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  • FFMPEG Encoding Issues

    16 octobre 2014, par madprogrammer2015

    I am having issues encoding screen captures, into a h.264 file for viewing. The program below is cobbled together from examples here and here. The first example, uses an older version of the ffmpeg api. So I tried to update that example for use in my program. The file is created and has something written to it, but when I view the file. The encoded images are all distorted. I am able to run the video encoding example from the ffmpeg api successfully. This is my first time posting, so if I missed anything please let me know.

    I appreciate any assistance that is given.

    My program :

    #include
    #include <string>
    #include <sstream>
    #include
    #include <iostream>
    #include

    extern "C"{
    #include
    #include <libavcodec></libavcodec>avcodec.h>
    #include <libavutil></libavutil>imgutils.h>
    #include <libswscale></libswscale>swscale.h>
    #include <libavutil></libavutil>opt.h>
    }

    using namespace std;

    void ScreenShot(const char* BmpName, uint8_t *frame)
    {
       HWND DesktopHwnd = GetDesktopWindow();
       RECT DesktopParams;
       HDC DevC = GetDC(DesktopHwnd);
       GetWindowRect(DesktopHwnd,&amp;DesktopParams);
       DWORD Width = DesktopParams.right - DesktopParams.left;
       DWORD Height = DesktopParams.bottom - DesktopParams.top;

       DWORD FileSize = sizeof(BITMAPFILEHEADER)+sizeof(BITMAPINFOHEADER)+(sizeof(RGBTRIPLE)+1*(Width*Height*4));
       char *BmpFileData = (char*)GlobalAlloc(0x0040,FileSize);

       PBITMAPFILEHEADER BFileHeader = (PBITMAPFILEHEADER)BmpFileData;
       PBITMAPINFOHEADER  BInfoHeader = (PBITMAPINFOHEADER)&amp;BmpFileData[sizeof(BITMAPFILEHEADER)];

       BFileHeader->bfType = 0x4D42; // BM
       BFileHeader->bfSize = sizeof(BITMAPFILEHEADER);
       BFileHeader->bfOffBits = sizeof(BITMAPFILEHEADER)+sizeof(BITMAPINFOHEADER);

       BInfoHeader->biSize = sizeof(BITMAPINFOHEADER);
       BInfoHeader->biPlanes = 1;
       BInfoHeader->biBitCount = 32;
       BInfoHeader->biCompression = BI_RGB;
       BInfoHeader->biHeight = Height;
       BInfoHeader->biWidth = Width;

       RGBTRIPLE *Image = (RGBTRIPLE*)&amp;BmpFileData[sizeof(BITMAPFILEHEADER)+sizeof(BITMAPINFOHEADER)];
       RGBTRIPLE color;
       //pPixels = (RGBQUAD **)new RGBQUAD[sizeof(BITMAPFILEHEADER) + sizeof(BITMAPINFOHEADER)];
       int start = clock();

       HDC CaptureDC = CreateCompatibleDC(DevC);
       HBITMAP CaptureBitmap = CreateCompatibleBitmap(DevC,Width,Height);
       SelectObject(CaptureDC,CaptureBitmap);
       BitBlt(CaptureDC,0,0,Width,Height,DevC,0,0,SRCCOPY|CAPTUREBLT);
       GetDIBits(CaptureDC,CaptureBitmap,0,Height,frame,(LPBITMAPINFO)BInfoHeader, DIB_RGB_COLORS);

       int end = clock();

       cout &lt;&lt; "it took " &lt;&lt; end - start &lt;&lt; " to capture a frame" &lt;&lt; endl;

       DWORD Junk;
       HANDLE FH = CreateFileA(BmpName,GENERIC_WRITE,FILE_SHARE_WRITE,0,CREATE_ALWAYS,0,0);
       WriteFile(FH,BmpFileData,FileSize,&amp;Junk,0);
       CloseHandle(FH);
       GlobalFree(BmpFileData);
    }

    void video_encode_example(const char *filename, int codec_id)
    {
       AVCodec *codec;
       AVCodecContext *c= NULL;
       int i, ret, x, y, got_output;
       FILE *f;
       AVFrame *frame;
       AVPacket pkt;
       uint8_t endcode[] = { 0, 0, 1, 0xb7 };

       printf("Encode video file %s\n", filename);

       /* find the mpeg1 video encoder */
       codec = avcodec_find_encoder(AV_CODEC_ID_H264);
       if (!codec) {
           fprintf(stderr, "Codec not found\n");
           cin.get();
           exit(1);
       }

       c = avcodec_alloc_context3(codec);
       if (!c) {
           fprintf(stderr, "Could not allocate video codec context\n");
           cin.get();
           exit(1);
       }

