我正在使用live555和ffmpeg库从服务器获取和解码RTP H264流;视频流由ffmpeg编码，使用Baseline profile和
x264_param_default_preset(m_params, "veryfast", "zerolatency")
我读了this topic并在每帧中添加了SPS和PPS数据，这是我从网络收到的;
void ClientSink::NewFrameHandler(unsigned frameSize, unsigned numTruncatedBytes,
timeval presentationTime, unsigned durationInMicroseconds)
{
...
EncodedFrame tmp;
tmp.m_frame = std::vector<unsigned char>(m_tempBuffer.data(), m_tempBuffer.data() + frameSize);
tmp.m_duration = durationInMicroseconds;
tmp.m_pts = presentationTime;
//Add SPS and PPS data into the frame; TODO: some devices may send SPS and PPs data already into frame;
tmp.m_frame.insert(tmp.m_frame.begin(), m_spsPpsData.cbegin(), m_spsPpsData.cend());
emit newEncodedFrame( SharedEncodedFrame(tmp) );
m_frameCounter++;
this->continuePlaying();
}
我在解码器中收到这些帧。
bool H264Decoder::decodeFrame(SharedEncodedFrame orig_frame)
{
...
while(m_packet.size > 0)
{
int got_picture;
int len = avcodec_decode_video2(m_decoderContext, m_picture, &got_picture, &m_packet);
if (len < 0)
{
emit criticalError(QString("Decoding error"));
return false;
}
if (got_picture)
{
std::vector<unsigned char> result;
this->storePicture(result);
if ( m_picture->format == AVPixelFormat::AV_PIX_FMT_YUV420P )
{
//QImage img = QImage(result.data(), m_picture->width, m_picture->height, QImage::Format_RGB888);
Frame_t result_rgb;
if (!convert_yuv420p_to_rgb32(result, m_picture->width, m_picture->height, result_rgb))
{
emit criticalError( QString("Failed to convert YUV420p image into rgb32; can't create QImage!"));
return false;
}
unsigned char* copy_img = new unsigned char[result_rgb.size()];
//this needed because QImage shared buffer, which used, and it will crash, if i use this qimage after result_rgb deleting
std::copy(result_rgb.cbegin(), result_rgb.cend(), copy_img);
QImage img = QImage(copy_img, m_picture->width, m_picture->height, QImage::Format_RGB32,
[](void* array)
{
delete[] array;
}, copy_img);
img.save(QString("123.bmp"));
emit newDecodedFrame(img);
}
avcodec_decode_video2解码没有任何错误消息的帧，但解码后的帧（从yuv420p转换为rgb32）无效。 this link
上提供的图片示例你有什么想法我错了吗？
答案 0 :(得分：5)
我怀疑错误发生在convert_yuv420p_to_rgb32（）代码中。试试这个：
static SwsContext *m_swsCtx = NULL;
QImage frame = QImage ( m_picture->width, m_picture->height,
QImage::Format_RGB32 );
m_swsCtx = sws_getCachedContext ( m_swsCtx, m_picture->width,
m_picture->height, PIX_FMT_YUV420P,
m_picture->width, m_picture->height,
AV_PIX_FMT_RGB32, SWS_BICUBIC,
NULL, NULL, NULL );
uint8_t *dstSlice[] = { frame.bits() };
int dstStride = frame.width() * 4;
sws_scale ( m_swsCtx, &m_picture.data, &m_picture.linesize,
0, m_picture->height, dstSlice, &dstStride );
如果您还没有这样做，则需要包含/链接swscale。
注意：每帧都不需要SPS / PPS（在关键帧上足够好）。但它也没有伤害。
答案 1 :(得分：4)
确定。这是我的简单示例，它解码从liveMedia库收到的H264流。它可以解码帧，这些帧不仅在帧的边界处被截断。
class H264Decoder : public AbstractDecoder
{
Q_OBJECT
public:
H264Decoder( QObject* parent = nullptr );
virtual ~H264Decoder();
public slots:
virtual bool decodeFrame(SharedEncodedFrame orig_frame) override;
signals:
//sended when we have new decoded frame
void newDecodedFrame( QImage img );
protected:
void storePicture(std::vector<unsigned char>& res);
AVCodec* m_decoder;
AVCodecContext* m_decoderContext;
int m_got_picture;
AVFrame* m_picture;
AVPacket m_packet;
};
这是实现：
#include "H264Decoder.hpp"
#include "ImgConverting.hpp"
#include <QPixmap>
extern "C"
{
#include <libswscale/swscale.h>
