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• lavc/vvc : Ensure subpictures don't overlap

  22 février, par Frank Plowman

  lavc/vvc : Ensure subpictures don't overlap
  This is essentially a re-implementation of
  
  https://patchwork.ffmpeg.org/project/ffmpeg/patch/20241005223955.54158-1-post@frankplowman.com/
  That patch was not applied last time.  Instead we opted to identify
  
  issues which could be caused by invalid subpicture layouts and remedy
  
  those issues where they manifest, either through error detection or code
  
  hardening.  This was primarily implemented in the set
  
  https://patchwork.ffmpeg.org/project/ffmpeg/list/?series=13381.
  This has worked to some degree, however issues with subpicture layouts
  
  continue to crop up from the fuzzer and I've fixed a number of bugs
  
  related to subpicture layouts since then.  I think it's best to return
  
  to the initial plan and simply check if the subpicture layout is valid
  
  initially.
  This implementation is also lighter than the first time — by doing a
  
  bit more logic in pps_subpic_less_than_one_tile_slice, we are able to
  
  store a tile_in_subpic map rather than a ctu_in_subpic map.  This
  
  reduces the size of the map to the point it becomes possible to allocate
  
  it on the stack.  Similar to 8bd66a8c9587af61c7b46558be3c4ee317c1af5a,
  
  the layout is also validated in the slice map construction code, rather
  
  than in the CBS, which avoids duplicating some logic.
  Signed-off-by : Frank Plowman <post@frankplowman.com>
  

  • [DH] libavcodec/vvc/ps.c

• swscale/lut3d : add 3DLUT dispatch system

  29 novembre 2024, par Niklas Haas

  swscale/lut3d : add 3DLUT dispatch system
  This is a lightweight wrapper around the underlying color management system,
  
  whose job it is merely to manage the 3DLUT state and apply them to the frame
  
  data. This is where we might add platform-specific optimizations in the future.
  I also plan on adding support for more pixel formats in the future. In
  
  particular, we could support YUV or XYZ input formats directly using only
  
  negligible additional code in the 3DLUT setup functions. This would eliminate
  
  the major source of slowdown, which is currently the roundtrip to RGBA64.
  

  • [DH] libswscale/Makefile
  • [DH] libswscale/lut3d.c
  • [DH] libswscale/lut3d.h

• Cannot display a decoded video frame on Raylib

  20 décembre 2024, par gabriel_tiso

  I'm trying to explore libav and raylib just to understand how audio and video work, and also to learn how to build nice interfaces using the raylib project. I've implemented a simple struct capable of decoding audio and video frames. When a video frame appears, I convert it to the RGBA format, which packs the values into 32bpp. This is the setup :

  


      if (av_image_alloc((uint8_t **)media->dst_frame->data,
                       media->dst_frame->linesize, media->ctxs[0]->width,
                       media->ctxs[0]->height, AV_PIX_FMT_RGBA, 1) < 0) {
        fprintf(stderr, "Failed to setup dest image\n");
        return -1;
    }

    media->sws_ctx = sws_getContext(
        media->ctxs[0]->width, media->ctxs[0]->height, media->ctxs[0]->pix_fmt,
        media->ctxs[0]->width, media->ctxs[0]->height, AV_PIX_FMT_RGBA,
        SWS_BILINEAR, NULL, NULL, 0);

    // Later on, in the decode function:
    int ret = sws_scale(media->sws_ctx, media->frame->data,
                            media->frame->linesize, 0, media->frame->height,
                            media->dst_frame->data, media->dst_frame->linesize);



  


  In the main file, I init raylib, and setup the necessary steps to load the texture (here I'm trying to fetch the first video frame in order to show the user a preview of the video, later on I plan to reset the stream to allow a correct playback routine). I think the format of the image is right.

  


      Image previewImage =
        GenImageColor(videoArea.width, videoArea.height, BLACK);
    // I assume this makes the formats compatible
    ImageFormat(&previewImage, PIXELFORMAT_UNCOMPRESSED_R8G8B8A8);

    Texture2D videoTexture = LoadTextureFromImage(previewImage);
    UnloadImage(previewImage);


  


  
        if (!state->has_media) {
            DrawText("Drop a video file here!", videoArea.x + 10,
                     videoArea.y + 10, 20, GRAY);
        } else {
            if (state->first_frame) {
                do {
                    decode_packet(state->media);
                } while (!is_frame_video(state->media));

                UpdateTexture(videoTexture, state->media->dst_frame->data[0]);

                state->first_frame = 0;
            }
        }

        DrawTexture(videoTexture, videoArea.x, videoArea.y, WHITE);


  


  Anyway, this is what I get when a mp4 file is dropped :


  


  It seems like an alignment issue maybe ? Can someone point me in the right direction in order to correctly solve this problem ?