_format_t format,
audio_channel_mask_t channelMask,
size_t frameCount,
audio_output_flags_t flags,
callback_t cbf,
void* user,
int32_t notificationFrames,
const sp<IMemory>& sharedBuffer,
bool threadCanCallJava,
audio_session_t sessionId,
transfer_type transferType,
const audio_offload_info_t *offloadInfo,
uid_t uid,
pid_t pid,
const audio_attributes_t* pAttributes,
bool doNotReconnect,
float maxRequiredSpeed)
{
MTK_ALOGI("set(): %p, streamType %d, sampleRate %u, format %#x, channelMask %#x, frameCount %zu, "
"flags #%x, notificationFrames %d, sessionId %d, transferType %d, uid %d, pid %d",
this, streamType, sampleRate, format, channelMask, frameCount, flags,
notificationFrames, sessionId, transferType, uid, pid);
ALOGV("set(): streamType %d, sampleRate %u, format %#x, channelMask %#x, frameCount %zu, "
"flags #%x, notificationFrames %d, sessionId %d, transferType %d, uid %d, pid %d",
streamType, sampleRate, format, channelMask, frameCount, flags, notificationFrames,
sessionId, transferType, uid, pid);
...
...
//获取进程
char pidName[256];
memset(pidName, 0, 256);
get_pack_from_cmdline(getpid(), pidName, 256);
if (strcmp(pidName,"具体的导航app进程名,eg.高德com.autonavi.amapauto")== 0){
mSteamType = AUDIO_STREAM_ALARM ;
}
如此一来,就可以将导航的audio数据流和媒体播放的数据流区别,以便车机上的音频策略的实现.
本文地址:https://blog.csdn.net/jeephao/article/details/107302285