From 373eada6ff187bf59e33c2d3b8e33c2ca1581f30 Mon Sep 17 00:00:00 2001 From: Lawrence Rust Date: Fri, 3 Jun 2011 15:08:57 +0200 Subject: [PATCH 42/42] RingBuffer: CalcReadAheadThresh mods for low bit rate (radio) streams The existing readahead block size is too large for 64/128 kBps audio streams and can cause audio underruns. Make WaitFailAvail return the bytes available if less than that requested for low bit rate streams (where fill_min is < 32kB). Signed-off-by: Lawrence Rust --- mythtv/libs/libmythtv/RingBuffer.cpp | 54 ++++++++++++++++++++++----------- 1 files changed, 36 insertions(+), 18 deletions(-) diff --git a/mythtv/libs/libmythtv/RingBuffer.cpp b/mythtv/libs/libmythtv/RingBuffer.cpp index 95fb96b..eda425a 100644 --- a/mythtv/libs/libmythtv/RingBuffer.cpp +++ b/mythtv/libs/libmythtv/RingBuffer.cpp @@ -540,7 +540,7 @@ void RingBuffer::OpenFile(const QString &lfilename, uint retry_ms) commserror = false; numfailures = 0; - rawbitrate = 8000; + rawbitrate = 2500; CalcReadAheadThresh(); rwlock.unlock(); @@ -806,33 +806,48 @@ void RingBuffer::CalcReadAheadThresh(void) // loop without sleeping if the buffered data is less than this fill_threshold = kBufferSize / 8; - const uint KB32 = 32*1024; - const uint KB64 = 64*1024; - const uint KB128 = 128*1024; - const uint KB256 = 256*1024; - const uint KB512 = 512*1024; + const int KB1 = 1024; + const int KB2 = 2*1024; + const int KB4 = 4*1024; + const int KB8 = 8*1024; + const int KB16 = 16*1024; + const int KB32 = 32*KB1; + const int KB64 = 64*KB1; + const int KB128 = 128*KB1; + const int KB256 = 256*KB1; + const int KB512 = 512*KB1; estbitrate = (uint) max(abs(rawbitrate * playspeed), 0.5f * rawbitrate); estbitrate = min(rawbitrate * 3, estbitrate); - int rbs = (estbitrate > 2500) ? KB64 : KB32; - rbs = (estbitrate > 5000) ? KB128 : rbs; - rbs = (estbitrate > 9000) ? KB256 : rbs; - rbs = (estbitrate > 18000) ? KB512 : rbs; - readblocksize = max(rbs,readblocksize); + + int const rbs = estbitrate > 18000 ? KB512 : + estbitrate > 9000 ? KB256 : + estbitrate > 5000 ? KB128 : + estbitrate > 2500 ? KB64 : + estbitrate > 1000 ? KB32 : + estbitrate > 500 ? KB16 : + estbitrate > 250 ? KB8 : + estbitrate > 125 ? KB4 : + KB2; + if (rbs < CHUNK) + readblocksize = rbs; + else + readblocksize = max(rbs,readblocksize); // minumum seconds of buffering before allowing read - float secs_min = 0.25; + float const secs_min = 0.25f; // set the minimum buffering before allowing ffmpeg read - fill_min = (uint) ((estbitrate * secs_min) * 0.125f); + fill_min = (uint) (estbitrate * ((KB1 / 8) * secs_min)); // make this a multiple of ffmpeg block size.. - fill_min = ((fill_min / KB32) + 1) * KB32; + if (fill_min > CHUNK) + fill_min = (fill_min / CHUNK) * CHUNK; VERBOSE(VB_FILE, LOC + QString("CalcReadAheadThresh(%1 Kb)\n\t\t\t -> " "threshhold(%2 KB) min read(%3 KB) blk size(%4 KB)") - .arg(estbitrate).arg(fill_threshold/1024) - .arg(fill_min/1024).arg(readblocksize/1024)); + .arg(estbitrate).arg(fill_threshold/KB1) + .arg(fill_min/KB1).arg(readblocksize/KB1)); } bool RingBuffer::IsNearEnd(double fps, uint vvf) const @@ -1182,7 +1197,7 @@ void RingBuffer::run(void) (now.tv_usec - lastread.tv_usec) / 1000; readtimeavg = (readtimeavg * 9 + readinterval) / 10; - if (readtimeavg < 150 && (uint)readblocksize < (kBufferSize>>2)) + if (readtimeavg < 150 && (uint)readblocksize < (kBufferSize>>2) && readblocksize >= CHUNK) { int old_block_size = readblocksize; readblocksize = 3 * readblocksize / 2; @@ -1431,7 +1446,10 @@ bool RingBuffer::WaitForAvail(int count) if (avail < count) { int elapsed = t.elapsed(); - if (((elapsed > 250) && (elapsed < 500)) || + // Return avail for low bitrate audio streams to avoid underrun + if (elapsed >= 500 && fill_min < CHUNK && avail >= fill_min) + count = avail; + else if (((elapsed > 250) && (elapsed < 500)) || ((elapsed > 500) && (elapsed < 750)) || ((elapsed > 1000) && (elapsed < 1250)) || ((elapsed > 2000) && (elapsed < 2250)) || -- 1.7.4.1