以前在手机上用qt做过一个基于libflash的flash播放器，现在项目里播放功能用其他方案，但是要知道flash文件播放的帧数和帧率等参数，直接把libflash搬过来有点太夸张了，所以还是自己分析二进制文件吧 flash文件头的结构参考 http://sealbird.iteye.com/blog/1258904 由于手头上flash文件不多，试过 压缩过的flash10文件，正常。对于解压部分提供了2种选择，即zlib和qUncompress。qUncompress的话若不是解压用qCompress压缩的数据，则要在头部加入4个字节的解压后长度信息。 文件头中rect数据段的各参数读取最麻烦，要一位位读取，而不是平时用的字节为单位，而且有多少为还不是固定的。这里用了标准库里的std::bitset来存取这些数据，蛮方便。话说 QBitArray竟然没提供像std::bitset的to_ulong()这样实用的函数，那这个QBitArray有什么用我还真想不出。std::bitset有点不好，就是它是个模板，大小要预先定好。QBitArray可以动态分配大小，就缺一个转换到整型的函数，否则就用它了。 话说这么个简单的东西也写得我蛮累的，囧。直接上代码吧 头文件qflashinfo.h - /******************************************************************************
QFlashInfo: read flash information from file head
Copyright (C) 2011 Wang Bin <wbsecg1@gmail.com>
This program 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 program 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 program; if not, write to the Free Software Foundation, Inc.,
51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA.
******************************************************************************/
#ifndef QFLASHINFO_H
#define QFLASHINFO_H
#include <QtCore/QString>
class QFlashInfo
{
public:
QFlashInfo(const QString& fileName);
bool parse();
int getPlayTimeUSec() const;
int getTotalFrames() const;
float getFrameRate() const;
void showInfo();
private:
QString file_name; // SWF file analyzed
QByteArray magic; // Magic in a SWF file (FWS or CWS)
bool compressed; // Flag to indicate a compressed file (CWS)
char version; // Flash version
size_t file_size, uncompressed_size; // Uncompressed file size (in bytes)
int xmin, xmax, ymin, ymax; //Rect. width = xmax - xmin, height = ymax - ymin
int width; // Flash movie native width
int height; // Flash movie native height
float frame_rate;
bool valid; // Valid SWF file
int frames; // Flash movie total frames
};
#endif // QFLASHINFO_H
源文件qflashinfo.cpp - /******************************************************************************
QFlashInfo: read flash information from file head
Copyright (C) 2011 Wang Bin <wbsecg1@gmail.com>
This program 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 program 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 program; if not, write to the Free Software Foundation, Inc.,
51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA.
******************************************************************************/
#include "qflashinfo.h"
#define USE_ZLIB 0
#include <bitset>
#include <QtCore/QByteArray>
#include <QtCore/QFile>
#include <QtDebug>
#if USE_ZLIB
#include <zlib.h>
#endif //USE_ZLIB
QFlashInfo::QFlashInfo(const QString& fileName)
:file_name(fileName)
{
valid = compressed = false;
file_size = uncompressed_size = 0;
xmin = xmax = ymin = ymax =0;
width = height = 0;
frames = 0;
frame_rate = 0.;
}
bool QFlashInfo::parse()
{
QFile file(file_name);
if (!file.open(QIODevice::ReadOnly)) {
qDebug("Failed to open %s: %s", qPrintable(file_name), qPrintable(file.errorString()));
return false;
}
file_size = file.size();
magic = file.read(3);
if (magic != "FWS" && magic != "CWS") {
valid = false;
return valid;
}
//CWS: data from the 9th byte are compressed by zlib
compressed = (magic[0] == 'C');
version = file.read(1)[0] & 0xff; //not toInt(), why?
/*!