}
using namespace std;
H264Decoder::H264Decoder( QObject *parent)
: AbstractDecoder(parent), m_decoder(nullptr), m_decoderContext(nullptr),
m_got_picture(0), m_picture(nullptr)
{
avcodec_register_all();
av_init_packet(&m_packet);
m_decoder = avcodec_find_decoder(CODEC_ID_H264);
if (!m_decoder)
{
QString str = QString("Can't find H264 decoder!");
emit criticalError(str);
}
m_decoderContext = avcodec_alloc_context3(m_decoder);
if (m_decoder->capabilities & CODEC_CAP_TRUNCATED)
m_decoderContext->flags |= CODEC_FLAG_TRUNCATED;
//we can receive truncated frames
m_decoderContext->flags2 |= CODEC_FLAG2_CHUNKS;
m_decoderContext->thread_count = 4;//TODO: random value. May be changing can make decoding faster
AVDictionary* dictionary = nullptr;
if (avcodec_open2(m_decoderContext, m_decoder, &dictionary) < 0)
{
QString str = QString("Failed to open decoder!");
emit criticalError(str);
}
qDebug() << "H264 Decoder successfully opened";
m_picture = avcodec_alloc_frame();
}
H264Decoder::~H264Decoder()
{
qDebug() << "ACHTUNG!!! H264Decoder deleted!!!\r\n\r\n";
if (m_decoderContext)
{
avcodec_close(m_decoderContext);
delete m_decoderContext;
}
}
bool H264Decoder::decodeFrame(SharedEncodedFrame orig_frame)
{
Frame_t enc_frame;
orig_frame >> enc_frame;
m_packet.size = enc_frame.size();
m_packet.data = enc_frame.data();
qDebug() << "H264Decoder: received encoded frame with framesize " << enc_frame.size();
while(m_packet.size > 0)
{
int got_picture;
int len = avcodec_decode_video2(m_decoderContext, m_picture, &got_picture, &m_packet);
if (len < 0)
{
QString err("Decoding error");
qDebug() << err;
return false;
}
if (got_picture)
{
qDebug() << "H264Decoder: frame decoded!";
std::vector<unsigned char> result;
this->storePicture(result);
if ( m_picture->format == PIX_FMT_YUV420P )
{
static SwsContext *m_swsCtx = NULL;
QImage frame_img = QImage(m_picture->width, m_picture->height, QImage::Format_RGB888);
m_swsCtx = sws_getCachedContext ( m_swsCtx, m_picture->width,
m_picture->height, PIX_FMT_YUV420P,
m_picture->width, m_picture->height,
PIX_FMT_RGB24, SWS_GAUSS,
NULL, NULL, NULL );
uint8_t *dstSlice[] = { frame_img.bits() };
int dstStride = frame_img.width() * 3;
if (sws_scale ( m_swsCtx, m_picture->data, m_picture->linesize,
0, m_picture->height, dstSlice, &dstStride ) != m_picture->height )
{
qDebug() << "PIZDETS!!!";
exit(-5);
}
qDebug() << "New decoded image!";
emit newDecodedFrame(frame_img);
}
else if (m_picture->format == PIX_FMT_RGB32)
{
QImage img = QImage(result.data(), m_picture->width, m_picture->height, QImage::Format_RGB32);
qDebug() << "New decoded image!";
emit newDecodedFrame(img);
}
else if (m_picture->format == PIX_FMT_RGB24)
{
QImage img = QImage(result.data(), m_picture->width, m_picture->height, QImage::Format_RGB888);
qDebug() << "New decoded image!";
emit newDecodedFrame(img);
}
else
{
QString err = QString( "Unsupported pixel format! Can't create QImage!");
qDebug() << err;
emit criticalError( err );
return false;
}
}
m_packet.size -= len;
m_packet.data += len;
}
return true;
}
void H264Decoder::storePicture(std::vector<unsigned char>& res)
{
for (size_t i = 0; i < AV_NUM_DATA_POINTERS; i++)
{
std::copy(m_picture->data[i], m_picture->data[i] +
m_picture->linesize[i]*m_picture->height, std::back_inserter(res));
}
}
我将newDecodedFrame发送到GUI线程，其中将在某个小部件上绘制此QImage。
P.S：这条评论很长，可以发表评论的评论