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• FFMPEG / MJPEG Encoding / How to add DQT table in packet data ?

  20 mai 2020, par GoodSimon

  I write my own transcoder in C++ to convert any image to jpeg based on the examples in ffmpeg sources. I use the MJPEG codec to create a jpeg image. By sending AVFrame to the MJPEG encoder I get AVPacket. Then I just take the data from the packet->data structure with the size avpacket->size and save it to a file with the jpg extension.
The problem is that the finished JPEG image has only one DQT (Define Quantization Table). As far as I understand, there should be two tables in the file.

  



  What do I need to do to have 2 quantization tables in avpacket->data ?

  


• How to save h264 frames as jpeg images using ffmpeg ?

  17 août 2020, par Matthew Czarnek

  I would like to save thumbnails from a h264 stream that I'm turning into ffmpeg avpackets as jpegs.

  


  I'm started with a h264 AVPacket (iframe) and decode it into an AVFrame using avcodec_send_packet/avcodec_receive_frame. Now trying to go from AVFrame and convert into AVPacket using avcodec_send_frame/avcodec_receive_packet

  


  I can convert to png instead jpg, though I do get a the video looking like it's outputting three separate frames squeezed side by side into one. Wondering if it's one frame is R, next G, and finally B. I'm not sure, clearly I'm doing something wrong there. I figured it's possible it's the png encoder and I don't need it, so let's get jpg working first. But jpg is outputting unopenable files.

  


  Any advice ?

  


  Here is my code :

  


  int output_thumbnails(AVPacket* video_packet)
{
    char png_file_name[max_chars_per_filename];
    char thumbnail_id_char[10];
    _itoa_s(thumbnail_id, thumbnail_id_char, 10);
    strcpy_s(png_file_name, max_chars_per_filename, time_stamped_filepath);
    strcat_s(png_file_name, max_chars_per_filename, time_stamped_filename);
    strcat_s(png_file_name, max_chars_per_filename, thumbnail_id_char);
    strcat_s(png_file_name, max_chars_per_filename, ".jpg");
    thumbnail_id++;

    int error_code = send_AVPacket_to_videocard(video_packet, av_codec_context_RTSP);

    //if (error_code == AVERROR_EOF)
    //{
    //  //  error_code = videocard_to_PNG(png_file_name, av_codec_context_RTSP, av_codec_RTSP);
    //}
    if (error_code == AVERROR(EAGAIN)) //send packets to videocard until function returns EAGAIN
    {
        error_code = videocard_to_PNG(png_file_name, av_codec_context_RTSP);

        //EAGAIN means that the video card buffer is ready to have the png pulled off of it
        if (error_code == AVERROR_EOF)
        {
            //  error_code = videocard_to_PNG(png_file_name, av_codec_context_RTSP, av_codec_RTSP);
        }
        else if (error_code == AVERROR(EAGAIN))
        {

        }
        else
        {
            deal_with_av_errors(error_code, __LINE__, __FILE__);
        }
    }
    else
    {
        deal_with_av_errors(error_code, __LINE__, __FILE__);
    }
    
    return 0;
}


  


  VideoThumbnailGenerator.h :
#include "VideoThumbnailGenerator.h"

  


  bool decoder_context_created = false;
bool encoder_context_created = false;

AVCodecContext* h264_decoder_codec_ctx;
AVCodecContext* thumbnail_encoder_codec_ctx;

int send_AVPacket_to_videocard(AVPacket* packet, AVCodecContext* codec_ctx)
{
    if(!decoder_context_created)
    {
        AVCodec* h264_codec = avcodec_find_decoder(codec_ctx->codec_id);
        h264_decoder_codec_ctx = avcodec_alloc_context3(h264_codec);

        h264_decoder_codec_ctx->width = codec_ctx->width;
        h264_decoder_codec_ctx->height = codec_ctx->height;
        h264_decoder_codec_ctx->pix_fmt = AV_PIX_FMT_RGB24;
        h264_decoder_codec_ctx->codec_type = AVMEDIA_TYPE_VIDEO;
        h264_decoder_codec_ctx->skip_frame = AVDISCARD_NONINTRA;//AVDISCARD_NONREF;//AVDISCARD_NONINTRA;
        