FWS: size == file size
CWS: size == file uncompressed size
*/
uncompressed_size = 0 ;
for (int i=0; i<4; ++i) {
char t = file.read(1)[0];
int s = t & 0xff;
//s = file.read(1).toInt(); //?
uncompressed_size += (s << (i << 3)) ;
}
// RECT
QByteArray buffer = file.read(file_size - 8);
QByteArray *uncompressed_data = &buffer;
file.close();
#if USE_ZLIB
if (compressed) {
ulong len = uncompressed_size - 8 ;
uncompressed_data = new QByteArray(len, 0);
// First decompress GZ stream
int res = uncompress((Bytef*)uncompressed_data->data(), (uLongf*)&uncompressed_size, (Bytef*)buffer.constData(), file_size - 8);
switch (res) {
case Z_MEM_ERROR: printf("Z_MEM_ERROR\n"); break;
case Z_BUF_ERROR: printf("Z_BUF_ERROR\n"); break;
case Z_DATA_ERROR: printf("Z_DATA_ERROR\n"); break;
}
}
#else
if (compressed) {
file.open(QIODevice::ReadOnly);
buffer.clear();
buffer = file.readAll();
file.close();
buffer.remove(0, 4);
ulong len = uncompressed_size - 8 ;
buffer[0] = (len & 0xff000000) >> 24;
buffer[1] = (len & 0x00ff0000) >> 16;
buffer[2] = (len & 0x0000ff00) >> 8;
buffer[3] = (len & 0x000000ff);
uncompressed_data = new QByteArray(qUncompress(buffer));
}
#endif //USE_ZLIB
char *p_data = uncompressed_data->data();
//The first 5 is the bits of he next 4 point store
int bits_per_value = *p_data & 0xff;
bits_per_value >>= 3; //RECT field size //bits
bits_per_value &= 0xff;
printf("bits per point: %d\n", bits_per_value);
std::bitset<32> rect_point; //32?
//read bit by bit.
int t = (*p_data & 0xff);
int byte_current = (t << 5) & 0xff;
// Current bit (first byte starts off already shifted)
int bits_remain = 2;
//get all 4 values in the RECT
for (int i = 0; i<4; ++i) {
int bit_index = 0;
while (bit_index < bits_per_value) {
rect_point[bit_index] = byte_current & 128; //1000000, get the highest bit
++bit_index;
byte_current <<= 1;
--bits_remain;
// We will be needing a new byte if we run out of bits
if (bits_remain < 0) {
byte_current = (int)(0xff & *++p_data);
bits_remain = 7;
}
}
int value = rect_point.to_ulong();
printf("bits %6d: %s\n", value, rect_point.to_string().c_str());
rect_point.reset();
switch (i) {
case 0: xmin = value; break;
case 1: xmax = value; break;
case 2: ymin = value; break;
case 3: ymax = value; break;
}
}
// Frame rate
int fractional_hex = (int)(*++p_data);
int integer_hex = (int)(*++p_data);
frame_rate = integer_hex + (float)fractional_hex/(float)(1<<8);
// Frames. Little-Endian
frames = 0xff & *++p_data;
frames += (int)(0xff & *++p_data) << 8;
valid = true;
return valid ;
}
int QFlashInfo::getPlayTimeUSec() const
{
return (frames * 1000)/frame_rate;
}
int QFlashInfo::getTotalFrames() const
{
return frames;
}
float QFlashInfo::getFrameRate() const
{
return frame_rate;
}
void QFlashInfo::showInfo()
{
printf("File: %s. Is valid swf: %d\n"
"Magic: %s. Compressed: %d. Version: %d\n"
"File size: %d. Uncompressed size: %d\n"
"x: %d - %d, y: %d - %d\n"
"width: %d. height: %d\n"
"Frames: %d. Frame rate: %f(fps). Time: %d(us)\n"
, qPrintable(file_name), valid
, magic.constData(), compressed, version
, file_size, uncompressed_size
, xmin, xmax, ymin, ymax
, xmax - xmin, ymax - ymin
, frames, frame_rate, getPlayTimeUSec());
}
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