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• When using libva* (ffmpeg) encoded GIF images, an error is reported when compiling the demo

  10 août 2023, par yangjinhui2936

  issuse : I need to use the GIF encoding feature in FFMPEG to encode argb images as gifs.Because the encoding effect of using GIF library is not as good as the effect of FFMPEG.
However, several libraries like avcodec were too bulky, so I did some cropping.I just want to keep the functionality of GIF encoding.
Below is my makefile for cropping ffmpeg :

  


  #!/bin/sh
# ./configure --prefix=$(pwd)/output --arch=arm --target-os=linux --enable-cross-compile --disable-asm --cross-prefix=arm-linux-gnueabihf- 
./configure --prefix=$(pwd)/output --target-os=linux --disable-asm \
--disable-gpl --enable-nonfree --enable-error-resilience --enable-debug --enable-shared --enable-small --enable-zlib \
--disable-ffmpeg --disable-ffprobe --disable-ffplay --disable-programs --disable-symver\
 --disable-doc --disable-htmlpages --disable-manpages --disable-podpages --disable-decoder=h264 --enable-avformat \
 --disable-txtpages --enable-avcodec --enable-avutil \
 --disable-avresample --disable-avfilter --disable-avdevice --disable-postproc \
 --disable-swscale --enable-decoder=gif --enable-demuxer=gif --enable-muxer=gif --disable-iconv \
 --disable-v4l2-m2m --disable-indevs --disable-outdevs

make clean
make -j8

make install


  


  Then link the compiled so to the gif demo.
Blew is gif demo code(He was automatically generated by chatgpt, and I want to verify it) :

  


  #include 
// #include "output/include/imgutils.h"
#include "libavcodec/avcodec.h"
#include "libavformat/avformat.h"
#include "libavutil/avutil.h"

int main() {
    AVCodec *enc_codec;
    AVCodecContext *enc_ctx = NULL;
    AVStream *stream = NULL;
    int ret;

    AVFormatContext *fmt_ctx = avformat_alloc_context();
    if (!fmt_ctx) {
        fprintf(stderr, "Could not allocate format context\n");
        return 1;
    }
    
    AVInputFormat *input_fmt = av_find_input_format("image2");
    if ((ret = avformat_open_input(&fmt_ctx, "input.bmp", input_fmt, NULL)) < 0) {
        fprintf(stderr, "Could not open input file %d\n", ret);
        return ret;
    }

    AVCodec *dec_codec = avcodec_find_decoder(AV_CODEC_ID_BMP);
    if (!dec_codec) {
        fprintf(stderr, "Decoder not found\n");
        return 1;
    }
    
    AVCodecContext *dec_ctx = avcodec_alloc_context3(dec_codec);
    if (!dec_ctx) {
        fprintf(stderr, "Could not allocate decoder context\n");
        return 1;
    }

    if ((ret = avcodec_open2(dec_ctx, dec_codec, NULL)) < 0) {
        fprintf(stderr, "Could not open decoder\n");
        return 1;
    }

    AVOutputFormat *out_fmt = av_guess_format("gif", NULL, NULL);
    if (!out_fmt) {
        fprintf(stderr, "Could not find output format\n");
        return 1;
    }

    AVFormatContext *out_ctx = NULL;
    if ((ret = avformat_alloc_output_context2(&out_ctx, out_fmt, NULL, NULL)) < 0) {
        fprintf(stderr, "Could not allocate output context\n");
        return 1;
    }

    stream = avformat_new_stream(out_ctx, NULL);
    if (!stream) {
        fprintf(stderr, "Could not create new stream\n");
        return 1;
    }

    enc_codec = avcodec_find_encoder(AV_CODEC_ID_GIF);
    if (!enc_codec) {
        fprintf(stderr, "Encoder not found\n");
        return 1;
    }

    enc_ctx = avcodec_alloc_context3(enc_codec);
    if (!enc_ctx) {
        fprintf(stderr, "Could not allocate encoder context\n");
        return 1;
    }

    if ((ret = avcodec_parameters_from_context(stream->codecpar, dec_ctx)) < 0) {
        fprintf(stderr, "Could not copy decoder parameters\n");
        return 1;
    }

