【stagefrightplayer】4 OMX Codec介绍 （2/2）

4.1 看下 drainInputBuffers();实现

<PRE class=html name="code">void OMXCodec::drainInputBuffers() {
for (size_t i = 0; i < buffers->size(); ++i) {
BufferInfo *info = &buffers->editItemAt(i);
if (info->mStatus != OWNED_BY_US) {
continue;
}
if (!drainInputBuffer(info)) {
break;
}
if (mFlags & kOnlySubmitOneInputBufferAtOneTime) {
break;
}
}
}</PRE>

bool OMXCodec::drainInputBuffer(BufferInfo *info) {
**********
status_t err;
bool signalEOS = false;
int64_t timestampUs = 0;
size_t offset = 0;
int32_t n =  0;
for (;;) {
MediaBuffer *srcBuffer;
err = mSource->read(&srcBuffer);
size_t remainingBytes = info->mSize - offset;
下面是判断从extractor读取到的数据是不是超过了总大小
if (srcBuffer->range_length() > remainingBytes) {
if (offset == 0) {
srcBuffer->release();
srcBuffer = NULL;

setState(ERROR);
return false;
}
mLeftOverBuffer = srcBuffer;
break;
} memcpy((uint8_t *)info->mData + offset,
(const uint8_t *)srcBuffer->data()
+ srcBuffer->range_offset(),
srcBuffer->range_length());
offset += srcBuffer->range_length();
if (releaseBuffer) {
srcBuffer->release();
srcBuffer = NULL;
}
数据读取完毕后将srcBufferrelease掉
}
err = mOMX->emptyBuffer(
mNode, info->mBuffer, 0, offset,
flags, timestampUs);
info->mStatus = OWNED_BY_COMPONENT;
}