stagefright: httplive: Reduce memcpy calls for chunked content
Streams using http chunking will not report the segment's total
content-length. In this case, a 64k buffer is allocated and is
increased by 32k each time the buffer is filled again. For high
bitrate content, this can lead to a large number of copies that
affect the HLS framework delay. Increase fetchFile buffer size
exponentially by 50% or at least 32k instead of by 32k each time
to reduce the number of memcpy calls.
Example for a chunked 6 MB 1080p segment (ie ~3s):
Adding 32k:
190 copies with 572.97 MB copied
Increasing by 50%:
12 copies with 16.09 MB copied
Bug: 18821145
Change-Id: Iedf0e4437e96026a58d50bce2660f85ac90d0ada
diff --git a/media/libstagefright/httplive/LiveSession.cpp b/media/libstagefright/httplive/LiveSession.cpp
index cad4c2d..e163985 100644
--- a/media/libstagefright/httplive/LiveSession.cpp
+++ b/media/libstagefright/httplive/LiveSession.cpp
@@ -873,7 +873,11 @@
// Only resize when we don't know the size.
size_t bufferRemaining = buffer->capacity() - buffer->size();
if (bufferRemaining == 0 && getSizeErr != OK) {
- bufferRemaining = 32768;
+ size_t bufferIncrement = buffer->size() / 2;
+ if (bufferIncrement < 32768) {
+ bufferIncrement = 32768;
+ }
+ bufferRemaining = bufferIncrement;
ALOGV("increasing download buffer to %zu bytes",
buffer->size() + bufferRemaining);