    if ((ret = avcodec_open2(enc_ctx, enc_codec, NULL)) < 0) {
        fprintf(stderr, "Could not open encoder\n");
        return 1;
    }
    
    enc_ctx->pix_fmt = AV_PIX_FMT_RGB8; 
    enc_ctx->width = dec_ctx->width; 
    enc_ctx->height = dec_ctx->height; 
    enc_ctx->time_base = (AVRational){1, 25}; 

    avformat_init_output(out_ctx, NULL);

    if (!(out_fmt->flags & AVFMT_NOFILE)) {
        if ((ret = avio_open(&out_ctx->pb, "output.gif", AVIO_FLAG_WRITE)) < 0) {
            fprintf(stderr, "Could not open output file\n");
            return ret;
        }
    }

    avformat_write_header(out_ctx, NULL);

    AVFrame *frame = av_frame_alloc();
    AVPacket pkt;
    int frame_count = 0;

    while (av_read_frame(fmt_ctx, &pkt) >= 0) {
        avcodec_send_packet(dec_ctx, &pkt);
        while (avcodec_receive_frame(dec_ctx, frame) == 0) {
            avcodec_send_frame(enc_ctx, frame);
            while (avcodec_receive_packet(enc_ctx, &pkt) == 0) {
                pkt.stream_index = stream->index;
                av_interleaved_write_frame(out_ctx, &pkt);
                av_packet_unref(&pkt);
            }

            frame_count++;
            printf("Encoded frame %d\n", frame_count);
        }
        av_packet_unref(&pkt);
    }

    av_write_trailer(out_ctx);

    avcodec_close(enc_ctx);
    avcodec_free_context(&enc_ctx);
    avcodec_close(dec_ctx);
    avcodec_free_context(&dec_ctx);
    av_frame_free(&frame);

    avformat_close_input(&fmt_ctx);
    avformat_free_context(fmt_ctx);
    avio_close(out_ctx->pb);
    avformat_free_context(out_ctx);

    return 0;
}



  


  Belw is shell of compile script for gif :

  


  #!/bin/sh
gcc -o x2gif x2gif.c -L ./output/lib/ -l:libavformat.a -l:libavcodec.a -l:libavutil.a -lz -I ./output/include/


  


  Unfortunately, the compilation did not pass.
How can I troubleshoot and resolve this issue ?

  


