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L’utiliser, en parler, le critiquer
10 avril 2011La première attitude à adopter est d’en parler, soit directement avec les personnes impliquées dans son développement, soit autour de vous pour convaincre de nouvelles personnes à l’utiliser.
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13 avril 2011Documentation is vital to the development of improved technical capabilities.
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Sur d’autres sites (4218)
-
How can i save a iphone uploaded video always horizontal by ffmpeg
24 juillet 2013, par Ranjith ReddyI am using FFMPEG for uploading recording video from iphone and generating frames.
case1 : recording video in horizontal (generating video and frames in horizontal).
case2 : recording video in vertical (generating video and frames in vertical).
But in above 2 case i want video and frames in horizontal only.
FFMPEG COMMAND
%x(cd "#{tmp_path}" && ffmpeg -i "video path" -r 1 -f image2 image-%4d.jpeg ) -
Why there is no AVFrame->data[2] data when decode h264 by ffmpeg use "h264_cuvid"
27 juillet 2017, par Wu NLenv : ubuntu 16.04 64 bit ; ffmpeg 3.3.2 build whih cuda cuvid libnpp...
use ffmpeg cmd :ffmpeg -vsync 0 -c:v h264_cuvid -i test.264 -f rawvideo test.yuvworks fine, the generated yuv file is ok.
BUT When I decode this 264 file by my code use ’h264_cuvid’ decoder, something problem happens, this is my code :#include
#define __STDC_CONSTANT_MACROS
#ifdef _WIN32
//Windows
extern "C"
{
#include "libavcodec/avcodec.h"
};
#else
//Linux...
#ifdef __cplusplus
extern "C"
{
#endif
#include <libavcodec></libavcodec>avcodec.h>
#ifdef __cplusplus
};
#endif
#endif
//test different codec
#define TEST_H264 1
#define TEST_HEVC 0
int main(int argc, char* argv[])
{
AVCodec *pCodec;
AVCodecContext *pCodecCtx= NULL;
AVCodecParserContext *pCodecParserCtx=NULL;
FILE *fp_in;
FILE *fp_out;
AVFrame *pFrame;
const int in_buffer_size=4096;
unsigned char in_buffer[in_buffer_size + FF_INPUT_BUFFER_PADDING_SIZE]= {0};
unsigned char *cur_ptr;
int cur_size;
AVPacket packet;
int ret, got_picture;
#if TEST_HEVC
enum AVCodecID codec_id=AV_CODEC_ID_HEVC;
char filepath_in[]="bigbuckbunny_480x272.hevc";
#elif TEST_H264
AVCodecID codec_id=AV_CODEC_ID_H264;
char filepath_in[]="2_60_265to264.264";
#else
AVCodecID codec_id=AV_CODEC_ID_MPEG2VIDEO;
char filepath_in[]="bigbuckbunny_480x272.m2v";
#endif
char filepath_out[]="mainSend.yuv";
int first_time=1;
//av_log_set_level(AV_LOG_DEBUG);
avcodec_register_all();
// pCodec = avcodec_find_decoder(codec_id);
pCodec = avcodec_find_decoder_by_name("h264_cuvid");
if (!pCodec)
{
printf("Codec not found\n");
return -1;
}
pCodecCtx = avcodec_alloc_context3(pCodec);
if (!pCodecCtx)
{
printf("Could not allocate video codec context\n");
return -1;
}
pCodecParserCtx=av_parser_init(pCodec->id);
if (!pCodecParserCtx)
{
printf("Could not allocate video parser context\n");
return -1;
}
if (avcodec_open2(pCodecCtx, pCodec, NULL) < 0)
{
printf("Could not open codec\n");
return -1;
}
//Input File
fp_in = fopen(filepath_in, "rb");
if (!fp_in)
{
printf("Could not open input stream\n");
return -1;
}
//Output File
fp_out = fopen(filepath_out, "wb");
if (!fp_out)
{
printf("Could not open output YUV file\n");
return -1;
}
pFrame = av_frame_alloc();
av_init_packet(&packet);
while (1)
{
cur_size = fread(in_buffer, 1, in_buffer_size, fp_in);
if (cur_size == 0)
break;
cur_ptr=in_buffer;
while (cur_size>0)
{
int len = av_parser_parse2(
pCodecParserCtx, pCodecCtx,
&packet.data, &packet.size,
cur_ptr, cur_size,
AV_NOPTS_VALUE, AV_NOPTS_VALUE, AV_NOPTS_VALUE);
cur_ptr += len;
cur_size -= len;
if(packet.size==0)
continue;
//Some Info from AVCodecParserContext
printf("[Packet]Size:%6d\t",packet.size);
switch(pCodecParserCtx->pict_type)
{
case AV_PICTURE_TYPE_I:
printf("Type:I\tNumber:%4d\n",pCodecParserCtx->output_picture_number);
break;
case AV_PICTURE_TYPE_P:
printf("Type:P\t");
break;
case AV_PICTURE_TYPE_B:
printf("Type:B\t");
break;
default:
printf("Type:Other\t");
break;
}
printf("Number:%4d\n",pCodecParserCtx->output_picture_number);
AVFrame* myFrame = av_frame_alloc();
ret = avcodec_decode_video2(pCodecCtx, myFrame, &got_picture, &packet);
if (ret < 0)
{
printf("Decode Error.\n");
return ret;
}
if (got_picture)
{
if(first_time)
{
printf("\nCodec Full Name:%s\n",pCodecCtx->codec->long_name);
printf("width:%d\nheight:%d\n\n",pCodecCtx->width,pCodecCtx->height);
first_time=0;
}
//Y, U, V
for(int i=0; iheight; i++)
{
fwrite(myFrame->data[0]+myFrag-g>linesize[0]*i,1,myFrame->width,fp_out);
}
for(int i=0; iheight/2; i++)
{
fwrite(myFrame->data[1]+myFrag-g>linesize[1]*i,1,myFrame->width/2,fp_out);
}
for(int i=0; iheight/2; i++)
{
fwrite(myFrame->data[2]+myFrag-g>linesize[2]*i,1,myFrame->width/2,fp_out);
}
// printf("pframe's width height %d %d\t key frame %d\n",myFrame->width,myFrame->height,myFrame->key_frame);
printf("Succeed to decode 1 frame!\n");
av_frame_free(&myFrame);
}
}
}
fclose(fp_in);
fclose(fp_out);
av_parser_close(pCodecParserCtx);
av_frame_free(&pFrame);
avcodec_close(pCodecCtx);
av_free(pCodecCtx);
return 0;
}In this demo code, I call h264_cuvid by
vcodec_find_decoder_by_name("h264_cuvid");
BUT the code crash atfwrite(myFrame->data[2]+myFrag-g>linesize[2]*i,1,myFrame->width/2,fp_out);
So after debug with codeblocks, I found that there is no data in myFrame->data[2] codeblocks watching windowAny suggestion ? thanks !
-
save a serial of images(cv::Mat) to a mp4 file in Variable Frame Rate mode by using ffmpeg library, how to set the pts ?
2 mai 2023, par ollydbg23In C++ code, I can correctly save a serial of images(opencv's
cv::Mat) to a mp4 file by usingffmpeglibrary, see the question and answer here : avformat_write_header() function call crashed when I try to save several RGB data to a output.mp4 file