       /* put sample parameters */
       c->bit_rate = 400000;
       /* resolution must be a multiple of two */
       c->width = 352;
       c->height = 288;
       /* frames per second */
       c->time_base.num=1;
       c->time_base.den = 25;
       c->gop_size = 10; /* emit one intra frame every ten frames */
       c->max_b_frames=1;
       c->pix_fmt = AV_PIX_FMT_YUV420P;

       if(codec_id == AV_CODEC_ID_H264)
           av_opt_set(c->priv_data, "preset", "slow", 0);

       /* open it */
       if (avcodec_open2(c, codec, NULL) &lt; 0) {
           fprintf(stderr, "Could not open codec\n");
           exit(1);
       }

       f = fopen(filename, "wb");
       if (!f) {
           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);
       }

       frame->format = c->pix_fmt;
       frame->width  = c->width;
       frame->height = c->height;

       /* the image can be allocated by any means and av_image_alloc() is
       just the most convenient way if av_malloc() is to be used */
       ret = av_image_alloc(frame->data, frame->linesize, c->width, c->height, c->pix_fmt, 32);

       if (ret &lt; 0) {
           fprintf(stderr, "Could not allocate raw picture buffer\n");
           exit(1);
       }

       /* encode 1 second of video */
       for(i=0;i&lt;250;i++) {
           av_init_packet(&amp;pkt);
           pkt.data = NULL;    // packet data will be allocated by the encoder
           pkt.size = 0;

           fflush(stdout);
           /* prepare a dummy image */
           /* Y */
           for(y=0;yheight;y++) {
               for(x=0;xwidth;x++) {
                   frame->data[0][y * frame->linesize[0] + x] = x + y + i * 3;
               }
           }

           /* Cb and Cr */
           for(y=0;yheight/2;y++) {
               for(x=0;xwidth/2;x++) {
                   frame->data[1][y * frame->linesize[1] + x] = 128 + y + i * 2;
                   frame->data[2][y * frame->linesize[2] + x] = 64 + x + i * 5;
               }
           }

           frame->pts = i;

           /* encode the image */
           ret = avcodec_encode_video2(c, &amp;pkt, frame, &amp;got_output);
           if (ret &lt; 0) {
               fprintf(stderr, "Error encoding frame\n");
               exit(1);
           }

           if (got_output) {
               printf("Write frame %3d (size=%5d)\n", i, pkt.size);
               fwrite(pkt.data, 1, pkt.size, f);
               av_free_packet(&amp;pkt);
           }
       }

       /* get the delayed frames */
       for (got_output = 1; got_output; i++) {
           fflush(stdout);

           ret = avcodec_encode_video2(c, &amp;pkt, NULL, &amp;got_output);

           if (ret &lt; 0) {
               fprintf(stderr, "Error encoding frame\n");
               exit(1);
           }

           if (got_output) {
               printf("Write frame %3d (size=%5d)\n", i, pkt.size);
               fwrite(pkt.data, 1, pkt.size, f);
               av_free_packet(&amp;pkt);
           }
       }

       /* add sequence end code to have a real mpeg file */
       fwrite(endcode, 1, sizeof(endcode), f);
       fclose(f);

        avcodec_close(c);
        av_free(c);
        av_freep(&amp;frame->data[0]);
        av_frame_free(&amp;frame);
        printf("\n");
    }

    void write_video_frame()
    {
    }

    int lineSizeOfFrame(int width)
    {
       return  (width*24 + 31)/32 * 4;//((width*24 / 8) + 3) &amp; ~3;//(width*24 + 31)/32 * 4;
    }

    int getScreenshotWithCursor(uint8_t* frame)
    {
       int successful = 0;
           HDC screen, bitmapDC;
           HBITMAP screen_bitmap;

           screen = GetDC(NULL);
           RECT DesktopParams;

