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• ffmpeg - Understand images to video output, players show different images and lengths

  8 juillet 2023, par Matt C

  I'm using multiple images to create a video with each image on a 1-second long frame. This is the command I'm using :

  


   ffmpeg -framerate 1 -i 'image%d.jpg' -c:v libx264 -r 1 -pix_fmt yuv420p out.mp4


  


  This seems straightforward and exactly what many others have done with success. However, the output I get is an mp4 which windows file explorer says is 4 seconds long, and is different in VLC and Windows media player and neither is the desired output.

  


  In Windows : the video plays for 4 seconds with a black screen and at this point the time line at the bottom is filled up at 4 seconds, indicating the video is over. But it keeps playing, for another 4 seconds. And the last 4 seconds (from 0:04 to 0:07) is actually the desired output.

  


  





  


  


  


  


  



  


  


  


  


  


  


  


  


  


  


  


  


  


  


  


  


  


  


  


  


  


  


  


  


  


  


  


  


  


  


  


  


  Frame	Image
  1	black screen
  2	black screen
  3	black screen
  4	black screen
  5	image1.jpg
  6	image2.jpg
  7	image3.jpg
  8	image4.jpg

  


  


  In VLC : the video shows last image supplied as input for 3 seconds, followed by the second to last image for 1 second.

  


  





  


  


  


  


  



  


  


  


  


  


  


  


  


  


  


  


  


  


  


  


  


  Frame	Image
  1	image4.jpg
  2	image4.jpg
  3	image4.jpg
  4	image3.jpg

  


  


  Questions :

  


  

  1. How/Why are these different in different players ?

  


  2. Why, in VLC, are only two images showing up, and why would one of them last for 3 seconds ?

  


  3. In Windows, why/how is the video 8 seconds long but shows up as 4 seconds both in the file explorer and in the actual media player ?

  


  4. How do I get the desired output, and what caused my case to not work as it did for seemingly most others ?

  


  


• FFMPEG : i need audio channels 7 & 8 to be the main audio track for a video

  10 avril 2013, par lo_fye

  I have a video with 8 channels of audio.

  I need tracks 7 (Left Stereo) and 8 (Right Stereo) to be the audio for the video (which I'm converting to flv).

  I've tried playing with -filter_complex and the join, amix, and amerge filters, as well as the -map parameter, but I can't seem to find the right combination of values :-/

  Output :

  /usr/local/bin/ffmpeg-1.0/bin/ffmpeg -i '/folder/video_name.mov' -f 'flv' \
  
  -s '320x240' -b '250k' -aspect '4:3' -ac 1 -ab '64k' -ar '22050' -y \
  
  /folder/video_name.flv
  
  
  
  ffmpeg version N-46241-g09ea482 Copyright (c) 2000-2012 the FFmpeg developers
  
    built on Nov  5 2012 07:33:09 with gcc 4.1.2 (GCC) 20080704 (Red Hat 4.1.2-46)
  
    configuration: --prefix=/usr/local/bin/ffmpeg-1.0
  
    libavutil      52.  1.100 / 52.  1.100
  
    libavcodec     54. 70.100 / 54. 70.100
  
    libavformat    54. 35.100 / 54. 35.100
  
    libavdevice    54.  3.100 / 54.  3.100
  
    libavfilter     3. 21.105 /  3. 21.105
  
    libswscale      2.  1.101 /  2.  1.101
  
    libswresample   0. 16.100 /  0. 16.100
  
  Guessed Channel Layout for  Input Stream #0.1 : mono
  
  Guessed Channel Layout for  Input Stream #0.2 : mono
  
  Guessed Channel Layout for  Input Stream #0.3 : mono
  
  Guessed Channel Layout for  Input Stream #0.4 : mono
  
  Guessed Channel Layout for  Input Stream #0.5 : mono
  
  Guessed Channel Layout for  Input Stream #0.6 : mono
  
  Guessed Channel Layout for  Input Stream #0.7 : mono
  
  Guessed Channel Layout for  Input Stream #0.8 : mono
  
  Guessed Channel Layout for  Input Stream #0.9 : mono
  
  Guessed Channel Layout for  Input Stream #0.10 : mono
  
  Input #0, mov,mp4,m4a,3gp,3g2,mj2, from '/folder/video_name.mov':
  
