/*

  * This file is part of FFmpeg.

  *

  * FFmpeg is free software; you can redistribute it and/or

  * modify it under the terms of the GNU Lesser General Public
  * License as published by the Free Software Foundation; either
  * version 2.1 of the License, or (at your option) any later version.
  *

  * FFmpeg is distributed in the hope that it will be useful,

  * but WITHOUT ANY WARRANTY; without even the implied warranty of
  * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
  * Lesser General Public License for more details.
  *
  * You should have received a copy of the GNU Lesser General Public

  * License along with FFmpeg; if not, write to the Free Software

  * Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA
  */
 
 #include "libavutil/buffer.h"
 #include "libavutil/hwcontext.h"
 #include "libavutil/log.h"
 #include "libavutil/opt.h"
 #include "libavutil/pixdesc.h"
 
 #include "avfilter.h"
 #include "formats.h"
 #include "internal.h"
 #include "video.h"
 
 typedef struct HWMapContext {
     const AVClass *class;
 
     AVBufferRef   *hwframes_ref;
 
     int            mode;

     char          *derive_device_type;

     int            reverse;

 } HWMapContext;
 
 static int hwmap_query_formats(AVFilterContext *avctx)
 {

     int ret;
 
     if ((ret = ff_formats_ref(ff_all_formats(AVMEDIA_TYPE_VIDEO),
                               &avctx->inputs[0]->out_formats)) < 0 ||
         (ret = ff_formats_ref(ff_all_formats(AVMEDIA_TYPE_VIDEO),
                               &avctx->outputs[0]->in_formats)) < 0)
         return ret;
 

     return 0;
 }
 
 static int hwmap_config_output(AVFilterLink *outlink)
 {
     AVFilterContext *avctx = outlink->src;
     HWMapContext      *ctx = avctx->priv;
     AVFilterLink   *inlink = avctx->inputs[0];
     AVHWFramesContext *hwfc;

     AVBufferRef *device;

     const AVPixFmtDescriptor *desc;

     int err, device_is_derived;

 
     av_log(avctx, AV_LOG_DEBUG, "Configure hwmap %s -> %s.\n",
            av_get_pix_fmt_name(inlink->format),
            av_get_pix_fmt_name(outlink->format));
 

     av_buffer_unref(&ctx->hwframes_ref);
 
     device = avctx->hw_device_ctx;

     device_is_derived = 0;

     if (inlink->hw_frames_ctx) {
         hwfc = (AVHWFramesContext*)inlink->hw_frames_ctx->data;
 

         if (ctx->derive_device_type) {
             enum AVHWDeviceType type;
 
             type = av_hwdevice_find_type_by_name(ctx->derive_device_type);
             if (type == AV_HWDEVICE_TYPE_NONE) {
                 av_log(avctx, AV_LOG_ERROR, "Invalid device type.\n");

                 err = AVERROR(EINVAL);

                 goto fail;
             }
 
             err = av_hwdevice_ctx_create_derived(&device, type,
                                                  hwfc->device_ref, 0);
             if (err < 0) {
                 av_log(avctx, AV_LOG_ERROR, "Failed to created derived "
                        "device context: %d.\n", err);
                 goto fail;
             }

             device_is_derived = 1;

         }
 

         desc = av_pix_fmt_desc_get(outlink->format);

         if (!desc) {
             err = AVERROR(EINVAL);
             goto fail;
         }

 
         if (inlink->format == hwfc->format &&

             (desc->flags & AV_PIX_FMT_FLAG_HWACCEL) &&
             !ctx->reverse) {

             // Map between two hardware formats (including the case of
             // undoing an existing mapping).
 

             if (!device) {
                 av_log(avctx, AV_LOG_ERROR, "A device reference is "
                        "required to map to a hardware format.\n");
                 err = AVERROR(EINVAL);

                 goto fail;
             }
 
             err = av_hwframe_ctx_create_derived(&ctx->hwframes_ref,
                                                 outlink->format,