           HWND desktop = GetDesktopWindow();
           GetWindowRect(desktop, &amp;DesktopParams);

           int width = DesktopParams.right;
           int height = DesktopParams.bottom;

           bitmapDC = CreateCompatibleDC(screen);
           screen_bitmap = CreateCompatibleBitmap(screen, width, height);
           SelectObject(bitmapDC, screen_bitmap);
           if (BitBlt(bitmapDC, 0, 0, width, height, screen, 0, 0, SRCCOPY))
           {
                   int pos_x, pos_y;
                   HICON hcur;
                   ICONINFO icon_info;
                   CURSORINFO cursor_info;
                   cursor_info.cbSize = sizeof(CURSORINFO);
                   if (GetCursorInfo(&amp;cursor_info))
                   {
                           if (cursor_info.flags == CURSOR_SHOWING)
                           {
                                   hcur = CopyIcon(cursor_info.hCursor);
                                   if (GetIconInfo(hcur, &amp;icon_info))
                                   {
                                           pos_x = cursor_info.ptScreenPos.x - icon_info.xHotspot;
                                           pos_y = cursor_info.ptScreenPos.y - icon_info.yHotspot;
                                           DrawIcon(bitmapDC, pos_x, pos_y, hcur);
                                           if (icon_info.hbmColor) DeleteObject(icon_info.hbmColor);
                                           if (icon_info.hbmMask) DeleteObject(icon_info.hbmMask);
                                   }
                           }
                   }
                   int header_size = sizeof(BITMAPINFOHEADER) + 256*sizeof(RGBQUAD);
                   size_t line_size = lineSizeOfFrame(width);
                   PBITMAPINFO lpbi = (PBITMAPINFO) malloc(header_size);
                   lpbi->bmiHeader.biSize = header_size;
                   lpbi->bmiHeader.biWidth = width;
                   lpbi->bmiHeader.biHeight = height;
                   lpbi->bmiHeader.biPlanes = 1;
                   lpbi->bmiHeader.biBitCount = 24;
                   lpbi->bmiHeader.biCompression = BI_RGB;
                   lpbi->bmiHeader.biSizeImage = height*line_size;
                   lpbi->bmiHeader.biXPelsPerMeter = 0;
                   lpbi->bmiHeader.biYPelsPerMeter = 0;
                   lpbi->bmiHeader.biClrUsed = 0;
                   lpbi->bmiHeader.biClrImportant = 0;
                   if (GetDIBits(bitmapDC, screen_bitmap, 0, height, (LPVOID)frame, lpbi, DIB_RGB_COLORS))
                   {
                       int i;
                       uint8_t *buf_begin = frame;
                       uint8_t *buf_end = frame + line_size*(lpbi->bmiHeader.biHeight - 1);
                       void *temp = malloc(line_size);
                       for (i = 0; i &lt; lpbi->bmiHeader.biHeight / 2; ++i)
                       {
                           memcpy(temp, buf_begin, line_size);
                           memcpy(buf_begin, buf_end, line_size);
                           memcpy(buf_end, temp, line_size);
                           buf_begin += line_size;
                           buf_end -= line_size;
                       }
                       cout &lt;&lt; *buf_begin &lt;&lt; endl;
                       free(temp);
                       successful = 1;
                   }
                   free(lpbi);
           }
           DeleteObject(screen_bitmap);
           DeleteDC(bitmapDC);
           ReleaseDC(NULL, screen);
           return successful;
    }

    int main()
    {
       RECT DesktopParams;

       HWND desktop = GetDesktopWindow();
       GetWindowRect(desktop, &amp;DesktopParams);

       int width = DesktopParams.right;
       int height = DesktopParams.bottom;
       uint8_t *frame = (uint8_t *)malloc(width * height);

       AVCodec *codec;
       AVCodecContext *codecContext = NULL;
       AVPacket packet;
       FILE *f;
       AVFrame *pictureYUV = NULL;
       AVFrame *pictureRGB;

       avcodec_register_all();

       codec = avcodec_find_encoder(AV_CODEC_ID_H264);

       if(!codec)
       {
           cout &lt;&lt; "codec not found!" &lt;&lt; endl;
           cin.get();
           return 1;
       }
       else
       {
           cout &lt;&lt; "codec h265 found!" &lt;&lt; endl;
       }

       codecContext = avcodec_alloc_context3(codec);

       codecContext->bit_rate = width * height * 4;
       codecContext->width = width;
       codecContext->height = height;
       codecContext->time_base.num = 1;
       codecContext->time_base.den = 250;
       codecContext->gop_size = 10;
       codecContext->max_b_frames = 1;
       codecContext->keyint_min = 1;
       codecContext->i_quant_factor = (float)0.71;                        // qscale factor between P and I frames
       codecContext->b_frame_strategy = 20;                               ///// find out exactly what this does
       codecContext->qcompress = (float)0.6;                              ///// find out exactly what this does
       codecContext->qmin = 20;                                           // minimum quantizer
       codecContext->qmax = 51;                                           // maximum quantizer
       codecContext->max_qdiff = 4;                                       // maximum quantizer difference between frames
       codecContext->refs = 4;                                            // number of reference frames
       codecContext->trellis = 1;
       codecContext->pix_fmt = AV_PIX_FMT_YUV420P;
       codecContext->codec_id = AV_CODEC_ID_H264;
       codecContext->codec_type = AVMEDIA_TYPE_VIDEO;