    Metadata:
  
      major_brand     : qt
  
      minor_version   : 537199360
  
      compatible_brands: qt
  
      creation_time   : 2013-04-03 19:45:26
  
    Duration: 00:00:39.03, start: 0.000000, bitrate: 122149 kb/s
  
      Stream #0:0(eng): Video: prores (apch / 0x68637061), yuv422p10le, 1920x1080, 110585 kb/s, SAR 1:1 DAR 16:9, 23.98 fps, 23.98 tbr, 23976 tbn, 23976 tbc
  
      Metadata:
  
        creation_time   : 2013-04-03 19:45:26
  
        handler_name    : Apple Alias Data Handler
  
        timecode        : 00:59:53:00
  
      Stream #0:1(eng): Audio: pcm_s24le (in24 / 0x34326E69), 48000 Hz, mono, s32, 1152 kb/s
  
      Metadata:
  
        creation_time   : 2013-04-03 19:45:26
  
        handler_name    : Apple Alias Data Handler
  
      Stream #0:2(eng): Audio: pcm_s24le (in24 / 0x34326E69), 48000 Hz, mono, s32, 1152 kb/s
  
      Metadata:
  
        creation_time   : 2013-04-03 19:45:26
  
        handler_name    : Apple Alias Data Handler
  
      Stream #0:3(eng): Audio: pcm_s24le (in24 / 0x34326E69), 48000 Hz, mono, s32, 1152 kb/s
  
      Metadata:
  
        creation_time   : 2013-04-03 19:45:26
  
        handler_name    : Apple Alias Data Handler
  
      Stream #0:4(eng): Audio: pcm_s24le (in24 / 0x34326E69), 48000 Hz, mono, s32, 1152 kb/s
  
      Metadata:
  
        creation_time   : 2013-04-03 19:45:26
  
        handler_name    : Apple Alias Data Handler
  
      Stream #0:5(eng): Audio: pcm_s24le (in24 / 0x34326E69), 48000 Hz, mono, s32, 1152 kb/s
  
      Metadata:
  
        creation_time   : 2013-04-03 19:45:26
  
        handler_name    : Apple Alias Data Handler
  
      Stream #0:6(eng): Audio: pcm_s24le (in24 / 0x34326E69), 48000 Hz, mono, s32, 1152 kb/s
  
      Metadata:
  
        creation_time   : 2013-04-03 19:45:26
  
        handler_name    : Apple Alias Data Handler
  
      Stream #0:7(eng): Audio: pcm_s24le (in24 / 0x34326E69), 48000 Hz, mono, s32, 1152 kb/s
  
      Metadata:
  
        creation_time   : 2013-04-03 19:45:26
  
        handler_name    : Apple Alias Data Handler
  
      Stream #0:8(eng): Audio: pcm_s24le (in24 / 0x34326E69), 48000 Hz, mono, s32, 1152 kb/s
  
      Metadata:
  
        creation_time   : 2013-04-03 19:45:26
  
        handler_name    : Apple Alias Data Handler
  
      Stream #0:9(eng): Audio: pcm_s24le (in24 / 0x34326E69), 48000 Hz, mono, s32, 1152 kb/s
  
      Metadata:
  
        creation_time   : 2013-04-03 19:45:26
  
        handler_name    : Apple Alias Data Handler
  
      Stream #0:10(eng): Audio: pcm_s24le (in24 / 0x34326E69), 48000 Hz, mono, s32, 1152 kb/s
  
      Metadata:
  
        creation_time   : 2013-04-03 19:45:26
  
        handler_name    : Apple Alias Data Handler
  
      Stream #0:11(eng): Data: none (tmcd / 0x64636D74)
  
      Metadata:
  
        creation_time   : 2013-04-03 19:45:30
  
        handler_name    : Apple Alias Data Handler
  
        timecode        : 00:59:53:00
  
  Please use -b:a or -b:v, -b is ambiguous
  
  Output #0, flv, to '/folder/video_name.flv':
  
