Hello everyone,
i'm trying to decode my Hevc file in c++ with using FFmpeg. I used Hevc decoder
and try to save the frames in ppm format. My Hevc file has 677 frames, which i
checked with ffprobe in command window. But i any got 676 frames with my
project. Also i have checked with other Hevc files, the results are same, i got
always one frame less. And i assumed that, that could happy in the position,
which at last phase i tried to flush the decoder. That means, that could be 3
frames in the decoder to be flush, but i got only 2 frames.
Can anybody help me, i attach my cpp file and add a link to the whole project
files. What you need is to define test file path and output directory for saved
images. Which are for me like that:
D:\Workspace\TestProjects\FFmpegDecoder\TestFiles\sample_1280x720.hevc
D:\Workspace\TestProjects\FFmpegDecoder\Output
Thanks a lot!
Best regards,
Ivan
[https://outlook-2.cdn.office.net/assets/mail/file-icon/png/zip_16x16.png]FFmpegDecoder.zip<https://1drv.ms/u/s!AgIaR65lMcbzgiw7OsY4WG5yVoUV>
#include <iostream>
#include <string>
extern "C"
{
#include "../Headers/libavcodec/avcodec.h"
#include "../Headers/libavformat/avformat.h"
#include "../Headers/libswscale/swscale.h"
}
#define INBUF_SIZE 4096
//Save RGB image as PPM file format
static void ppm_save(char* filename, AVFrame* frame)
{
FILE* file;
int i;
fopen_s(&file, filename, "wb");
fprintf(file, "P6\n%d %d\n%d\n", frame->width, frame->height, 255);
for (i = 0; i < frame->height; i++)
fwrite(frame->data[0] + i * frame->linesize[0], 1, frame->width
* 3, file);
fclose(file);
}
void decode(AVCodecContext* dec_ctx, AVFrame* frame, AVPacket* pkt, const char*
outputDirectory)
{
char buf[1024];
int ret;
ret = avcodec_send_packet(dec_ctx, pkt);
if (ret < 0) {
fprintf(stderr, "Error sending a packet for decoding\n");
exit(1);
}
int sts;
////////////////////////////////////////////////////////////////////////////
//Create SWS Context for converting from decode pixel format (like
YUV420) to RGB
struct SwsContext* sws_ctx = NULL;
sws_ctx = sws_getContext(dec_ctx->width,
dec_ctx->height,
dec_ctx->pix_fmt,
dec_ctx->width,
dec_ctx->height,
AV_PIX_FMT_RGB24,
SWS_BICUBIC,
NULL,
NULL,
NULL);
if (sws_ctx == nullptr)
{
return; //Error!
}
//Allocate frame for storing image converted to RGB.
AVFrame* pRGBFrame = av_frame_alloc();
pRGBFrame->format = AV_PIX_FMT_RGB24;
pRGBFrame->width = dec_ctx->width;
pRGBFrame->height = dec_ctx->height;
sts = av_frame_get_buffer(pRGBFrame, 0);
if (sts < 0)
{
goto free;
//return; //Error!
}
while (ret >= 0)
{
ret = avcodec_receive_frame(dec_ctx, frame);
if (ret == AVERROR(EAGAIN) || ret == AVERROR_EOF)
goto free;
//return;
else if (ret < 0) {
fprintf(stderr, "Error during decoding\n");
exit(1);
}
//Õý³£Çé¿ö
printf("saving frame %3d\n", dec_ctx->frame_number);//
fflush(stdout);
//////////////////////////////////////////////////////////////////////////
//Convert from input format (e.g YUV420) to RGB and save to PPM:
sts = sws_scale(sws_ctx, //struct SwsContext* c,
frame->data, //const uint8_t* const
srcSlice[],
frame->linesize, //const int srcStride[],
0, //int srcSliceY,
frame->height, //int srcSliceH,
pRGBFrame->data, //uint8_t* const dst[],
pRGBFrame->linesize); //const int dstStride[]);
snprintf(buf, sizeof(buf), "%s\\%s%d.ppm", outputDirectory,
"Output-", dec_ctx->frame_number);
ppm_save(buf, pRGBFrame);
}
free:
//Free
////////////////////////////////////////////////////////////////////////////
sws_freeContext(sws_ctx);
av_frame_free(&pRGBFrame);
}
int main(int argc, char** argv)
{
const char* filename, * outputDirectory, * seqfilename;
const AVCodec* codec;
AVCodecParserContext* parser;
AVCodecContext* codecContext = NULL;
FILE* file;
AVFrame* frame;
uint8_t inbuf[INBUF_SIZE + AV_INPUT_BUFFER_PADDING_SIZE];
uint8_t* data;
size_t data_size;
int ret;
AVPacket* pkt;
std::cout << "Test file full path:";
std::string inputFilename;
std::getline(std::cin, inputFilename);
filename = const_cast<char*>(inputFilename.c_str());
std::string inputOutput;
std::cout << "Directory for output images:";
std::getline(std::cin, inputOutput);
outputDirectory = const_cast<char*>(inputOutput.c_str());
pkt = av_packet_alloc();
if (!pkt)
exit(1);
/* set end of buffer to 0 (this ensures that no overreading happens for
damaged MPEG streams) */
memset(inbuf + INBUF_SIZE, 0, AV_INPUT_BUFFER_PADDING_SIZE);
/* find the HEVC video decoder */
codec = avcodec_find_decoder(AV_CODEC_ID_HEVC);
if (!codec) {
fprintf(stderr, "Codec not found\n");
exit(1);
}
parser = av_parser_init(codec->id);
if (!parser) {
fprintf(stderr, "parser not found\n");
exit(1);
}
codecContext = avcodec_alloc_context3(codec);
if (!codecContext) {
fprintf(stderr, "Could not allocate video codec context\n");
exit(1);
}
/* For some codecs, such as msmpeg4 and mpeg4, width and height
MUST be initialized there because this information is not
available in the bitstream. */
/* open it */
if (avcodec_open2(codecContext, codec, NULL) < 0) {
fprintf(stderr, "Could not open codec\n");
exit(1);
}
fopen_s(&file, filename, "rb");
if (!file) {
fprintf(stderr, "Could not open %s\n", filename);
exit(1);
}
frame = av_frame_alloc();
if (!frame) {
fprintf(stderr, "Could not allocate video frame\n");
exit(1);
}
while (!feof(file)) {
/* read raw data from the input file */
data_size = fread(inbuf, 1, INBUF_SIZE, file);
if (!data_size)
break;
/* use the parser to split the data into frames */
data = inbuf;
while (data_size > 0)
{
ret = av_parser_parse2(parser, codecContext,
&pkt->data, &pkt->size,
data, data_size, AV_NOPTS_VALUE,
AV_NOPTS_VALUE, 0);
if (ret < 0) {
fprintf(stderr, "Error while parsing\n");
exit(1);
}
data += ret;
data_size -= ret;
if (pkt->size)
decode(codecContext, frame, pkt,
outputDirectory);
}
}
/* flush the decoder */
decode(codecContext, frame, NULL, outputDirectory);
fclose(file);
av_parser_close(parser);
avcodec_free_context(&codecContext);
av_frame_free(&frame);
av_packet_free(&pkt);
return 0;
}_______________________________________________
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![https://outlook-2.cdn.office.net/assets/mail/file-icon/png/zip_16x16.png]FFmpegDecoder.zip](https://outlook-2.cdn.office.net/assets/mail/file-icon/png/zip_16x16.png]FFmpegDecoder.zip){kind=link}