       if(avcodec_open2(codecContext, codec, NULL) &lt; 0)
       {
           cout &lt;&lt; "couldn't open codec" &lt;&lt; endl;
           cout &lt;&lt; stderr &lt;&lt; endl;
           cin.get();
           return 1;
       }
       else
       {
           cout &lt;&lt; "opened h265 codec!" &lt;&lt; endl;
           cin.get();
       }

       f = fopen("test.h264", "wb");

       if(!f)
       {
           cout &lt;&lt; "Unable to open file" &lt;&lt; endl;
           return 1;
       }



       struct SwsContext *img_convert_ctx = sws_getContext(codecContext->width, codecContext->height, PIX_FMT_RGB32, codecContext->width,
           codecContext->height, codecContext->pix_fmt, SWS_BILINEAR, NULL, NULL, NULL);

       int got_output = 0, i = 0;
       uint8_t encode[] = { 0, 0, 1, 0xb7 };

       try
       {
           for(i = 0; i &lt; codecContext->time_base.den; i++)
           {
               av_init_packet(&amp;packet);
               packet.data = NULL;
               packet.size = 0;

               pictureRGB = av_frame_alloc();
               pictureYUV = av_frame_alloc();

               getScreenshotWithCursor(frame);
               //ScreenShot("example.bmp", frame);

               int nbytes = avpicture_get_size(AV_PIX_FMT_YUV420P, codecContext->width, codecContext->height);                                    // allocating outbuffer
               uint8_t* outbuffer = (uint8_t*)av_malloc(nbytes*sizeof(uint8_t));

               pictureRGB = av_frame_alloc();
               pictureYUV = av_frame_alloc();

               avpicture_fill((AVPicture*)pictureRGB, frame, PIX_FMT_RGB32, codecContext->width, codecContext->height);                   // fill image with input screenshot
               avpicture_fill((AVPicture*)pictureYUV, outbuffer, PIX_FMT_YUV420P, codecContext->width, codecContext->height);
               av_image_alloc(pictureYUV->data, pictureYUV->linesize, codecContext->width, codecContext->height, codecContext->pix_fmt, 32);

               sws_scale(img_convert_ctx, pictureRGB->data, pictureRGB->linesize, 0, codecContext->height, pictureYUV->data, pictureYUV->linesize);

               pictureYUV->pts = i;

               avcodec_encode_video2(codecContext, &amp;packet, pictureYUV, &amp;got_output);

               if(got_output)
               {
                   printf("Write frame %3d (size=%5d)\n", i, packet.size);
                   fwrite(packet.data, 1, packet.size, f);
                   av_free_packet(&amp;packet);
               }

               //av_frame_free(&amp;pictureRGB);
               //av_frame_free(&amp;pictureYUV);
           }

           for(got_output = 1; got_output; i++)
           {
               fflush(stdout);

               avcodec_encode_video2(codecContext, &amp;packet, NULL, &amp;got_output);

               if (got_output) {
                   printf("Write frame %3d (size=%5d)\n", i, packet.size);
                   fwrite(packet.data, 1, packet.size, f);
                   av_free_packet(&amp;packet);
               }
           }
       }
       catch(std::exception ex)
       {
           cout &lt;&lt; ex.what() &lt;&lt; endl;
       }

       avcodec_close(codecContext);
       av_free(codecContext);
       av_freep(&amp;pictureYUV->data[0]);
       //av_frame_free(&amp;picture);
       fwrite(encode, 1, sizeof(encode), f);
       fclose(f);

       cin.get();

       return 0;
    }
    </iostream></sstream></string>
  • Having audio sync issues after concatenating several mp4 with and without sound

    19 décembre 2019, par CYRUS

    I’m posting today because I have a problem when I use ffmpeg. I have a small program that creates mp4 files for me, often with sounds and sometimes without, until now I used ffmpeg to concatenate them.

    But I just realized that if I have an mp4 file that doesn’t contain audio then the whole audio track of the final file goes out of sync. This only happens when I have some mp4 files that don’t have audio. I think it’s also useful to know that the program I’m using gives me a lot of mp4 (>20) and I can’t know in advance which ones have audio or not...