    Metadata:
  
      major_brand     : qt
  
      minor_version   : 537199360
  
      compatible_brands: qt
  
      encoder         : Lavf54.35.100
  
      Stream #0:0(eng): Video: flv1 ([2][0][0][0] / 0x0002), yuv420p, 320x240 [SAR 1:1 DAR 4:3], q=2-31, 250 kb/s, 1k tbn, 23.98 tbc
  
      Metadata:
  
        creation_time   : 2013-04-03 19:45:26
  
        handler_name    : Apple Alias Data Handler
  
        timecode        : 00:59:53:00
  
      Stream #0:1(eng): Audio: adpcm_swf ([1][0][0][0] / 0x0001), 22050 Hz, mono, s16, 88 kb/s
  
      Metadata:
  
        creation_time   : 2013-04-03 19:45:26
  
        handler_name    : Apple Alias Data Handler
  
  Stream mapping:
  
    Stream #0:0 -> #0:0 (prores -> flv)
  
    Stream #0:1 -> #0:1 (pcm_s24le -> adpcm_swf)
  
  Press [q] to stop, [?] for help
  
  frame=   33 fps=0.0 q=2.0 size=     108kB time=00:00:01.99 bitrate= 442.4kbits/s    
  
  frame=   66 fps= 65 q=2.0 size=     225kB time=00:00:02.97 bitrate= 619.0kbits/s    
  
  frame=   99 fps= 65 q=2.0 size=     341kB time=00:00:04.96 bitrate= 561.8kbits/s    
  
  frame=  136 fps= 67 q=2.0 size=     400kB time=00:00:05.99 bitrate= 547.5kbits/s    
  
  frame=  177 fps= 70 q=3.0 size=     482kB time=00:00:07.98 bitrate= 494.3kbits/s    
  
  frame=  210 fps= 69 q=3.7 size=     590kB time=00:00:08.96 bitrate= 539.7kbits/s    
  
  frame=  240 fps= 68 q=6.3 size=     660kB time=00:00:10.01 bitrate= 539.7kbits/s    
  
  frame=  264 fps= 65 q=6.7 size=     719kB time=00:00:11.01 bitrate= 535.2kbits/s    
  
  frame=  288 fps= 63 q=8.4 size=     772kB time=00:00:12.02 bitrate= 526.1kbits/s    
  
  frame=  312 fps= 62 q=15.4 size=     829kB time=00:00:13.65 bitrate= 497.4kbits/s    
  
  frame=  336 fps= 60 q=10.4 size=     875kB time=00:00:14.02 bitrate= 511.1kbits/s    
  
  frame=  360 fps= 59 q=10.6 size=     916kB time=00:00:15.01 bitrate= 499.9kbits/s    
  
  frame=  383 fps= 58 q=17.8 size=     957kB time=00:00:15.97 bitrate= 490.6kbits/s    
  
  frame=  411 fps= 58 q=6.5 size=    1008kB time=00:00:17.97 bitrate= 459.3kbits/s    
  
  frame=  437 fps= 57 q=9.7 size=    1046kB time=00:00:18.99 bitrate= 451.3kbits/s    
  
  frame=  460 fps= 57 q=7.7 size=    1086kB time=00:00:20.01 bitrate= 444.6kbits/s    
  
  frame=  489 fps= 57 q=11.3 size=    1144kB time=00:00:20.99 bitrate= 446.3kbits/s    
  
  frame=  512 fps= 56 q=10.3 size=    1182kB time=00:00:22.01 bitrate= 439.8kbits/s    
  
  frame=  535 fps= 55 q=21.5 size=    1225kB time=00:00:22.98 bitrate= 436.7kbits/s    
  
  frame=  564 fps= 55 q=18.3 size=    1280kB time=00:00:24.00 bitrate= 436.8kbits/s    
  
  frame=  587 fps= 55 q=8.5 size=    1311kB time=00:00:24.98 bitrate= 429.7kbits/s    
  
  frame=  610 fps= 54 q=11.9 size=    1349kB time=00:00:26.00 bitrate= 424.9kbits/s    
  
