WEBRTC源码片段分析(1)音频缓冲拷贝
2015-07-08 13:45
441 查看
源码位置
webrtc/webrtc/modules/audio_device/ios/audio_device_ios.cc
函数
OSStatus
AudioDeviceIPhone::RecordProcessImpl(
AudioUnitRenderActionFlags *ioActionFlags,
const AudioTimeStamp *inTimeStamp,
uint32_t inBusNumber,
uint32_t inNumberFrames)
{
...........
while (bufPos < N_REC_BUFFERS)
{
if ((_recordingLength[bufPos] > 0) && (_recordingLength[bufPos] < noSamp10ms))
{
// Found the partially full buffer
insertPos = static_cast<int16_t>(bufPos);
// Don't need to search more, quit loop
bufPos = N_REC_BUFFERS;
}
else if ((-1 == insertPos) && (0 == _recordingLength[bufPos]))
{
// Found an empty buffer
insertPos = static_cast<int16_t>(bufPos);
}
++bufPos;
}
...............
}
一开始阅读这段函数时,简单理解就是查找未使用,或者未完全填满的槽位,理解是理解了但感觉有点效率不高,故优化了下,结果理解就出了问题.
OSStatus
AudioDeviceIPhone::RecordProcessImpl(
AudioUnitRenderActionFlags *ioActionFlags,
const AudioTimeStamp *inTimeStamp,
uint32_t inBusNumber,
uint32_t inNumberFrames)
{
...........
bufPos = 0;
insertPos = -1;
nCopy = 0;
//查找未使用,或者未完全填满的槽位
while (bufPos < N_REC_BUFFERS)
{
if ((_recordingLength[bufPos] > 0) && (_recordingLength[bufPos] < noSamp10ms))
{
// Found the partially full buffer
insertPos = static_cast<int16_t>(bufPos);
// Don't need to search more, quit loop
break;
}
else if ((-1 == insertPos) && (0 == _recordingLength[bufPos]))
{
insertPos = static_cast<int16_t>(bufPos);
break;
}
++bufPos;
}
...............
}
相比原版,增加了两个break,结果仔细思考发现,第二个break是不对的.找到空槽位之后,仍然要考虑遍历下有没有未填满的槽位.
OSStatus
AudioDeviceIPhone::RecordProcessImpl(
AudioUnitRenderActionFlags *ioActionFlags,
const AudioTimeStamp *inTimeStamp,
uint32_t inBusNumber,
uint32_t inNumberFrames)
{
...........
bufPos = 0;
insertPos = -1;
nCopy = 0;
//查找未使用,或者未完全填满的槽位
while (bufPos < N_REC_BUFFERS)
{
if ((_recordingLength[bufPos] > 0) && (_recordingLength[bufPos] < noSamp10ms))
{
// Found the partially full buffer
insertPos = static_cast<int16_t>(bufPos);
// Don't need to search more, quit loop
break;
}
else if ((-1 == insertPos) && (0 == _recordingLength[bufPos]))
{
// Found an empty buffer,找到空槽后,再继续找长度不足的槽位,优先使用
insertPos = static_cast<int16_t>(bufPos);
}
++bufPos;
}
...............
}
修正后OK了,这还是要仔细阅读,理解清楚了需求.如果使用链表,就不会有问题了.
webrtc/webrtc/modules/audio_device/ios/audio_device_ios.cc
函数
OSStatus
AudioDeviceIPhone::RecordProcessImpl(
AudioUnitRenderActionFlags *ioActionFlags,
const AudioTimeStamp *inTimeStamp,
uint32_t inBusNumber,
uint32_t inNumberFrames)
{
...........
while (bufPos < N_REC_BUFFERS)
{
if ((_recordingLength[bufPos] > 0) && (_recordingLength[bufPos] < noSamp10ms))
{
// Found the partially full buffer
insertPos = static_cast<int16_t>(bufPos);
// Don't need to search more, quit loop
bufPos = N_REC_BUFFERS;
}
else if ((-1 == insertPos) && (0 == _recordingLength[bufPos]))
{
// Found an empty buffer
insertPos = static_cast<int16_t>(bufPos);
}
++bufPos;
}
...............
}
一开始阅读这段函数时,简单理解就是查找未使用,或者未完全填满的槽位,理解是理解了但感觉有点效率不高,故优化了下,结果理解就出了问题.
OSStatus
AudioDeviceIPhone::RecordProcessImpl(
AudioUnitRenderActionFlags *ioActionFlags,
const AudioTimeStamp *inTimeStamp,
uint32_t inBusNumber,
uint32_t inNumberFrames)
{
...........
bufPos = 0;
insertPos = -1;
nCopy = 0;
//查找未使用,或者未完全填满的槽位
while (bufPos < N_REC_BUFFERS)
{
if ((_recordingLength[bufPos] > 0) && (_recordingLength[bufPos] < noSamp10ms))
{
// Found the partially full buffer
insertPos = static_cast<int16_t>(bufPos);
// Don't need to search more, quit loop
break;
}
else if ((-1 == insertPos) && (0 == _recordingLength[bufPos]))
{
insertPos = static_cast<int16_t>(bufPos);
break;
}
++bufPos;
}
...............
}
相比原版,增加了两个break,结果仔细思考发现,第二个break是不对的.找到空槽位之后,仍然要考虑遍历下有没有未填满的槽位.
OSStatus
AudioDeviceIPhone::RecordProcessImpl(
AudioUnitRenderActionFlags *ioActionFlags,
const AudioTimeStamp *inTimeStamp,
uint32_t inBusNumber,
uint32_t inNumberFrames)
{
...........
bufPos = 0;
insertPos = -1;
nCopy = 0;
//查找未使用,或者未完全填满的槽位
while (bufPos < N_REC_BUFFERS)
{
if ((_recordingLength[bufPos] > 0) && (_recordingLength[bufPos] < noSamp10ms))
{
// Found the partially full buffer
insertPos = static_cast<int16_t>(bufPos);
// Don't need to search more, quit loop
break;
}
else if ((-1 == insertPos) && (0 == _recordingLength[bufPos]))
{
// Found an empty buffer,找到空槽后,再继续找长度不足的槽位,优先使用
insertPos = static_cast<int16_t>(bufPos);
}
++bufPos;
}
...............
}
修正后OK了,这还是要仔细阅读,理解清楚了需求.如果使用链表,就不会有问题了.
相关文章推荐
- SQL 判断列是否存在
- 黑马程序员——程序设计模式
- osgEarth学习笔记
- C#.net中,点击asp控件button复制内容到剪贴板
- Tor浏览器:Linux下用于匿名Web浏览的终极浏览器
- [Win32SDK基本]开启UI系统风格
- Math summation symbol in LaTeX
- 最后通牒
- 关于百度echarts使用
- 从客户端(textarea="<p>wewqe</p>")中检测到有潜在危险的 Request.QueryString 值。
- Linux 下如何处理包含空格和特殊字符的文件名
- [leetcode] 233.Number of Digit One
- MySQL读取中文乱码的问题。
- 《猜猜看》游戏开发
- APUE(第十章)信号
- 算法基础:最大递减数问题(Golang实现)
- Android 曾经的小Bug(常识)
- express安装
- 华为H3C的VLAN比思科的VLAN真心复杂
- 集群基础和分类