        h264_decoder_codec_ctx->time_base.num = 1;
        h264_decoder_codec_ctx->time_base.den = 30;

        h264_decoder_codec_ctx->extradata = codec_ctx->extradata;
        h264_decoder_codec_ctx->extradata_size = codec_ctx->extradata_size;
        
        int error_code = avcodec_open2(h264_decoder_codec_ctx, h264_codec, NULL);
        if (!h264_codec) {
            return -1;
        }

        if (error_code < 0)
        {
            return error_code;
        }
        decoder_context_created = true;
    }

    
    //use hardware decoding to decode video frame
    int error_code = avcodec_send_packet(h264_decoder_codec_ctx, packet);
    if(error_code == AVERROR(EAGAIN))
    {
        return AVERROR(EAGAIN);
    }
    if(error_code<0)
    {
        printf("Error: Could not send packet to video card");
        return error_code;
    }

    return 0;
}

int videocard_to_PNG(char *png_file_path, AVCodecContext* codec_ctx)
{
    if (!encoder_context_created)
    {
        //AVCodec* thumbnail_codec = avcodec_find_encoder(AV_CODEC_ID_PNG);
        AVCodec* thumbnail_codec = avcodec_find_encoder(AV_CODEC_ID_JPEG2000);
        thumbnail_encoder_codec_ctx = avcodec_alloc_context3(thumbnail_codec);

        thumbnail_encoder_codec_ctx->width = 128;
        thumbnail_encoder_codec_ctx->height = (int)(((float)codec_ctx->height/(float)codec_ctx->width) * 128);
        thumbnail_encoder_codec_ctx->pix_fmt = AV_PIX_FMT_RGB24; //AV_PIX_FMT_YUVJ420P
        thumbnail_encoder_codec_ctx->codec_type = AVMEDIA_TYPE_VIDEO;

        thumbnail_encoder_codec_ctx->time_base.num = 1;
        thumbnail_encoder_codec_ctx->time_base.den = 30;

        bool thread_check = thumbnail_encoder_codec_ctx->thread_type & FF_THREAD_FRAME;
        bool frame_threads_check = thumbnail_encoder_codec_ctx->codec->capabilities & AV_CODEC_CAP_FRAME_THREADS;
        
        int error_code = avcodec_open2(thumbnail_encoder_codec_ctx, thumbnail_codec, NULL);
        if (!thumbnail_codec) {
            return -1;
        }

        if (error_code < 0)
        {
            return error_code;
        }
        encoder_context_created = true;
    }
    
    AVFrame* thumbnail_frame = av_frame_alloc();
    AVPacket* thumbnail_packet = av_packet_alloc();
    //av_init_packet(png_packet);
    int error_code = avcodec_receive_frame(h264_decoder_codec_ctx, thumbnail_frame);

    //check for errors everytime
    //note EAGAIN errors won't get here since they won't get past while
    if (error_code < 0 && error_code != AVERROR(EAGAIN))
    {
        printf("Error: Could not get frame from video card");
        return error_code;
    }
    //empty buffer if there are any more frames to pull (there shouldn't be)
    //while(error_code != AVERROR(EAGAIN))
    //{
    //  //check for errors everytime
    //  //note EAGAIN errors won't get here since they won't get past while
    //  if (error_code < 0)
    //  {
    //      printf("Error: Could not get frame from video card");
    //      return error_code;
    //  }
    //  
    //  error_code = avcodec_receive_frame(h264_decoder_codec_ctx, png_frame);
    //}

    //now we convert back to AVPacket, this time one holding PNG info, so we can store to file
    error_code = avcodec_send_frame(thumbnail_encoder_codec_ctx, thumbnail_frame);

    if (error_code >= 0) {
        error_code = avcodec_receive_packet(thumbnail_encoder_codec_ctx, thumbnail_packet);

