问题
When I use the mpeg4 or h264 encoders, I am able to successfully encode images to make a valid AVI file using the API for ffmpeg 3.1.0. However, when I use the Quick Sync encoder (h264_qsv), avcodec_encode_video2 will hang some of the time. I found that when using images that are 1920x1080, it was rare that avcodec_encode_video2 would hang. When using 256x256 images, it was very likely that the function would hang.
I have created the test code below that demonstrates the hang of avcodec_encode_video2. The code will create a 1000 frame, 256x256 AVI with a bit rate of 400000. The frames are simply allocated, so the output video should just be green frames.
The problem was observed using Windows 7 and Windows 10, using the 32-bit or 64-bit test application.
If anyone has any idea on how I can avoid the avcodec_encode_video2 hang I would be very grateful! Thanks in advance for any assistance.
extern "C"
{
#ifndef __STDC_CONSTANT_MACROS
#define __STDC_CONSTANT_MACROS
#endif
#include "avcodec.h"
#include "avformat.h"
#include "swscale.h"
#include "avutil.h"
#include "imgutils.h"
#include "opt.h"
#include <rational.h>
}
#include <iostream>
// Globals
AVCodec* m_pCodec = NULL;
AVStream *m_pStream = NULL;
AVOutputFormat* m_pFormat = NULL;
AVFormatContext* m_pFormatContext = NULL;
AVCodecContext* m_pCodecContext = NULL;
AVFrame* m_pFrame = NULL;
int m_frameIndex;
// Output format
AVPixelFormat m_pixType = AV_PIX_FMT_NV12;
// Use for mpeg4
//AVPixelFormat m_pixType = AV_PIX_FMT_YUV420P;
// Output frame rate
int m_frameRate = 30;
// Output image dimensions
int m_imageWidth = 256;
int m_imageHeight = 256;
// Number of frames to export
int m_frameCount = 1000;
// Output file name
const char* m_fileName = "c:/test/test.avi";
// Output file type
const char* m_fileType = "AVI";
// Codec name used to encode
const char* m_encoderName = "h264_qsv";
// use for mpeg4
//const char* m_encoderName = "mpeg4";
// Target bit rate
int m_targetBitRate = 400000;
void addVideoStream()
{
m_pStream = avformat_new_stream( m_pFormatContext, m_pCodec );
m_pStream->id = m_pFormatContext->nb_streams - 1;
m_pStream->time_base = m_pCodecContext->time_base;
m_pStream->codec->pix_fmt = m_pixType;
m_pStream->codec->flags = m_pCodecContext->flags;
m_pStream->codec->width = m_pCodecContext->width;
m_pStream->codec->height = m_pCodecContext->height;
m_pStream->codec->time_base = m_pCodecContext->time_base;
m_pStream->codec->bit_rate = m_pCodecContext->bit_rate;
}
AVFrame* allocatePicture( enum AVPixelFormat pix_fmt, int width, int height )
{
AVFrame *frame;
frame = av_frame_alloc();
if ( !frame )
{
return NULL;
}
frame->format = pix_fmt;
frame->width = width;
frame->height = height;
int checkImage = av_image_alloc( frame->data, frame->linesize, width, height, pix_fmt, 32 );
if ( checkImage < 0 )
{
return NULL;
}
return frame;
}
bool initialize()
{
AVRational frameRate;
frameRate.den = m_frameRate;
frameRate.num = 1;
av_register_all();
m_pCodec = avcodec_find_encoder_by_name(m_encoderName);
if( !m_pCodec )
{
return false;
}
m_pCodecContext = avcodec_alloc_context3( m_pCodec );
m_pCodecContext->width = m_imageWidth;
m_pCodecContext->height = m_imageHeight;
m_pCodecContext->time_base = frameRate;
m_pCodecContext->gop_size = 0;
m_pCodecContext->pix_fmt = m_pixType;
m_pCodecContext->codec_id = m_pCodec->id;
m_pCodecContext->bit_rate = m_targetBitRate;