    Here is the code I use, I saw on the forum that the mp4 format was badly managed and that it was better to use ts format for concatenation that’s why I do this

    for f in $(ls *.mp4); do
      ffmpeg -i $f -c copy -bsf:v h264_mp4toannexb -f mpegts $f.ts
    done

    CONCAT=$(echo $(ls *.ts ) | sed -e "s/ /|/g")

    ffmpeg -analyzeduration 2147483647 -probesize 2147483647 -i "concat:$CONCAT" -c copy output.ts
    ffmpeg -analyzeduration 2147483647 -probesize 2147483647 -i output.ts -acodec copy -vcodec copy output.mp4

    I noticed that when the final file goes out of sync this error appears :

    Input #0, mpegts, from 'concat:video0.mp4.ts|video01.mp4.ts|video012.mp4.ts|video0123.mp4.ts|video01234.mp4.ts|video012345.mp4.ts|video0123456.mp4.ts|video01234567.mp4.ts|video012345678.mp4.ts|video0123456789.mp4.ts|video012345678910.mp4.ts|video01234567891011.mp4.ts|video0123456789101112.mp4.ts|video012345678910111213.mp4.ts|video01234567891011121314.mp4.ts|video0123456789101112131415.mp4.ts|video012345678910111213141516.mp4.ts|video01234567891011121314151617.mp4.ts|video0123456789101112131415161718.mp4.ts|video012345678910111213141516171819.mp4.ts|zzzz.mp4.ts':
     Duration: 00:00:05.02, start: 1.420222, bitrate: 63089 kb/s
     Program 1
       Metadata:
         service_name    : Service01
         service_provider: FFmpeg
       Stream #0:0[0x100]: Video: h264 (High) ([27][0][0][0] / 0x001B), yuv420p(tv, bt709, progressive), 640x1136, 30 fps, 240 tbr, 90k tbn, 60 tbc
       Stream #0:1[0x101](und): Audio: aac (LC) ([15][0][0][0] / 0x000F), 44100 Hz, mono, fltp, 145 kb/s
    Output #0, mpegts, to 'output.ts':
     Metadata:
       encoder         : Lavf58.20.100
       Stream #0:0: Video: h264 (High) ([27][0][0][0] / 0x001B), yuv420p(tv, bt709, progressive), 640x1136, q=2-31, 30 fps, 240 tbr, 90k tbn, 90k tbc
       Stream #0:1(und): Audio: aac (LC) ([15][0][0][0] / 0x000F), 44100 Hz, mono, fltp, 145 kb/s
    Stream mapping:
     Stream #0:0 -> #0:0 (copy)
     Stream #0:1 -> #0:1 (copy)
    Press [q] to stop, [?] for help
    [mpegts @ 0x7f9c68800000] DTS 130180 &lt; 573000 out of order &lt;-- HERE
    [mpegts @ 0x7f9c68800000] DTS 130180 &lt; 654000 out of order &lt;-- HERE
    [mpegts @ 0x7f9c68800000] DTS 130180 &lt; 1477180 out of order &lt;-- HERE

    I’ve tried several different combinations of members answer on other topics but nothing worked for me.
    I don’t know if the problem comes from the moment I convert .mp4 files to .ts and I forget to set appropriate codec, or if it comes from the concat command ?

    I’m almost sure that there is a simple way to fix this issue but unfortunately I don’t have enough ffmpeg knowledge.

    Thanks for your help :)

    EDIT 1 :

    I changed the for loop of the programme to :

    for f in $(ls *.mp4); do

       TEST=$(ffprobe -i $f -show_streams -select_streams a -loglevel error)

       if [ "$TEST" ]; then

           ffmpeg -i $f -c copy -bsf:v h264_mp4toannexb -f mpegts $f.ts

       fi

    done

    It only makes the script to ignore the files that don’t have audio, but this way it works, so maybe adding dummy audio to those files could make the job as @Gyan suggested in the comments, but how to do that ?

    EDIT 2 SOLVED

    I found how to add dummy audio on my silent file, that solved my problem this is my final working for loop :

    for f in $(ls *.mp4); do

       TEST=$(ffprobe -i $f -show_streams -select_streams a -loglevel error)

       if [ "$TEST" ]; then

           ffmpeg -i $f -c copy -bsf:v h264_mp4toannexb -f mpegts $f.ts

       else

           ffmpeg -f lavfi -i anullsrc -i $f -shortest -c:v copy -c:a aac -map 0:a -map 1:v $f.a.ts
           ffmpeg -i $f.a.ts -c copy -bsf:v h264_mp4toannexb -f mpegts $f.ts
           rm $f.a.ts

       fi

    done
  • Révision 21710 : Fix #2957 : fonctions helper d’import/export CSV depuis/vers un fichier, issues de

    25 octobre 2014, par cedric -