  frame=  636 fps= 54 q=7.5 size=    1383kB time=00:00:26.98 bitrate= 419.8kbits/s    
  
  frame=  659 fps= 54 q=9.6 size=    1421kB time=00:00:28.00 bitrate= 415.6kbits/s    
  
  frame=  683 fps= 54 q=20.0 size=    1471kB time=00:00:29.02 bitrate= 415.1kbits/s    
  
  frame=  711 fps= 54 q=6.4 size=    1518kB time=00:00:30.00 bitrate= 414.5kbits/s    
  
  frame=  742 fps= 54 q=6.2 size=    1558kB time=00:00:31.02 bitrate= 411.5kbits/s    
  
  frame=  774 fps= 54 q=2.5 size=    1601kB time=00:00:33.01 bitrate= 397.1kbits/s    
  
  frame=  816 fps= 55 q=2.0 size=    1632kB time=00:00:34.50 bitrate= 387.6kbits/s    
  
  frame=  861 fps= 56 q=2.0 size=    1670kB time=00:00:35.99 bitrate= 380.1kbits/s    
  
  frame=  905 fps= 57 q=2.0 size=    1706kB time=00:00:38.03 bitrate= 367.4kbits/s    
  
  frame=  936 fps= 58 q=2.0 Lsize=    1730kB time=00:00:39.05 bitrate= 362.8kbits/s
  
  video:1278kB audio:423kB subtitle:0 global headers:0kB muxing overhead 1.654557%

• FFMpeg Coding in C : Encoder returns EOF at first interaction. Encoder not opened correctly ? [closed]

  26 février, par Davidhohey

  as I'm fairly new to FFMpeg Programming and C in general, the code looks like a mess.

  


  I have smashed my head against a wall trying to get this code to work for about a week.

  


  int decode_encode_pipeline(AVFormatContext *Input_Format_Context, AVFormatContext *Output_Format_Context, int *streams_list){

    const AVCodec *DECodec, *ENCodec;
    AVCodecContext *DECodecContext = NULL, *ENCodecContext = NULL;
    AVCodecParameters *CodecParameters = NULL;
    AVDictionary *opts = NULL;
    AVPacket *Packet;
    AVFrame *Frame;
    int check;

    Packet = av_packet_alloc();
    if(!Packet){
    
        printf("\nFehler bei Allocating Packet");
    
        return 0;
    
    }

    Frame = av_frame_alloc();
    if(!Frame){
    
        printf("\nFehler bei Allocating Frame");
    
        return 0;
    
    }

    CodecParameters = Input_Format_Context->streams[Packet->stream_index]->codecpar;
    if(!CodecParameters){

        printf("\nCodecParameters konnte nicht erstellt oder zugewiesen werden.");

    }

    DECodec = avcodec_find_decoder(CodecParameters->codec_id);
    if(!DECodec){
    
        printf("\nCodec nicht gefunden");
    
        return 0;
    
    }

    DECodecContext = avcodec_alloc_context3(DECodec);
    if (!DECodecContext){
    
        printf("\nFehler bei Allocating CodecContext");
    
        return 0;
    
    }

    ENCodec = avcodec_find_encoder(CodecParameters->codec_id);
    if(!DECodec){
    
        printf("\nCodec nicht gefunden");
    
        return 0;
    
    }

    ENCodecContext = avcodec_alloc_context3(ENCodec);
    if (!ENCodecContext){
    
        printf("\nFehler bei Allocating CodecContext");
    
        return 0;
    
    }

    check = avformat_write_header(Output_Format_Context, &opts);
    if(check < 0){

        printf("\nFehler beim Öffnen des Output Files.");
        
        return 1;

    }

    avcodec_parameters_to_context(DECodecContext, CodecParameters);
    avcodec_parameters_to_context(ENCodecContext, CodecParameters);