                                                 device,

                                                 inlink->hw_frames_ctx,
                                                 ctx->mode);

             if (err < 0) {
                 av_log(avctx, AV_LOG_ERROR, "Failed to create derived "
                        "frames context: %d.\n", err);

                 goto fail;

             }

         } else if (inlink->format == hwfc->format &&
                    (desc->flags & AV_PIX_FMT_FLAG_HWACCEL) &&
                    ctx->reverse) {
             // Map between two hardware formats, but do it in reverse.
             // Make a new hwframe context for the target type, and then
             // overwrite the input hwframe context with a derived context
             // mapped from that back to the source type.
             AVBufferRef *source;
             AVHWFramesContext *frames;
 
             ctx->hwframes_ref = av_hwframe_ctx_alloc(device);
             if (!ctx->hwframes_ref) {
                 err = AVERROR(ENOMEM);
                 goto fail;
             }
             frames = (AVHWFramesContext*)ctx->hwframes_ref->data;
 
             frames->format    = outlink->format;
             frames->sw_format = hwfc->sw_format;
             frames->width     = hwfc->width;
             frames->height    = hwfc->height;

 
             if (avctx->extra_hw_frames >= 0)
                 frames->initial_pool_size = 2 + avctx->extra_hw_frames;

 
             err = av_hwframe_ctx_init(ctx->hwframes_ref);
             if (err < 0) {
                 av_log(avctx, AV_LOG_ERROR, "Failed to initialise "
                        "target frames context: %d.\n", err);
                 goto fail;
             }
 
             err = av_hwframe_ctx_create_derived(&source,
                                                 inlink->format,
                                                 hwfc->device_ref,
                                                 ctx->hwframes_ref,
                                                 ctx->mode);
             if (err < 0) {
                 av_log(avctx, AV_LOG_ERROR, "Failed to create "
                        "derived source frames context: %d.\n", err);
                 goto fail;
             }
 
             // Here is the naughty bit.  This overwriting changes what
             // ff_get_video_buffer() in the previous filter returns -
             // it will now give a frame allocated here mapped back to
             // the format it expects.  If there were any additional
             // constraints on the output frames there then this may
             // break nastily.
             av_buffer_unref(&inlink->hw_frames_ctx);
             inlink->hw_frames_ctx = source;
 

         } else if ((outlink->format == hwfc->format &&
                     inlink->format  == hwfc->sw_format) ||
                    inlink->format == hwfc->format) {
             // Map from a hardware format to a software format, or
             // undo an existing such mapping.
 
             ctx->hwframes_ref = av_buffer_ref(inlink->hw_frames_ctx);
             if (!ctx->hwframes_ref) {
                 err = AVERROR(ENOMEM);
                 goto fail;
             }
 
         } else {
             // Non-matching formats - not supported.
 
             av_log(avctx, AV_LOG_ERROR, "Unsupported formats for "
                    "hwmap: from %s (%s) to %s.\n",
                    av_get_pix_fmt_name(inlink->format),
                    av_get_pix_fmt_name(hwfc->format),
                    av_get_pix_fmt_name(outlink->format));
             err = AVERROR(EINVAL);
             goto fail;
         }
     } else if (avctx->hw_device_ctx) {
         // Map from a software format to a hardware format.  This
         // creates a new hwframe context like hwupload, but then
         // returns frames mapped from that to the previous link in
         // order to fill them without an additional copy.
 

         if (!device) {
             av_log(avctx, AV_LOG_ERROR, "A device reference is "

                    "required to create new frames with reverse "

