[FFmpeg-devel] [crop support for matroska demuxer, V4 2/3] libavcodec: Public code to support container crop

[Dmitrii Ovchinnikov <ovchinnikov.dmitrii@gmail.com>]

From: Dmitrii Ovchinnikov <ovchinnikov.dmitrii@gmail.com>

Support both simple and receive_frame api
The container crop information is applied additional to frame crop information
---
 libavcodec/codec_par.c | 30 ++++++++++++++---------
 libavcodec/decode.c    | 54 ++++++++++++++++++++++++++++++++++++++++++
 2 files changed, 73 insertions(+), 11 deletions(-)

diff --git a/libavcodec/codec_par.c b/libavcodec/codec_par.c
index abda649aa8..9738402434 100644
--- a/libavcodec/codec_par.c
+++ b/libavcodec/codec_par.c
@@ -115,17 +115,21 @@ int avcodec_parameters_from_context(AVCodecParameters *par,
 
     switch (par->codec_type) {
     case AVMEDIA_TYPE_VIDEO:
-        par->format              = codec->pix_fmt;
-        par->width               = codec->width;
-        par->height              = codec->height;
-        par->field_order         = codec->field_order;
-        par->color_range         = codec->color_range;
-        par->color_primaries     = codec->color_primaries;
-        par->color_trc           = codec->color_trc;
-        par->color_space         = codec->colorspace;
-        par->chroma_location     = codec->chroma_sample_location;
-        par->sample_aspect_ratio = codec->sample_aspect_ratio;
-        par->video_delay         = codec->has_b_frames;
+        par->format                = codec->pix_fmt;
+        par->width                 = codec->width;
+        par->height                = codec->height;
+        par->container_crop_top    = codec->container_crop_top;
+        par->container_crop_left   = codec->container_crop_left;
+        par->container_crop_bottom = codec->container_crop_bottom;
+        par->container_crop_right  = codec->container_crop_right;
+        par->field_order           = codec->field_order;
+        par->color_range           = codec->color_range;
+        par->color_primaries       = codec->color_primaries;
+        par->color_trc             = codec->color_trc;
+        par->color_space           = codec->colorspace;
+        par->chroma_location       = codec->chroma_sample_location;
+        par->sample_aspect_ratio   = codec->sample_aspect_ratio;
+        par->video_delay           = codec->has_b_frames;
         break;
     case AVMEDIA_TYPE_AUDIO:
         par->format           = codec->sample_fmt;
@@ -199,6 +203,10 @@ int avcodec_parameters_to_context(AVCodecContext *codec,
         codec->pix_fmt                = par->format;
         codec->width                  = par->width;
         codec->height                 = par->height;
+        codec->container_crop_top     = par->container_crop_top;
+        codec->container_crop_left    = par->container_crop_left;
+        codec->container_crop_bottom  = par->container_crop_bottom;
+        codec->container_crop_right   = par->container_crop_right;
         codec->field_order            = par->field_order;
         codec->color_range            = par->color_range;
         codec->color_primaries        = par->color_primaries;
diff --git a/libavcodec/decode.c b/libavcodec/decode.c
index 6be2d3d6ed..9e44fcb293 100644
--- a/libavcodec/decode.c
+++ b/libavcodec/decode.c
@@ -693,6 +693,60 @@ static int apply_cropping(AVCodecContext *avctx, AVFrame *frame)
     if (!avctx->apply_cropping)
         return 0;
 
+    if (avctx->container_apply_cropping == FF_CONTAINER_CROPPING_ADDITION)
+    {
+        /*check if container parameter and elementary streaming cropping parameters are saft for apploying  */
+        if (avctx->container_crop_left + frame->crop_left >= INT_MAX - (avctx->container_crop_right + frame->crop_right) ||
+            avctx->container_crop_top + frame->crop_top >= INT_MAX - (avctx->container_crop_bottom + frame->crop_bottom) ||
+            (avctx->container_crop_left + frame->crop_left + avctx->container_crop_right + frame->crop_right) >= frame->width ||
+            (avctx->container_crop_top + frame->crop_top + avctx->container_crop_bottom + frame->crop_bottom) >= frame->height) {
+            av_log(avctx, AV_LOG_WARNING,
+                "Apply container and elementary stream corpping parametes error: "
+                "container cropping paramters "
+                "%d/%d/%d/%d "
+                "elementary stream croping paramters "
+                "%"SIZE_SPECIFIER"/%"SIZE_SPECIFIER"/%"SIZE_SPECIFIER"/%"SIZE_SPECIFIER" "
+                "(frame size %dx%d). This is a bug, please report it\n",
+                avctx->container_crop_left, avctx->container_crop_right, avctx->container_crop_top, avctx->container_crop_bottom,
+                frame->crop_left, frame->crop_right, frame->crop_top, frame->crop_bottom,
+                frame->width, frame->height);
+            frame->crop_left   = 0;
+            frame->crop_right  = 0;
+            frame->crop_top    = 0;
+            frame->crop_bottom = 0;
+            return 0;
+        }
+
+        frame->crop_top    += (size_t)avctx->container_crop_top;
+        frame->crop_left   += (size_t)avctx->container_crop_left;
+        frame->crop_bottom += (size_t)avctx->container_crop_bottom;
+        frame->crop_right  += (size_t)avctx->container_crop_right;
+    }else if (avctx->container_apply_cropping == FF_CONTAINER_CROPPING_OVERWRITE) {
+
+        /*check the croppping parameters from container are reasonable and correct*/
+        if (avctx->container_crop_left >= INT_MAX - avctx->container_crop_right ||
+            avctx->container_crop_top >= INT_MAX - avctx->container_crop_bottom ||
+            (avctx->container_crop_left + avctx->container_crop_right) >= frame->width ||
+            (avctx->container_crop_top + avctx->container_crop_bottom) >= frame->height) {
+            av_log(avctx, AV_LOG_WARNING,
+                "Invalid container cropping information set by a demuxer: "
+                "%d/%d/%d/%d "
+                "(frame size %dx%d). This is a bug, please report it\n",
+                avctx->container_crop_left, avctx->container_crop_right, avctx->container_crop_top, avctx->container_crop_bottom,
+                frame->width, frame->height);
+            frame->crop_left = 0;
+            frame->crop_right = 0;
+            frame->crop_top = 0;
+            frame->crop_bottom = 0;
+            return 0;
+        }
+
+        frame->crop_top    = (size_t)avctx->container_crop_top;
+        frame->crop_left   = (size_t)avctx->container_crop_left;
+        frame->crop_bottom = (size_t)avctx->container_crop_bottom;
+        frame->crop_right  = (size_t)avctx->container_crop_right;
+    }
+
     return av_frame_apply_cropping(frame, avctx->flags & AV_CODEC_FLAG_UNALIGNED ?
                                           AV_FRAME_CROP_UNALIGNED : 0);
 }
-- 
2.30.0.windows.2

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