    ENCodecContext->width = DECodecContext->width;
    ENCodecContext->height = DECodecContext->height;
    ENCodecContext->bit_rate = DECodecContext->bit_rate;
    ENCodecContext->time_base = (AVRational){1, 30};
    ENCodecContext->framerate = DECodecContext->framerate;
    ENCodecContext->gop_size = DECodecContext->gop_size;
    ENCodecContext->max_b_frames = DECodecContext->max_b_frames;
    ENCodecContext->pix_fmt = DECodecContext->pix_fmt;
    if(ENCodec->id == AV_CODEC_ID_H264){

        av_opt_set(ENCodecContext->priv_data, "preset", "slow", 0);

    }

    check = avcodec_open2(DECodecContext, DECodec, NULL);
    if(check < 0){
    
        printf("\nFehler bei Öffnen von DECodec");
    
        return 1;
    
    }

    check = avcodec_open2(ENCodecContext, ENCodec, NULL);
    if(check < 0){
    
        printf("\nFehler bei Öffnen von ENCodec");
    
        return 1;
    
    }

    while(1){
    
        check = av_read_frame(Input_Format_Context, Packet);
        if(check < 0){
        
            break;
        
        }

        AVStream *in_stream, *out_stream;

        in_stream  = Input_Format_Context->streams[Packet->stream_index];
        out_stream = Output_Format_Context->streams[Packet->stream_index];

        if(in_stream->codecpar->codec_type == AVMEDIA_TYPE_VIDEO && Packet->stream_index == streams_list[Packet->stream_index]){

            check = avcodec_send_packet(DECodecContext, Packet);
            if(check < 0){

                printf("\nFehler bei Encoding");

                return 1;

            }

            AVPacket *EncodedPacket;
            EncodedPacket = av_packet_alloc();
            if(!EncodedPacket){
        
                printf("\nFehler bei Allocating Packet");
        
                return 1;
        
            }

            /*While Loop Decoding*/
            while(check >= 0){
    
                check = avcodec_receive_frame(DECodecContext, Frame);
                if(check == AVERROR(EAGAIN)){
        
                    continue;
        
                }else if(check == AVERROR_EOF){
                    
                    break;
                    
                }else if(check < 0){
        
                    printf("\nFehler bei Decoding");
        
                    return 1;
        
                }

                /*Convert Colorspace*/
                struct SwsContext *SwsContexttoRGB = sws_getContext(Frame->width, Frame->height, Frame->format, Frame->width, Frame->height, AV_PIX_FMT_RGB24, SWS_BILINEAR, NULL, NULL, NULL);
                struct SwsContext *SwsContexttoOriginal = sws_getContext(Frame->width, Frame->height, AV_PIX_FMT_RGB24, Frame->width, Frame->height, Frame->format, SWS_BILINEAR, NULL, NULL, NULL);
                if(!SwsContexttoRGB || !SwsContexttoOriginal){

                    printf("\nSwsContext konnte nicht befüllt werden.");

                    return 1;

                }   

                if(Frame->linesize < 0){

                    printf("\nFehler: linesize ist negativ und nicht kompatibel\n");

                    return 1;

                }

                AVFrame *RGBFrame;
                RGBFrame = av_frame_alloc();
                if(!RGBFrame){

                    printf("\nFehler bei der Reservierung für den RGBFrame");

                    return 1;

                }
                /*
                int number_bytes = av_image_get_buffer_size(AV_PIX_FMT_RGB24, Frame->width, Frame->height, 1);
                if(number_bytes < 0){

                    printf("\nFehler bei der Berechnung der benoetigten Bytes fuer Konvertierung");

                    return 1;

                }
                
                uint8_t *rgb_buffer = (uint8_t *)av_malloc(number_bytes*sizeof(uint8_t));
                if(rgb_buffer == NULL){

                    printf("\nFehler bei der Reservierung für den RGBBuffer");

                    return 1;

                }

                check = av_image_fill_arrays(RGBFrame->data, RGBFrame->linesize, rgb_buffer, AV_PIX_FMT_RGB24, Frame->width, Frame->height, 1);
                if(check < 0){

                    printf("\nFehler bei der Zuweisung der RGB Daten");

                    return 1;