av_opt_set( m_pCodecContext->priv_data, "+CBR", "", 0 );
return true;
}
bool startExport()
{
m_frameIndex = 0;
char fakeFileName[512];
int checkAllocContext = avformat_alloc_output_context2( &m_pFormatContext, NULL, m_fileType, fakeFileName );
if ( checkAllocContext < 0 )
{
return false;
}
if ( !m_pFormatContext )
{
return false;
}
m_pFormat = m_pFormatContext->oformat;
if ( m_pFormat->video_codec != AV_CODEC_ID_NONE )
{
addVideoStream();
int checkOpen = avcodec_open2( m_pCodecContext, m_pCodec, NULL );
if ( checkOpen < 0 )
{
return false;
}
m_pFrame = allocatePicture( m_pCodecContext->pix_fmt, m_pCodecContext->width, m_pCodecContext->height );
if( !m_pFrame )
{
return false;
}
m_pFrame->pts = 0;
}
int checkOpen = avio_open( &m_pFormatContext->pb, m_fileName, AVIO_FLAG_WRITE );
if ( checkOpen < 0 )
{
return false;
}
av_dict_set( &(m_pFormatContext->metadata), "title", "QS Test", 0 );
int checkHeader = avformat_write_header( m_pFormatContext, NULL );
if ( checkHeader < 0 )
{
return false;
}
return true;
}
int processFrame( AVPacket& avPacket )
{
avPacket.stream_index = 0;
avPacket.pts = av_rescale_q( m_pFrame->pts, m_pStream->codec->time_base, m_pStream->time_base );
avPacket.dts = av_rescale_q( m_pFrame->pts, m_pStream->codec->time_base, m_pStream->time_base );
m_pFrame->pts++;
int retVal = av_interleaved_write_frame( m_pFormatContext, &avPacket );
return retVal;
}
bool exportFrame()
{
int success = 1;
int result = 0;
AVPacket avPacket;
av_init_packet( &avPacket );
avPacket.data = NULL;
avPacket.size = 0;
fflush(stdout);
std::cout << "Before avcodec_encode_video2 for frame: " << m_frameIndex << std::endl;
success = avcodec_encode_video2( m_pCodecContext, &avPacket, m_pFrame, &result );
std::cout << "After avcodec_encode_video2 for frame: " << m_frameIndex << std::endl;
if( result )
{
success = processFrame( avPacket );
}
av_packet_unref( &avPacket );
m_frameIndex++;
return ( success == 0 );
}
void endExport()
{
int result = 0;
int success = 0;
if (m_pFrame)
{
while ( success == 0 )
{
AVPacket avPacket;
av_init_packet( &avPacket );
avPacket.data = NULL;
avPacket.size = 0;
fflush(stdout);
success = avcodec_encode_video2( m_pCodecContext, &avPacket, NULL, &result );
if( result )
{
success = processFrame( avPacket );
}
av_packet_unref( &avPacket );
if (!result)
{
break;
}
}
}
if (m_pFormatContext)
{
av_write_trailer( m_pFormatContext );
if( m_pFrame )
{
av_frame_free( &m_pFrame );
}
avio_closep( &m_pFormatContext->pb );
avformat_free_context( m_pFormatContext );
m_pFormatContext = NULL;
}
}
void cleanup()
{
if( m_pFrame || m_pCodecContext )
{
if( m_pFrame )
{
av_frame_free( &m_pFrame );
}
if( m_pCodecContext )
{
avcodec_close( m_pCodecContext );
av_free( m_pCodecContext );
}
}
}
int main()
{
bool success = true;
if (initialize())
{
if (startExport())
{
for (int loop = 0; loop < m_frameCount; loop++)
{
if (!exportFrame())
{
std::cout << "Failed to export frame\n";
success = false;
break;
}
}
endExport();
}
else
{
std::cout << "Failed to start export\n";
success = false;
}
cleanup();
}
else
{
std::cout << "Failed to initialize export\n";
success = false;
}
if (success)
{
std::cout << "Successfully exported file\n";
}
return 1;
}
回答1:
The problem no longer occurs now that I have updated to the latest Intel® Graphics Driver (version 15.45.10.4542)
来源：https://stackoverflow.com/questions/38109576/ffmpeg-avcodec-encode-video2-hangs-when-using-quick-sync-h264-qsv-encoder