                    "mapping.\n");
             err = AVERROR(EINVAL);

             goto fail;
         }
 

         ctx->reverse = 1;

 
         ctx->hwframes_ref = av_hwframe_ctx_alloc(device);

         if (!ctx->hwframes_ref) {
             err = AVERROR(ENOMEM);
             goto fail;
         }
         hwfc = (AVHWFramesContext*)ctx->hwframes_ref->data;
 
         hwfc->format    = outlink->format;
         hwfc->sw_format = inlink->format;
         hwfc->width     = inlink->w;
         hwfc->height    = inlink->h;
 

         if (avctx->extra_hw_frames >= 0)
             hwfc->initial_pool_size = 2 + avctx->extra_hw_frames;
 

         err = av_hwframe_ctx_init(ctx->hwframes_ref);
         if (err < 0) {
             av_log(avctx, AV_LOG_ERROR, "Failed to create frame "

                    "context for reverse mapping: %d.\n", err);

             goto fail;
         }
 
     } else {
         av_log(avctx, AV_LOG_ERROR, "Mapping requires a hardware "
                "context (a device, or frames on input).\n");
         return AVERROR(EINVAL);
     }
 
     outlink->hw_frames_ctx = av_buffer_ref(ctx->hwframes_ref);
     if (!outlink->hw_frames_ctx) {
         err = AVERROR(ENOMEM);
         goto fail;
     }
 
     outlink->w = inlink->w;
     outlink->h = inlink->h;
 

     if (device_is_derived)
         av_buffer_unref(&device);

     return 0;
 
 fail:

     if (device_is_derived)
         av_buffer_unref(&device);

     av_buffer_unref(&ctx->hwframes_ref);
     return err;
 }
 
 static AVFrame *hwmap_get_buffer(AVFilterLink *inlink, int w, int h)
 {
     AVFilterContext *avctx = inlink->dst;
     AVFilterLink  *outlink = avctx->outputs[0];
     HWMapContext      *ctx = avctx->priv;
 

     if (ctx->reverse && !inlink->hw_frames_ctx) {

         AVFrame *src, *dst;
         int err;
 
         src = ff_get_video_buffer(outlink, w, h);
         if (!src) {
             av_log(avctx, AV_LOG_ERROR, "Failed to allocate source "
                    "frame for software mapping.\n");
             return NULL;
         }
 
         dst = av_frame_alloc();
         if (!dst) {
             av_frame_free(&src);
             return NULL;
         }
 
         err = av_hwframe_map(dst, src, ctx->mode);
         if (err) {
             av_log(avctx, AV_LOG_ERROR, "Failed to map frame to "
                    "software: %d.\n", err);
             av_frame_free(&src);
             av_frame_free(&dst);
             return NULL;
         }
 
         av_frame_free(&src);
         return dst;
     } else {
         return ff_default_get_video_buffer(inlink, w, h);
     }
 }
 
 static int hwmap_filter_frame(AVFilterLink *link, AVFrame *input)
 {
     AVFilterContext *avctx = link->dst;
     AVFilterLink  *outlink = avctx->outputs[0];
     HWMapContext      *ctx = avctx->priv;
     AVFrame *map = NULL;
     int err;
 
     av_log(ctx, AV_LOG_DEBUG, "Filter input: %s, %ux%u (%"PRId64").\n",
            av_get_pix_fmt_name(input->format),
            input->width, input->height, input->pts);
 
     map = av_frame_alloc();
     if (!map) {
         err = AVERROR(ENOMEM);
         goto fail;
     }
 
     map->format = outlink->format;
     map->hw_frames_ctx = av_buffer_ref(ctx->hwframes_ref);
     if (!map->hw_frames_ctx) {
         err = AVERROR(ENOMEM);
         goto fail;
     }
 

     if (ctx->reverse && !input->hw_frames_ctx) {

         // If we mapped backwards from hardware to software, we need
         // to attach the hardware frame context to the input frame to
         // make the mapping visible to av_hwframe_map().
         input->hw_frames_ctx = av_buffer_ref(ctx->hwframes_ref);
         if (!input->hw_frames_ctx) {
             err = AVERROR(ENOMEM);
             goto fail;
         }
     }
 