                }*/

                //sws_scale(SwsContexttoRGB, (const uint8_t * const *)Frame->data, Frame->linesize, 0, Frame->height, RGBFrame->data, RGBFrame->linesize);
                sws_scale_frame(SwsContexttoRGB, Frame, RGBFrame);
                printf("\nIch habe die Daten zu RGB konvertiert.");

                //sws_scale(SwsContexttoOriginal, (const uint8_t * const *)RGBFrame->data, RGBFrame->linesize, 0, Frame->height, Frame->data, Frame->linesize);
                sws_scale_frame(SwsContexttoOriginal, RGBFrame, Frame);
                printf("\nIch habe die Daten zurück ins Original konvertiert.");

                Frame->format = ENCodecContext->pix_fmt;
                Frame->width  = ENCodecContext->width;
                Frame->height = ENCodecContext->height;
                
                check = av_frame_get_buffer(Frame, 0);
                if(check < 0){
        
                    printf("\nFehler bei Allocating Frame Buffer");
        
                    return 1;
        
                }

                /* Encoding */
                check = av_frame_make_writable(Frame);
                if(check < 0){

                    printf("\nFehler bei Make Frame Writable");

                    return 1;

                }

                encode(ENCodecContext, Frame, EncodedPacket, Output_Format_Context);

                sws_freeContext(SwsContexttoRGB);
                sws_freeContext(SwsContexttoOriginal);
                av_frame_free(&RGBFrame);
                //av_free(rgb_buffer);

            }

            /* Flushing Encoder */
            encode(ENCodecContext, NULL, EncodedPacket, Output_Format_Context);

            //avcodec_flush_buffers(DECodecContext);
            //avcodec_flush_buffers(ENCodecContext);

            av_packet_free(&EncodedPacket);

        }else{

            av_interleaved_write_frame(Output_Format_Context, Packet);

        }

    }

    av_write_trailer(Output_Format_Context); 

    /* Memory Free */
    avcodec_free_context(&DECodecContext);
    avcodec_free_context(&ENCodecContext);
    avcodec_parameters_free(&CodecParameters);
    av_frame_free(&Frame);
    av_packet_free(&Packet);

    return 0;

}



  


  The function encode looks as follows :

  


  static void encode(AVCodecContext *ENCodecContext, AVFrame *Frame, AVPacket *EncodedPacket, AVFormatContext *Output_Format_Context){

    int check;



    check = avcodec_send_frame(ENCodecContext, Frame);
    if(check == AVERROR(EAGAIN)){
        printf("\nEAGAIN");
    } 
    if(check == AVERROR_EOF){
        printf("\nEOF");
    }
    if(check == AVERROR(EINVAL)){
        printf("\nEINVAL");
    }
    if(check == AVERROR(ENOMEM)){
        printf("\nENOMEM");
    }
    if(check < 0){

        printf("\nFehler bei Encoding Send Frame. Check = %d", check);

        return;

    }

    while(check >= 0){

        check = avcodec_receive_packet(ENCodecContext, EncodedPacket);
        if(check == AVERROR(EAGAIN) || check == AVERROR_EOF){

            return;

        }else if(check < 0){

            printf("\nFehler bei Encoding");

            return;

        }

        if (av_interleaved_write_frame(Output_Format_Context, EncodedPacket) < 0) {

            printf("\nFehler beim Muxen des Paketes.");
            break;

        }

        av_packet_unref(EncodedPacket);

    }

    return;

}


  


  The program should decode a video into the individual frames convert them to RGB24, so I can work with the raw data of the frame, then convert it back to the original format and encode the frames.

  


  The encoder doesn't play nice, as I get an EOF error at avcodec_send_frame().
But I couldn't figure it out why the encoder behaves like this.
And yes I have read the docs and example files, but either I'm massivly missing a crucial detail or I'm just ****.

  


  Any and all help will be and is massivly appreciated.

  


  PS. : The used libraries are libavutil, libavformat, libavcodec, libswscale. All installed with the "-dev" suffix through linux commandline. Should all be the version 7.0 libraries.

  


  Thanks in advance.
With best regards.

  


  

  • Read the docs

  


  • Shifting the encoding step out of the decoding while loop