        FILE* out_PNG;

        errno_t err = fopen_s(&out_PNG, png_file_path, "wb");
        if (err == 0) {
            fwrite(thumbnail_packet->data, thumbnail_packet->size, 1, out_PNG);
        }
        fclose(out_PNG);

    }
    return error_code;
}


  


• How to Convert video into mp3 format using ffmpeg in nodejs and angular and then save converted audio into the database

  2 septembre 2021, par Amir Shahzad

  This is nodejs server side file

  


  const express = require('express');
const ffmpeg  = require('fluent-ffmpeg');
const fileUpload = require('express-fileupload');
const mongoose = require('mongoose');
const cors   = require('cors')
const app = express();
const Video = require('./models/video');
mongoose.connect('mongodb://localhost:27017/YoutubeApp', {
    useNewUrlParser: true,
    useUnifiedTopology: true,
});
const db = mongoose.connection;
db.on('error', console.error.bind(console, 'connection error'));
db.once('open', () => {
   console.log('Data Base Connected Successfully!');
});

app.use(fileUpload({
   useTempFiles: true,
   tempFileDir: 'temp/'
}));
app.use(express.json());
app.use(express.urlencoded({ extended: true }));
app.use(cors({ origin: 'http://localhost:4200' }));


ffmpeg.setFfmpegPath('/usr/bin/ffmpeg');

app.post('/mp4tomp3', (req, res) => {
  convertdata = req.body;
  console.log('path of innput is', req.body);
  function convert(input, output, callback) {
     ffmpeg(input)
         .output(output)
         .on('end', function() {                    
             console.log('conversion ended');
             callback(null);
           }).on('error', function(err){
              console.log('error: ', err.code, err.msg);
              callback(err);
           }).run();
      }
     convert(convertdata, './temp/output.mp3', function(err){
        if(!err) {
          console.log('conversion complete');

 
     }
 })

 app.listen(3000, () => {
    console.log('Server Start On Port 3000')
 })


  


  In Convert function i not know how i can get input by the user i'm new in angular Please anyone can solve this out thanks in advance

  


  This is video model file

  


  const mongoose = require("mongoose");
const Schema = mongoose.Schema;

const videoSchema = new Schema({
    mp4: String,
});
module.exports = mongoose.model("Videos", videoSchema);


  


  **This is Typescript code in angular client side that handle user input and select video **

  


  import { ThrowStmt } from '@angular/compiler';
import { Component, OnInit } from '@angular/core';
import { FormBuilder, FormGroup, Validators } from '@angular/forms';
import { VideoConversionService } from 'src/services/video-conversion.service';

@Component({
  selector: 'app-root',
  templateUrl: './app.component.html',
  styleUrls: ['./app.component.css']
})
export class AppComponent implements OnInit {

   submitted =false;
   form! : FormGroup
   data:any

   constructor(private formBuilder: FormBuilder,
       private videoService: VideoConversionService){}

   creatForm(){
    this.form = this.formBuilder.group({
    mp4: ['', Validators.required],
  });
  }
   ngOnInit(): void {
   this.creatForm();

  }


  convertVideo(){
    this.submitted = true
    this.videoService.conversion(this.form.value).subscribe(res => {
    this.data = res;
 })
 }

 }


  


  I do not know how to create logic to do that (convert video into audio using angular framework)

  


  This is app.component.html file where i want to get video from the user using input field

  


  <div class="container">&#xA;   <h1>Video Proccessing App</h1>&#xA;   <form>&#xA;     <input type="file" formcontrolname="mp4" />&#xA;     <input type="submit" value="Convert" />&#xA;  </form>&#xA;</div>&#xA;

  


  


  But my code is not working and video is not converting into audio

  


  This is my video service file where i calling nodejs api to perform the task

  


  import { Injectable } from '@angular/core';
import { HttpClient  } from '@angular/common/http';
@Injectable({
   providedIn: 'root'
})
export class VideoConversionService {

constructor(private httpClient: HttpClient) { }

conversion(data: any){
   return this.httpClient.post('http://localhost:3000/mp4tomp3', data)
}
}


  


  Please anyone can solve my problem Thanks in advance