     err = av_hwframe_map(map, input, ctx->mode);
     if (err < 0) {
         av_log(avctx, AV_LOG_ERROR, "Failed to map frame: %d.\n", err);
         goto fail;
     }
 
     err = av_frame_copy_props(map, input);
     if (err < 0)
         goto fail;
 
     av_frame_free(&input);
 
     av_log(ctx, AV_LOG_DEBUG, "Filter output: %s, %ux%u (%"PRId64").\n",
            av_get_pix_fmt_name(map->format),
            map->width, map->height, map->pts);
 
     return ff_filter_frame(outlink, map);
 
 fail:
     av_frame_free(&input);
     av_frame_free(&map);
     return err;
 }
 
 static av_cold void hwmap_uninit(AVFilterContext *avctx)
 {
     HWMapContext *ctx = avctx->priv;
 
     av_buffer_unref(&ctx->hwframes_ref);
 }
 
 #define OFFSET(x) offsetof(HWMapContext, x)

 #define FLAGS (AV_OPT_FLAG_FILTERING_PARAM|AV_OPT_FLAG_VIDEO_PARAM)

 static const AVOption hwmap_options[] = {
     { "mode", "Frame mapping mode",
       OFFSET(mode), AV_OPT_TYPE_FLAGS,
       { .i64 = AV_HWFRAME_MAP_READ | AV_HWFRAME_MAP_WRITE },
       0, INT_MAX, FLAGS, "mode" },
 
     { "read", "Mapping should be readable",
       0, AV_OPT_TYPE_CONST, { .i64 = AV_HWFRAME_MAP_READ },
       INT_MIN, INT_MAX, FLAGS, "mode" },
     { "write", "Mapping should be writeable",
       0, AV_OPT_TYPE_CONST, { .i64 = AV_HWFRAME_MAP_WRITE },
       INT_MIN, INT_MAX, FLAGS, "mode" },
     { "overwrite", "Mapping will always overwrite the entire frame",
       0, AV_OPT_TYPE_CONST, { .i64 = AV_HWFRAME_MAP_OVERWRITE },
       INT_MIN, INT_MAX, FLAGS, "mode" },
     { "direct", "Mapping should not involve any copying",
       0, AV_OPT_TYPE_CONST, { .i64 = AV_HWFRAME_MAP_DIRECT },
       INT_MIN, INT_MAX, FLAGS, "mode" },
 

     { "derive_device", "Derive a new device of this type",
       OFFSET(derive_device_type), AV_OPT_TYPE_STRING,
       { .str = NULL }, 0, 0, FLAGS },

     { "reverse", "Map in reverse (create and allocate in the sink)",
       OFFSET(reverse), AV_OPT_TYPE_INT,
       { .i64 = 0 }, 0, 1, FLAGS },

     { NULL }

 };
 

 AVFILTER_DEFINE_CLASS(hwmap);

 
 static const AVFilterPad hwmap_inputs[] = {
     {
         .name             = "default",
         .type             = AVMEDIA_TYPE_VIDEO,

         .get_video_buffer = hwmap_get_buffer,
         .filter_frame     = hwmap_filter_frame,

     },
     { NULL }
 };
 
 static const AVFilterPad hwmap_outputs[] = {
     {
         .name         = "default",
         .type         = AVMEDIA_TYPE_VIDEO,

         .config_props = hwmap_config_output,

     },
     { NULL }
 };
 
 AVFilter ff_vf_hwmap = {
     .name           = "hwmap",
     .description    = NULL_IF_CONFIG_SMALL("Map hardware frames"),

     .uninit         = hwmap_uninit,

     .priv_size      = sizeof(HWMapContext),
     .priv_class     = &hwmap_class,

     .query_formats  = hwmap_query_formats,

     .inputs         = hwmap_inputs,
     .outputs        = hwmap_outputs,
     .flags_internal = FF_FILTER_FLAG_HWFRAME_AWARE,
 };