Now here comes another question :


Rotem' answer in that question can have the
output.mp4saved correctly. When play the mp4 file, I see the frames(OpenCV'scv::Matimage) shows in a const rate.

What I can do if I have got the frames not in a const frequency, for example, the I got the first frame at the
0ms, and the second frame at the50msthe third frame at75ms, so that the each frame as associated time stamp, for example, those time stamp array are something like below :

int timestamp[100] = {0, 50, 75, ...};


What is the method to modify the Rotem's answer to reflect this ? It looks like I have to change the
ptsfield of eachframe. Because I just test the code, if I change this :

yuvFrame->pts = av_rescale_q(frame_count*frame_count, outCodecCtx->time_base, outStream->time_base); //Set PTS timestamp

// note I change from frame_count to frame_count*frame_count


Then the
output.mp4plays slower and slower, because the later frame has largeptsvalues.

Thanks.


EDIT


This is the code I'm currently used :


#include <iostream>
#include <vector>
#include <cstring>
#include <fstream>
#include <sstream>
#include <stdexcept>
#include <opencv2></opencv2>opencv.hpp>
extern "C" {
#include <libavutil></libavutil>imgutils.h>
#include <libavcodec></libavcodec>avcodec.h>
#include <libavformat></libavformat>avformat.h>
#include <libavutil></libavutil>opt.h>
}

