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• Up-to-date example for libavfilter usage [closed]

  25 juillet 2024, par Michael Werner

  I am looking for an example how to use the latest FFmpeg libavfilter functions to add a bitmap overlay image to a video. I only find more than ten years old examples which are based on an old versions of libavfilter.

  


  What I am trying to do :
On Windows with latest libav (full build) an C++ app reads YUV420P frames from a frame grabber card. I want to draw a Windows bitmap BGR24 overlay image (from file) on every frame via libavfilter. First I convert the BGR24 overlay image via format filter to YUV420P. Then I feed the YUV420P frame from frame grabber and the YUV420P overlay into the overlay filter. Everything seems to be fine but when I try to get the frame out of the filter graph I always get an "Resource is temporary not available" (EAGAIN) error, independent on how many frames I put into the graph.

  


  My current initialization code looks like below. It does not report any errors or warnings but when I try to get the filtered frame out of the graph via av_buffersink_get_frame I always get an EAGAIN return code.

  


  Here is my current initialization code :

  


  int init_overlay_filter(AVFilterGraph** graph, AVFilterContext** src_ctx, AVFilterContext** overlay_src_ctx,
                        AVFilterContext** sink_ctx)
{
    AVFilterGraph* filter_graph;
    AVFilterContext* buffersrc_ctx;
    AVFilterContext* overlay_buffersrc_ctx;
    AVFilterContext* buffersink_ctx;
    AVFilterContext* overlay_ctx;
    AVFilterContext* format_ctx;
    const AVFilter *buffersrc, *buffersink, *overlay_buffersrc, *overlay_filter, *format_filter;
    int ret;

    // Create the filter graph
    filter_graph = avfilter_graph_alloc();
    if (!filter_graph)
    {
        fprintf(stderr, "Unable to create filter graph.\n");
        return AVERROR(ENOMEM);
    }

    // Create buffer source filter for main video
    buffersrc = avfilter_get_by_name("buffer");
    if (!buffersrc)
    {
        fprintf(stderr, "Unable to find buffer filter.\n");
        return AVERROR_FILTER_NOT_FOUND;
    }

    // Create buffer source filter for overlay image
    overlay_buffersrc = avfilter_get_by_name("buffer");
    if (!overlay_buffersrc)
    {
        fprintf(stderr, "Unable to find buffer filter.\n");
        return AVERROR_FILTER_NOT_FOUND;
    }

    // Create buffer sink filter
    buffersink = avfilter_get_by_name("buffersink");
    if (!buffersink)
    {
        fprintf(stderr, "Unable to find buffersink filter.\n");
        return AVERROR_FILTER_NOT_FOUND;
    }

    // Create overlay filter
    overlay_filter = avfilter_get_by_name("overlay");
    if (!overlay_filter)
    {
        fprintf(stderr, "Unable to find overlay filter.\n");
        return AVERROR_FILTER_NOT_FOUND;
    }

    // Create format filter
    format_filter = avfilter_get_by_name("format");
    if (!format_filter) 
    {
        fprintf(stderr, "Unable to find format filter.\n");
        return AVERROR_FILTER_NOT_FOUND;
    }

    // Initialize the main video buffer source
    char args[512];
    snprintf(args, sizeof(args),
             "video_size=1920x1080:pix_fmt=yuv420p:time_base=1/25:pixel_aspect=1/1");
    ret = avfilter_graph_create_filter(&buffersrc_ctx, buffersrc, "in", args, NULL, filter_graph);
    if (ret < 0)
    {
        fprintf(stderr, "Unable to create buffer source filter for main video.\n");
        return ret;
    }

    // Initialize the overlay buffer source
    snprintf(args, sizeof(args),
             "video_size=165x165:pix_fmt=bgr24:time_base=1/25:pixel_aspect=1/1");
    ret = avfilter_graph_create_filter(&overlay_buffersrc_ctx, overlay_buffersrc, "overlay_in", args, NULL,
                                       filter_graph);
    if (ret < 0)
    {
        fprintf(stderr, "Unable to create buffer source filter for overlay.\n");
        return ret;
    }

    // Initialize the format filter to convert overlay image to yuv420p
    snprintf(args, sizeof(args), "pix_fmts=yuv420p");
    ret = avfilter_graph_create_filter(&format_ctx, format_filter, "format", args, NULL, filter_graph);

    if (ret < 0) 
    {
        fprintf(stderr, "Unable to create format filter.\n");
        return ret;
    }

    // Initialize the buffer sink
    ret = avfilter_graph_create_filter(&buffersink_ctx, buffersink, "out", NULL, NULL, filter_graph);
    if (ret < 0)
    {
        fprintf(stderr, "Unable to create buffer sink filter.\n");
        return ret;
    }

