[FFmpeg-devel] [PATCH 1/3] avcodec/h265_metadata: Add options to set width/height after crop

[Zhao Zhili <quinkblack@foxmail.com>]

From: Zhao Zhili <zhilizhao@tencent.com>

It's a common usecase to request a video size after crop. Before
this patch, user must know the video size before crop, then set
crop_right/crop_bottom accordingly. Since HEVC can have different
CTU size, it's not easy to get/deduce the video size before crop.
With the new width/height options, there is no such requirement.

Signed-off-by: Zhao Zhili <zhilizhao@tencent.com>
---
 doc/bitstream_filters.texi     |   4 ++
 libavcodec/bsf/h265_metadata.c | 101 ++++++++++++++++++++++++++++++++-
 libavcodec/version.h           |   2 +-
 3 files changed, 103 insertions(+), 4 deletions(-)

diff --git a/doc/bitstream_filters.texi b/doc/bitstream_filters.texi
index 3d4dda04fc..c03f04f858 100644
--- a/doc/bitstream_filters.texi
+++ b/doc/bitstream_filters.texi
@@ -456,6 +456,10 @@ will replace the current ones if the stream is already cropped.
 These fields are set in pixels.  Note that some sizes may not be
 representable if the chroma is subsampled (H.265 section 7.4.3.2.1).
 
+@item width
+@item height
+Set width and height after crop.
+
 @item level
 Set the level in the VPS and SPS.  See H.265 section A.4 and tables
 A.6 and A.7.
diff --git a/libavcodec/bsf/h265_metadata.c b/libavcodec/bsf/h265_metadata.c
index c9e1cc3eed..eba00c20d5 100644
--- a/libavcodec/bsf/h265_metadata.c
+++ b/libavcodec/bsf/h265_metadata.c
@@ -58,6 +58,8 @@ typedef struct H265MetadataContext {
     int crop_right;
     int crop_top;
     int crop_bottom;
+    int width;
+    int height;
 
     int level;
     int level_guess;
@@ -187,12 +189,94 @@ static int h265_metadata_update_vps(AVBSFContext *bsf,
     return 0;
 }
 
+static int h265_metadata_deduce_crop(AVBSFContext *bsf, const H265RawSPS *sps,
+                                     int *crop_left, int *crop_right,
+                                     int *crop_top, int *crop_bottom)
+{
+    const H265MetadataContext *ctx = bsf->priv_data;
+    int left = ctx->crop_left;
+    int right = ctx->crop_right;
+    int top = ctx->crop_top;
+    int bottom = ctx->crop_bottom;
+
+    if (ctx->width > 0) {
+        if (ctx->width > sps->pic_width_in_luma_samples) {
+            av_log(bsf, AV_LOG_ERROR,
+                   "The width option value %d is larger than picture width %d\n",
+                   ctx->width, sps->pic_width_in_luma_samples);
+            return AVERROR(EINVAL);
+        }
+
+        if (left < 0) {
+            if (right > 0)
+                left = sps->pic_width_in_luma_samples - ctx->width - right;
+            else
+                left = 0;
+        }
+
+        if (right < 0)
+            right = sps->pic_width_in_luma_samples - ctx->width - left;
+
+        if (left < 0 || right < 0 || (left + right + ctx->width) !=
+            sps->pic_width_in_luma_samples) {
+            av_log(bsf, AV_LOG_ERROR,
+                   "Invalid value for crop_left %d, crop_right %d, width after "
+                   "crop %d, with picture width %d\n",
+                   ctx->crop_left, ctx->crop_right, ctx->width,
+                   sps->pic_width_in_luma_samples);
+            return AVERROR(EINVAL);
+        }
+    }
+
+    if (ctx->height > 0) {
+        if (ctx->height > sps->pic_height_in_luma_samples) {
+            av_log(bsf, AV_LOG_ERROR,
+                   "The height option value %d is larger than picture height %d\n",
+                   ctx->height, sps->pic_height_in_luma_samples);
+            return AVERROR(EINVAL);
+        }
+
+        if (top < 0) {
+            if (bottom > 0)
+                top = sps->pic_height_in_luma_samples - ctx->height - bottom;
+            else
+                top = 0;
+        }
+
+        if (bottom < 0)
+            bottom = sps->pic_height_in_luma_samples - ctx->height - top;
+
+        if (top < 0 || bottom < 0 || (top + bottom + ctx->height) !=
+            sps->pic_height_in_luma_samples) {
+            av_log(bsf, AV_LOG_ERROR,
+                   "Invalid value for crop_top %d, crop_bottom %d, height after "
+                   "crop %d, with picture height %d\n",
+                   ctx->crop_top, ctx->crop_bottom, ctx->height,
+                   sps->pic_height_in_luma_samples);
+            return AVERROR(EINVAL);
+        }
+    }
+
+    *crop_left = left;
+    *crop_right = right;
+    *crop_top = top;
+    *crop_bottom = bottom;
+
+    return 0;
+}
+
 static int h265_metadata_update_sps(AVBSFContext *bsf,
                                     H265RawSPS *sps)
 {
     H265MetadataContext *ctx = bsf->priv_data;
     int need_vui = 0;
     int crop_unit_x, crop_unit_y;
+    /* Use local variables to avoid modifying context fields in case of video
+     * resolution changed. Crop doesn't work well with resolution change, this
+     * is the best we can do.
+     */
+    int crop_left, crop_right, crop_top, crop_bottom;
+    int ret;
 