#include<cstdlib> // to generate time stamps

using namespace std;
using namespace cv;

int main()
{
 // Set up input frames as BGR byte arrays
 vector<mat> frames;

 int width = 640;
 int height = 480;
 int num_frames = 100;
 Scalar black(0, 0, 0);
 Scalar white(255, 255, 255);
 int font = FONT_HERSHEY_SIMPLEX;
 double font_scale = 1.0;
 int thickness = 2;

 for (int i = 0; i < num_frames; i++) {
 Mat frame = Mat::zeros(height, width, CV_8UC3);
 putText(frame, std::to_string(i), Point(width / 2 - 50, height / 2), font, font_scale, white, thickness);
 frames.push_back(frame);
 }

 // generate a serial of time stamps which is used to set the PTS value
 // suppose they are in ms unit, the time interval is between 30ms to 59ms
 vector<int> timestamps;

 for (int i = 0; i < num_frames; i++) {
 int timestamp;
 if (i == 0)
 timestamp = 0;
 else
 {
 int random = 30 + (rand() % 30);
 timestamp = timestamps[i-0] + random;
 }

 timestamps.push_back(timestamp);
 }

 // Populate frames with BGR byte arrays

 // Initialize FFmpeg
 //av_register_all();

 // Set up output file
 AVFormatContext* outFormatCtx = nullptr;
 //AVCodec* outCodec = nullptr;
 AVCodecContext* outCodecCtx = nullptr;
 //AVStream* outStream = nullptr;
 //AVPacket outPacket;

 const char* outFile = "output.mp4";
 int outWidth = frames[0].cols;
 int outHeight = frames[0].rows;
 int fps = 25;

 // Open the output file context
 avformat_alloc_output_context2(&outFormatCtx, nullptr, nullptr, outFile);
 if (!outFormatCtx) {
 cerr << "Error: Could not allocate output format context" << endl;
 return -1;
 }

 // Open the output file
 if (avio_open(&outFormatCtx->pb, outFile, AVIO_FLAG_WRITE) < 0) {
 cerr << "Error opening output file" << std::endl;
 return -1;
 }

 // Set up output codec
 const AVCodec* outCodec = avcodec_find_encoder(AV_CODEC_ID_H264);
 if (!outCodec) {
 cerr << "Error: Could not find H.264 codec" << endl;
 return -1;
 }

 outCodecCtx = avcodec_alloc_context3(outCodec);
 if (!outCodecCtx) {
 cerr << "Error: Could not allocate output codec context" << endl;
 return -1;
 }
 outCodecCtx->codec_id = AV_CODEC_ID_H264;
 outCodecCtx->codec_type = AVMEDIA_TYPE_VIDEO;
 outCodecCtx->pix_fmt = AV_PIX_FMT_YUV420P;
 outCodecCtx->width = outWidth;
 outCodecCtx->height = outHeight;
 outCodecCtx->time_base = { 1, fps*1000 }; // 25000
 outCodecCtx->framerate = {fps, 1}; // 25
 outCodecCtx->bit_rate = 4000000;

 //https://github.com/leandromoreira/ffmpeg-libav-tutorial
 //We set the flag AV_CODEC_FLAG_GLOBAL_HEADER which tells the encoder that it can use the global headers.
 if (outFormatCtx->oformat->flags & AVFMT_GLOBALHEADER)
 {
 outCodecCtx->flags |= AV_CODEC_FLAG_GLOBAL_HEADER; //
 }

 // Open output codec
 if (avcodec_open2(outCodecCtx, outCodec, nullptr) < 0) {
 cerr << "Error: Could not open output codec" << endl;
 return -1;
 }

 // Create output stream
 AVStream* outStream = avformat_new_stream(outFormatCtx, outCodec);
 if (!outStream) {
 cerr << "Error: Could not allocate output stream" << endl;
 return -1;
 }

 // Configure output stream parameters (e.g., time base, codec parameters, etc.)
 // ...

 // Connect output stream to format context
 outStream->codecpar->codec_id = outCodecCtx->codec_id;
 outStream->codecpar->codec_type = AVMEDIA_TYPE_VIDEO;
 outStream->codecpar->width = outCodecCtx->width;
 outStream->codecpar->height = outCodecCtx->height;
 outStream->codecpar->format = outCodecCtx->pix_fmt;
 outStream->time_base = outCodecCtx->time_base;

 int ret = avcodec_parameters_from_context(outStream->codecpar, outCodecCtx);
 if (ret < 0) {
 cerr << "Error: Could not copy codec parameters to output stream" << endl;
 return -1;
 }

 outStream->avg_frame_rate = outCodecCtx->framerate;
 //outStream->id = outFormatCtx->nb_streams++; <--- We shouldn't modify outStream->id

 ret = avformat_write_header(outFormatCtx, nullptr);
 if (ret < 0) {
 cerr << "Error: Could not write output header" << endl;
 return -1;
 }