  ./output/lib/libavutil.a(lfg.o): In function `av_bmg_get':
/data1/yang/tool/ffmpeg-3.4.4/libavutil/lfg.c:59: undefined reference to `log'
./output/lib/libavutil.a(hwcontext_cuda.o): In function `cuda_free_functions':
/data1/yang/tool/ffmpeg-3.4.4/./compat/cuda/dynlink_loader.h:175: undefined reference to `dlclose'
./output/lib/libavutil.a(hwcontext_cuda.o): In function `cuda_load_functions':
/data1/yang/tool/ffmpeg-3.4.4/./compat/cuda/dynlink_loader.h:192: undefined reference to `dlopen'
/data1/yang/tool/ffmpeg-3.4.4/./compat/cuda/dynlink_loader.h:194: undefined reference to `dlsym'
/data1/yang/tool/ffmpeg-3.4.4/./compat/cuda/dynlink_loader.h:195: undefined reference to `dlsym'
/data1/yang/tool/ffmpeg-3.4.4/./compat/cuda/dynlink_loader.h:196: undefined reference to `dlsym'
/data1/yang/tool/ffmpeg-3.4.4/./compat/cuda/dynlink_loader.h:197: undefined reference to `dlsym'
/data1/yang/tool/ffmpeg-3.4.4/./compat/cuda/dynlink_loader.h:198: undefined reference to `dlsym'
./output/lib/libavutil.a(hwcontext_cuda.o):/data1/yang/tool/ffmpeg-3.4.4/./compat/cuda/dynlink_loader.h:199: more undefined references to `dlsym' follow
./output/lib/libavutil.a(rational.o): In function `av_d2q':
/data1/yang/tool/ffmpeg-3.4.4/libavutil/rational.c:120: undefined reference to `floor'
./output/lib/libavutil.a(eval.o): In function `eval_expr':
/data1/yang/tool/ffmpeg-3.4.4/libavutil/eval.c:184: undefined reference to `exp'
/data1/yang/tool/ffmpeg-3.4.4/libavutil/eval.c:185: undefined reference to `exp'
/data1/yang/tool/ffmpeg-3.4.4/libavutil/eval.c:189: undefined reference to `floor'
/data1/yang/tool/ffmpeg-3.4.4/libavutil/eval.c:190: undefined reference to `ceil'
/data1/yang/tool/ffmpeg-3.4.4/libavutil/eval.c:191: undefined reference to `trunc'
/data1/yang/tool/ffmpeg-3.4.4/libavutil/eval.c:192: undefined reference to `round'
/data1/yang/tool/ffmpeg-3.4.4/libavutil/eval.c:263: undefined reference to `pow'
/data1/yang/tool/ffmpeg-3.4.4/libavutil/eval.c:300: undefined reference to `floor'
/data1/yang/tool/ffmpeg-3.4.4/libavutil/eval.c:309: undefined reference to `pow'
/data1/yang/tool/ffmpeg-3.4.4/libavutil/eval.c:315: undefined reference to `hypot'
/data1/yang/tool/ffmpeg-3.4.4/libavutil/eval.c:316: undefined reference to `atan2'
./output/lib/libavutil.a(eval.o): In function `ff_exp10':
/data1/yang/tool/ffmpeg-3.4.4/libavutil/ffmath.h:44: undefined reference to `exp2'
./output/lib/libavutil.a(eval.o): In function `parse_primary':
/data1/yang/tool/ffmpeg-3.4.4/libavutil/eval.c:417: undefined reference to `sinh'
/data1/yang/tool/ffmpeg-3.4.4/libavutil/eval.c:418: undefined reference to `cosh'
/data1/yang/tool/ffmpeg-3.4.4/libavutil/eval.c:419: undefined reference to `tanh'
/data1/yang/tool/ffmpeg-3.4.4/libavutil/eval.c:420: undefined reference to `sin'
/data1/yang/tool/ffmpeg-3.4.4/libavutil/eval.c:421: undefined reference to `cos'
/data1/yang/tool/ffmpeg-3.4.4/libavutil/eval.c:422: undefined reference to `tan'
/data1/yang/tool/ffmpeg-3.4.4/libavutil/eval.c:423: undefined reference to `atan'
/data1/yang/tool/ffmpeg-3.4.4/libavutil/eval.c:424: undefined reference to `asin'
/data1/yang/tool/ffmpeg-3.4.4/libavutil/eval.c:425: undefined reference to `acos'
/data1/yang/tool/ffmpeg-3.4.4/libavutil/eval.c:426: undefined reference to `exp'
/data1/yang/tool/ffmpeg-3.4.4/libavutil/eval.c:427: undefined reference to `log'
/data1/yang/tool/ffmpeg-3.4.4/libavutil/eval.c:428: undefined reference to `fabs'


  


• How To Write An Oscilloscope

  29 avril 2012, par Multimedia Mike — General, gme, oscilloscope, visualization

  I’m trying to figure out how to write a software oscilloscope audio visualization. It’s made more frustrating by the knowledge that I am certain that I have accomplished this task before.

  In this context, the oscilloscope is used to draw the time-domain samples of an audio wave form. I have written such a plugin as part of the xine project. However, for that project, I didn’t have to write the full playback pipeline— my plugin was just handed some PCM data and drew some graphical data in response. Now I’m trying to write the entire engine in a standalone program and I’m wondering how to get it just right.

  
  
  

  This is an SDL-based oscilloscope visualizer and audio player for Game Music Emu library. My approach is to have an audio buffer that holds a second of audio (44100 stereo 16-bit samples). The player updates the visualization at 30 frames per second. The o-scope is 512 pixels wide. So, at every 1/30th second interval, the player dips into the audio buffer at position ((frame_number % 30) * 44100 / 30) and takes the first 512 stereo frames for plotting on the graph.

