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/* Copyright (C) 2000-2003 Constantin Kaplinsky. All Rights Reserved.
* Copyright (C) 2011 D. R. Commander. All Rights Reserved.
* Copyright 2014 Pierre Ossman for Cendio AB
*
* This is free software; you can redistribute it and/or modify
* it under the terms of the GNU General Public License as published by
* the Free Software Foundation; either version 2 of the License, or
* (at your option) any later version.
*
* This software is distributed in the hope that it will be useful,
* but WITHOUT ANY WARRANTY; without even the implied warranty of
* MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
* GNU General Public License for more details.
*
* You should have received a copy of the GNU General Public License
* along with this software; if not, write to the Free Software
* Foundation, Inc., 59 Temple Place - Suite 330, Boston, MA 02111-1307,
* USA.
*/
#include <rdr/OutStream.h>
#include <rfb/encodings.h>
#include <rfb/SConnection.h>
#include <rfb/PixelBuffer.h>
#include <rfb/TightJPEGEncoder.h>
#include <rfb/TightConstants.h>
using namespace rfb;
struct TightJPEGConfiguration {
int quality;
int subsampling;
};
// NOTE: The JPEG quality and subsampling levels below were obtained
// experimentally by the VirtualGL Project. They represent the approximate
// average compression ratios listed below, as measured across the set of
// every 10th frame in the SPECviewperf 9 benchmark suite.
//
// 9 = JPEG quality 100, no subsampling (ratio ~= 10:1)
// [this should be lossless, except for round-off error]
// 8 = JPEG quality 92, no subsampling (ratio ~= 20:1)
// [this should be perceptually lossless, based on current research]
// 7 = JPEG quality 86, no subsampling (ratio ~= 25:1)
// 6 = JPEG quality 79, no subsampling (ratio ~= 30:1)
// 5 = JPEG quality 77, 4:2:2 subsampling (ratio ~= 40:1)
// 4 = JPEG quality 62, 4:2:2 subsampling (ratio ~= 50:1)
// 3 = JPEG quality 42, 4:2:2 subsampling (ratio ~= 60:1)
// 2 = JPEG quality 41, 4:2:0 subsampling (ratio ~= 70:1)
// 1 = JPEG quality 29, 4:2:0 subsampling (ratio ~= 80:1)
// 0 = JPEG quality 15, 4:2:0 subsampling (ratio ~= 100:1)
static const struct TightJPEGConfiguration conf[10] = {
{ 15, subsample4X }, // 0
{ 29, subsample4X }, // 1
{ 41, subsample4X }, // 2
{ 42, subsample2X }, // 3
{ 62, subsample2X }, // 4
{ 77, subsample2X }, // 5
{ 79, subsampleNone }, // 6
{ 86, subsampleNone }, // 7
{ 92, subsampleNone }, // 8
{ 100, subsampleNone } // 9
};
TightJPEGEncoder::TightJPEGEncoder(SConnection* conn) :
Encoder(conn, encodingTight,
(EncoderFlags)(EncoderUseNativePF | EncoderLossy), -1, 9),
qualityLevel(-1), fineQuality(-1), fineSubsampling(subsampleUndefined)
{
}
TightJPEGEncoder::~TightJPEGEncoder()
{
}
bool TightJPEGEncoder::isSupported()
{
if (!conn->client.supportsEncoding(encodingTight))
return false;
// Any one of these indicates support for JPEG
if (conn->client.qualityLevel != -1)
return true;
if (conn->client.fineQualityLevel != -1)
return true;
if (conn->client.subsampling != -1)
return true;
// Tight support, but not JPEG
return false;
}
void TightJPEGEncoder::setQualityLevel(int level)
{
qualityLevel = level;
}
void TightJPEGEncoder::setFineQualityLevel(int quality, int subsampling)
{
fineQuality = quality;
fineSubsampling = subsampling;
}
int TightJPEGEncoder::getQualityLevel()
{
return qualityLevel;
}
void TightJPEGEncoder::writeRect(const PixelBuffer* pb, const Palette& palette)
{
const rdr::U8* buffer;
int stride;
int quality, subsampling;
rdr::OutStream* os;
buffer = pb->getBuffer(pb->getRect(), &stride);
if (qualityLevel >= 0 && qualityLevel <= 9) {
quality = conf[qualityLevel].quality;
subsampling = conf[qualityLevel].subsampling;
} else {
quality = -1;
subsampling = subsampleUndefined;
}
// Fine settings trump level
if (fineQuality != -1)
quality = fineQuality;
if (fineSubsampling != subsampleUndefined)
subsampling = fineSubsampling;
jc.clear();
jc.compress(buffer, stride, pb->getRect(),
pb->getPF(), quality, subsampling);
os = conn->getOutStream();
os->writeU8(tightJpeg << 4);
writeCompact(jc.length(), os);
os->writeBytes(jc.data(), jc.length());
}
void TightJPEGEncoder::writeSolidRect(int width, int height,
const PixelFormat& pf,
const rdr::U8* colour)
{
// FIXME: Add a shortcut in the JPEG compressor to handle this case
// without having to use the default fallback which is very slow.
Encoder::writeSolidRect(width, height, pf, colour);
}
void TightJPEGEncoder::writeCompact(rdr::U32 value, rdr::OutStream* os)
{
// Copied from TightEncoder as it's overkill to inherit just for this
rdr::U8 b;
b = value & 0x7F;
if (value <= 0x7F) {
os->writeU8(b);
} else {
os->writeU8(b | 0x80);
b = value >> 7 & 0x7F;
if (value <= 0x3FFF) {
os->writeU8(b);
} else {
os->writeU8(b | 0x80);
os->writeU8(value >> 14 & 0xFF);
}
}
}
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