 // Convert frames to YUV format and write to output file
 int frame_count = -1;
 for (const auto& frame : frames) {
 frame_count++;
 AVFrame* yuvFrame = av_frame_alloc();
 if (!yuvFrame) {
 cerr << "Error: Could not allocate YUV frame" << endl;
 return -1;
 }
 av_image_alloc(yuvFrame->data, yuvFrame->linesize, outWidth, outHeight, AV_PIX_FMT_YUV420P, 32);

 yuvFrame->width = outWidth;
 yuvFrame->height = outHeight;
 yuvFrame->format = AV_PIX_FMT_YUV420P;

 // Convert BGR frame to YUV format
 Mat yuvMat;
 cvtColor(frame, yuvMat, COLOR_BGR2YUV_I420);
 memcpy(yuvFrame->data[0], yuvMat.data, outWidth * outHeight);
 memcpy(yuvFrame->data[1], yuvMat.data + outWidth * outHeight, outWidth * outHeight / 4);
 memcpy(yuvFrame->data[2], yuvMat.data + outWidth * outHeight * 5 / 4, outWidth * outHeight / 4);

 // Set up output packet
 //av_init_packet(&outPacket); //error C4996: 'av_init_packet': was declared deprecated
 AVPacket* outPacket = av_packet_alloc();
 memset(outPacket, 0, sizeof(outPacket)); //Use memset instead of av_init_packet (probably unnecessary).
 //outPacket->data = nullptr;
 //outPacket->size = 0;

 yuvFrame->pts = av_rescale_q(timestamps[frame_count], outCodecCtx->time_base, outStream->time_base); //Set PTS timestamp

 // Encode frame and write to output file
 int ret = avcodec_send_frame(outCodecCtx, yuvFrame);
 if (ret < 0) {
 cerr << "Error: Could not send frame to output codec" << endl;
 return -1;
 }
 while (ret >= 0) {
 ret = avcodec_receive_packet(outCodecCtx, outPacket);
 if (ret == AVERROR(EAGAIN) || ret == AVERROR_EOF) {
 break;
 } else if (ret < 0) {
 cerr << "Error: Could not receive packet from output codec" << endl;
 return -1;
 }

 //av_packet_rescale_ts(&outPacket, outCodecCtx->time_base, outStream->time_base);

 outPacket->stream_index = outStream->index;

 outPacket->duration = av_rescale_q(1, outCodecCtx->time_base, outStream->time_base); // Set packet duration

 ret = av_interleaved_write_frame(outFormatCtx, outPacket);
 av_packet_unref(outPacket);
 if (ret < 0) {
 cerr << "Error: Could not write packet to output file" << endl;
 return -1;
 }
 }

 av_frame_free(&yuvFrame);
 }

 // Flush the encoder
 ret = avcodec_send_frame(outCodecCtx, nullptr);
 if (ret < 0) {
 std::cerr << "Error flushing encoder: " << std::endl;
 return -1;
 }

 while (ret >= 0) {
 AVPacket* pkt = av_packet_alloc();
 if (!pkt) {
 std::cerr << "Error allocating packet" << std::endl;
 return -1;
 }
 ret = avcodec_receive_packet(outCodecCtx, pkt);

 // Write the packet to the output file
 if (ret == 0)
 {
 pkt->stream_index = outStream->index;
 pkt->duration = av_rescale_q(1, outCodecCtx->time_base, outStream->time_base); // <---- Set packet duration
 ret = av_interleaved_write_frame(outFormatCtx, pkt);
 av_packet_unref(pkt);
 if (ret < 0) {
 std::cerr << "Error writing packet to output file: " << std::endl;
 return -1;
 }
 }
 }


 // Write output trailer
 av_write_trailer(outFormatCtx);

 // Clean up
 avcodec_close(outCodecCtx);
 avcodec_free_context(&outCodecCtx);
 avformat_free_context(outFormatCtx);

 return 0;
}
</int></mat></cstdlib></stdexcept></sstream></fstream></cstring></vector></iostream>

Especially, I have those changes to the original Rotem's answer :


Fist, I have some code to generate a time stamp array :


// generate a serial of time stamps which is used to set the PTS value
 // suppose they are in ms unit, the time interval is between 30ms to 59ms
 vector<int> timestamps;

 for (int i = 0; i < num_frames; i++) {
 int timestamp;
 if (i == 0)
 timestamp = 0;
 else
 {
 int random = 30 + (rand() % 30);
 timestamp = timestamps[i-0] + random;
 }

 timestamps.push_back(timestamp);
 }
</int>

Second, I just set the PTS by those values :


yuvFrame->pts = av_rescale_q(timestamps[frame_count], outCodecCtx->time_base, outStream->time_base); //Set PTS timestamp