  It seems to be working okay, I guess. The only problem is that the A/V sync seems to be slightly misaligned. I am just wondering if this is the correct approach. Perhaps the player should be performing some slightly more complicated calculation over those (44100/30) audio frames during each update in order to obtain a more accurate graph ? I described my process to an electrical engineer friend of mine and he insisted that I needed to apply something called hysteresis to the output or I would never get accurate A/V sync in this scenario.

  Further, I know that some schools of thought on these matters require that the dots in those graphs be connected, that the scattered points simply won’t do. I guess it’s a stylistic choice.

  Still, I think I have a reasonable, workable approach here. I might just be starting the visualization 1/30th of a second too late.

• ffmpeg segments only the first part of my audio file

  30 juin 2012, par hammat

  I'm implementing a http live streaming server to send audio file to iOS devices.
  No problem with Apple's tools, mediafilesegmenter, my files are valid and it works fine.

  I'm trying now to segment the same file using ffmpeg. I've downloaded the last stable version which is the 0.10.2 for now.

  Here is how I try to segment my mp3 file :

  ./ffmpeg -re -i input.mp3 -f segment -segment_time 10 -segment_list outputList.m3u8 -acodec libmp3lame -map 0 output%03d.mp3

  It starts the mapping like expected but finish with only one .mp3 file.

  Did I miss something in the process ?
  Thanks in advance.

  edit

  Ok here is my latest command line :

  ffmpeg -i input.mp3 -c:a libmp3lame -b:a 128k -map 0:0 -f segment -segment_time 10 -segment_list outputlist.m3u8 -segment_format mp3 'output%03d.mp3'

  It still gives me only one file but the file is the hole song, not only one part.
  Here is the output of ffmpeg :

  ffmpeg version 0.10.2 Copyright (c) 2000-2012 the FFmpeg developers 
  
  built on Apr 20 2012 07:08:29 with gcc 4.5.2   
  
  configuration: --enable-gpl --enable-version3 --enable-nonfree --enable-postproc --enable-libmp3lame   
  
      libavutil      51. 35.100 / 51. 35.100   
  
      libavcodec     53. 61.100 / 53. 61.100   
  
      libavformat    53. 32.100 /
  
          53. 32.100   
  
      libavdevice    53.  4.100 / 53.  4.100   
  
      libavfilter     2. 61.100 /  2. 61.100   
  
      libswscale      2.  1.100 /  2.  1.100   
  
      libswresample   0.  6.100 /  0.  6.100   
  
      libpostproc    52.  0.100 /  52.  0.100 
  
      [mp3 @ 0x8e4f120] max_analyze_duration 5000000 reached at 5015510
  
  Input #0, mp3, from 'BeachHouse-Myth.mp3':   
  
      Metadata:
  
              title           : Myth
  
              artist          : Beach House
  
              track           : /
  
              album           : Bloom
  
              disc            : /
  
              genre           : Alternative
  
              TSRC            : USSUB1296501   
  
      Duration: 00:04:18.69, start: 0.000000, bitrate: 320 kb/s
  
              Stream #0:0: Audio: mp3, 44100 Hz, stereo, s16, 320 kb/s Output #0, segment, to 'stream%03d.mp3':   Metadata:
  
              title           : Myth
  
              artist          : Beach House
  
              track           : /
  
              album           : Bloom
  
              disc            : /
  
              genre           : Alternative
  
              TSRC            : USSUB1296501
  
              encoder         : Lavf53.32.100
  
              Stream #0:0: Audio: mp3, 44100 Hz, stereo, s16, 128 kb/s
  
  Stream mapping:   
  
      Stream #0:0 -> #0:0 (mp3 -> libmp3lame) 
  
      Press [q] to stop, [?] for help 
  
      Truncating packet of size 1024 to 105ate=   0.0kbits/s    
  
      Truncating packet of size 1024 to 1 
  
      size=       0kB time=00:04:18.71 bitrate=   0.0kbits/s     video:0kB audio:4042kB global headers:0kB muxing overhead -100.000000%