    // Initialize the overlay filter
    ret = avfilter_graph_create_filter(&overlay_ctx, overlay_filter, "overlay", "W-w:H-h:enable='between(t,0,20)':format=yuv420", NULL, filter_graph);
    if (ret < 0)
    {
        fprintf(stderr, "Unable to create overlay filter.\n");
        return ret;
    }

    // Connect the filters
    ret = avfilter_link(overlay_buffersrc_ctx, 0, format_ctx, 0);

    if (ret >= 0)
    {
        ret = avfilter_link(buffersrc_ctx, 0, overlay_ctx, 0);
    }
    else
    {
        fprintf(stderr, "Unable to configure filter graph.\n");
        return ret;
    }


    if (ret >= 0) 
    {
        ret = avfilter_link(format_ctx, 0, overlay_ctx, 1);
    }
    else
    {
        fprintf(stderr, "Unable to configure filter graph.\n");
        return ret;
    }

    if (ret >= 0) 
    {
        if ((ret = avfilter_link(overlay_ctx, 0, buffersink_ctx, 0)) < 0)
        {
            fprintf(stderr, "Unable to link filter graph.\n");
            return ret;
        }
    }
    else
    {
        fprintf(stderr, "Unable to configure filter graph.\n");
        return ret;
    }

    // Configure the filter graph
    if ((ret = avfilter_graph_config(filter_graph, NULL)) < 0)
    {
        fprintf(stderr, "Unable to configure filter graph.\n");
        return ret;
    }

    *graph = filter_graph;
    *src_ctx = buffersrc_ctx;
    *overlay_src_ctx = overlay_buffersrc_ctx;
    *sink_ctx = buffersink_ctx;

    return 0;
}


  


• FFMPEG MKV -> MP4 Batch Conversion

  15 juillet 2024, par blaziken386

  I'm trying to write a program that lets me convert a series of .mkv files with subtitle files into .mp4 files with the subs hardcoded.

  


  Right now, the script I use is

  


  ffmpeg -i input.mkv -vf subtitles=input.mkv output.mp4



  


  This is fine, but it means I can only convert them one at a time, and it's kind of a hassle because it means I have to fiddle with it every few minutes to set up the next one.

  


  I have another script I use for converting .flac files to .mp3 files, which is

  


  @ECHO OFF

FOR %%f IN (*.flac) DO (
echo Converting: %%f
ffmpeg -i "%%f" -ab 320k -map_metadata 0 "%%~nf.mp3"
)

echo Finished

PAUSE



  


  Running that converts every single .flac folder into an .mp3 equivalent, with the same filename and everything.

  


  I've tried to combine the above scripts into something like this :

  


  @ECHO OFF

FOR %%f IN (*.mkv) DO (
echo Converting: %%f
ffmpeg -i "%%f" -vf subtitles=%%f "%%~nf.mp4"
)

echo Finished

PAUSE


  


  but every time I do so, it returns errors like "invalid argument" or "unable to find a suitable output type", or "error initializing filters", or "2 frames left in the queue on closing" or something along those lines. I've swapped out subtitles=%%f for "subtitles-%%f" or subtitles="%%f.mkv" and so on and so forth, and none of those give me what I want either. Sometimes it creates Empty .mp4 file containers with nothing in them, sometimes it does nothing at all.

  


  I don't really understand what exactly is happening under the hood in that flac->mp3 code, because I grabbed it from a different stackoverflow post years ago. All I know is that trying to copy that code and repurpose it into something else doesn't work. Is this just an issue where I've fucked up the formatting of the code and not realized it, or is this a "ffmpeg can't actually do that because of a weird technical issue" thing ?

  


  I also tried the code listed here, when Stackoverflow listed that as a possible duplicate, but that gave me similar errors, and I don't really understand why !

  


  Also, if it's relevant, I'm running windows.

  


• avr32 : remove explicit support

  9 juin 2024, par Rémi Denis-Courmont

  avr32 : remove explicit support
  The vendor has long since switched to Arm, with the last product
  
  reaching their official end-of-life over 11 years ago. Linux support for
  
  the ISA was dropped 7 years ago. More importantly, this architecture was
  
  never supported by upstream GCC, and the vendor fork is stuck at version
  
  4.2, which FFmpeg no longer supports (as per C11 requirement).
  Presumably, this is still the case given the lack of vendor support.
  
  Indeed all of the code being removed here consisted of inline assembler
  
  scalar optimisations. A sane C compiler should be able to perform those
  
  automatically nowadays (with the sole exception of fast CLZ detection),
  
  but this is moot as this architecture is evidently dead.
  

  • [DH] configure
  • [DH] libavcodec/avr32/mathops.h
  • [DH] libavcodec/mathops.h
  • [DH] libavutil/avr32/intreadwrite.h
  • [DH] libavutil/intreadwrite.h