Note that I have set the fps like below :


outCodecCtx->time_base = { 1, fps*1000 }; // 25000
 outCodecCtx->framerate = {fps, 1}; // 25


Now, when I run the program, I got a lot of warnings in the console :


[libx264 @ 0000022e7fa621c0] using cpu capabilities: MMX2 SSE2Fast SSSE3 SSE4.2 AVX FMA3 BMI2 AVX2
[libx264 @ 0000022e7fa621c0] profile High, level 3.0, 4:2:0, 8-bit
[libx264 @ 0000022e7fa621c0] 264 - core 164 r3094M bfc87b7 - H.264/MPEG-4 AVC codec - Copyleft 2003-2022 - http://www.videolan.org/x264.html - options: cabac=1 ref=3 deblock=1:0:0 analyse=0x3:0x113 me=hex subme=7 psy=1 psy_rd=1.00:0.00 mixed_ref=1 me_range=16 chroma_me=1 trellis=1 8x8dct=1 cqm=0 deadzone=21,11 fast_pskip=1 chroma_qp_offset=-2 threads=6 lookahead_threads=1 sliced_threads=0 nr=0 decimate=1 interlaced=0 bluray_compat=0 constrained_intra=0 bframes=3 b_pyramid=2 b_adapt=1 b_bias=0 direct=1 weightb=1 open_gop=0 weightp=2 keyint=250 keyint_min=25 scenecut=40 intra_refresh=0 rc_lookahead=40 rc=abr mbtree=1 bitrate=4000 ratetol=1.0 qcomp=0.60 qpmin=0 qpmax=69 qpstep=4 ip_ratio=1.40 aq=1:1.00
[libx264 @ 0000022e7fa621c0] non-strictly-monotonic PTS
[libx264 @ 0000022e7fa621c0] non-strictly-monotonic PTS
[libx264 @ 0000022e7fa621c0] non-strictly-monotonic PTS
[libx264 @ 0000022e7fa621c0] non-strictly-monotonic PTS
[libx264 @ 0000022e7fa621c0] non-strictly-monotonic PTS
[libx264 @ 0000022e7fa621c0] non-strictly-monotonic PTS
[libx264 @ 0000022e7fa621c0] non-strictly-monotonic PTS
[libx264 @ 0000022e7fa621c0] non-strictly-monotonic PTS
[libx264 @ 0000022e7fa621c0] non-strictly-monotonic PTS
[libx264 @ 0000022e7fa621c0] non-strictly-monotonic PTS
[libx264 @ 0000022e7fa621c0] non-strictly-monotonic PTS
[libx264 @ 0000022e7fa621c0] non-strictly-monotonic PTS
[libx264 @ 0000022e7fa621c0] non-strictly-monotonic PTS
[libx264 @ 0000022e7fa621c0] non-strictly-monotonic PTS
[libx264 @ 0000022e7fa621c0] non-strictly-monotonic PTS
[libx264 @ 0000022e7fa621c0] non-strictly-monotonic PTS
[libx264 @ 0000022e7fa621c0] non-strictly-monotonic PTS
[libx264 @ 0000022e7fa621c0] non-strictly-monotonic PTS
[libx264 @ 0000022e7fa621c0] non-strictly-monotonic PTS
[libx264 @ 0000022e7fa621c0] non-strictly-monotonic PTS
[libx264 @ 0000022e7fa621c0] non-strictly-monotonic PTS
[libx264 @ 0000022e7fa621c0] non-strictly-monotonic PTS
[libx264 @ 0000022e7fa621c0] non-strictly-monotonic PTS
[libx264 @ 0000022e7fa621c0] non-strictly-monotonic PTS
[libx264 @ 0000022e7fa621c0] non-strictly-monotonic PTS
[libx264 @ 0000022e7fa621c0] non-strictly-monotonic PTS
[libx264 @ 0000022e7fa621c0] non-strictly-monotonic PTS
[libx264 @ 0000022e7fa621c0] non-strictly-monotonic PTS
[libx264 @ 0000022e7fa621c0] invalid DTS: PTS is less than DTS
[mp4 @ 0000022e090b2300] pts (592) < dts (1129348497) in stream 0
Error: Could not write packet to output file


Any ideas ?
Thanks.


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