     if (ctx->sample_aspect_ratio.num && ctx->sample_aspect_ratio.den) {
         int num, den, i;
@@ -289,6 +373,11 @@ static int h265_metadata_update_sps(AVBSFContext *bsf,
         }
     }
 
+    ret = h265_metadata_deduce_crop(bsf, sps, &crop_left, &crop_right,
+                                    &crop_top, &crop_bottom);
+    if (ret < 0)
+        return ret;
+
     if (sps->separate_colour_plane_flag || sps->chroma_format_idc == 0) {
         crop_unit_x = 1;
         crop_unit_y = 1;
@@ -297,14 +386,14 @@ static int h265_metadata_update_sps(AVBSFContext *bsf,
         crop_unit_y = 1 + (sps->chroma_format_idc < 2);
     }
 #define CROP(border, unit) do { \
-        if (ctx->crop_ ## border >= 0) { \
-            if (ctx->crop_ ## border % unit != 0) { \
+        if (crop_ ## border >= 0) { \
+            if (crop_ ## border % unit != 0) { \
                 av_log(bsf, AV_LOG_ERROR, "Invalid value for crop_%s: " \
                        "must be a multiple of %d.\n", #border, unit); \
                 return AVERROR(EINVAL); \
             } \
             sps->conf_win_ ## border ## _offset = \
-                ctx->crop_ ## border / unit; \
+                crop_ ## border / unit; \
             sps->conformance_window_flag = 1; \
         } \
     } while (0)
@@ -453,6 +542,12 @@ static const AVOption h265_metadata_options[] = {
     { "crop_bottom", "Set bottom border crop offset",
         OFFSET(crop_bottom), AV_OPT_TYPE_INT,
         { .i64 = -1 }, -1, HEVC_MAX_HEIGHT, FLAGS },
+    { "width", "Set width after crop",
+        OFFSET(width), AV_OPT_TYPE_INT,
+        { .i64 = -1 }, -1, HEVC_MAX_WIDTH, FLAGS },
+    { "height", "Set height after crop",
+        OFFSET(height), AV_OPT_TYPE_INT,
+        { .i64 = -1 }, -1, HEVC_MAX_HEIGHT, FLAGS },
 
     { "level", "Set level (tables A.6 and A.7)",
         OFFSET(level), AV_OPT_TYPE_INT,
diff --git a/libavcodec/version.h b/libavcodec/version.h
index 3d2de546b3..f9b09b4b25 100644
--- a/libavcodec/version.h
+++ b/libavcodec/version.h
@@ -30,7 +30,7 @@
 #include "version_major.h"
 
 #define LIBAVCODEC_VERSION_MINOR   5
-#define LIBAVCODEC_VERSION_MICRO 104
+#define LIBAVCODEC_VERSION_MICRO 105
 
 #define LIBAVCODEC_VERSION_INT  AV_VERSION_INT(LIBAVCODEC_VERSION_MAJOR, \
                                                LIBAVCODEC_VERSION_MINOR, \
-- 
2.42.0

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