[FFmpeg-devel] [PATCH 4/6] cbs_apv: Better constrain tile_width/height_in_mbs

[Mark Thompson]

The maximum number of tile columns/rows adds an extra constraint on
the minimum tile width/height for large frames (over 5120 width or
2560 height).
---
 libavcodec/apv_decode.c              |  2 +-
 libavcodec/cbs_apv_syntax_template.c | 14 ++++++++++----
 2 files changed, 11 insertions(+), 5 deletions(-)

diff --git a/libavcodec/apv_decode.c b/libavcodec/apv_decode.c
index 7ee39e578a..7761a155ae 100644
--- a/libavcodec/apv_decode.c
+++ b/libavcodec/apv_decode.c
@@ -401,7 +401,7 @@ static int apv_decode_frame(AVCodecContext *avctx, AVFrame 
*frame,
     err = ff_cbs_read_packet(apv->cbc, au, packet);
     if (err < 0) {
         av_log(avctx, AV_LOG_ERROR, "Failed to read packet.\n");
-        return err;
+        goto fail;
     }
 
     for (int i = 0; i < au->nb_units; i++) {
diff --git a/libavcodec/cbs_apv_syntax_template.c 
b/libavcodec/cbs_apv_syntax_template.c
index fefffe17b7..b6681681d4 100644
--- a/libavcodec/cbs_apv_syntax_template.c
+++ b/libavcodec/cbs_apv_syntax_template.c
@@ -113,12 +113,18 @@ static int FUNC(tile_info)(CodedBitstreamContext *ctx, 
RWContext *rw,
                            const APVRawFrameHeader *fh)
 {
     CodedBitstreamAPVContext *priv = ctx->priv_data;
+    int frame_width_in_mbs   = (fh->frame_info.frame_width  + 15) / 16;
+    int frame_height_in_mbs  = (fh->frame_info.frame_height + 15) / 16;
+    uint32_t min_tile_width  = FFMAX(APV_MIN_TILE_WIDTH_IN_MBS,
+                                     (frame_width_in_mbs + APV_MAX_TILE_COLS - 
1) /
+                                     APV_MAX_TILE_COLS);
+    uint32_t min_tile_height = FFMAX(APV_MIN_TILE_HEIGHT_IN_MBS,
+                                     (frame_height_in_mbs + APV_MAX_TILE_ROWS 
- 1) /
+                                     APV_MAX_TILE_ROWS);
     int err;
 
-    u(20, tile_width_in_mbs,
-      APV_MIN_TILE_WIDTH_IN_MBS,  MAX_UINT_BITS(20));
-    u(20, tile_height_in_mbs,
-      APV_MIN_TILE_HEIGHT_IN_MBS, MAX_UINT_BITS(20));
+    u(20, tile_width_in_mbs,  min_tile_width,  MAX_UINT_BITS(20));
+    u(20, tile_height_in_mbs, min_tile_height, MAX_UINT_BITS(20));
 
     ub(1, tile_size_present_in_fh_flag);
 
-- 
2.47.2

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