cbs_h264: Fix default value for max mv lengths

A recent version of the standard changed the max and default to 15, from
16 in older versions.  This updates the default to 15 to match, but the
max stays as 16 so that we don't reject older streams.

diff --git a/libavcodec/cbs_h264_syntax_template.c b/libavcodec/cbs_h264_syntax_template.c
index 027b555db65de55e109fa56d35e87f64102f8a46..1efa97dccb8a58b5bf5afbaa261e851e266bac55 100644 (file)
--- a/libavcodec/cbs_h264_syntax_template.c
+++ b/libavcodec/cbs_h264_syntax_template.c
@@ -185,6 +185,8 @@ static int FUNC(vui_parameters)(CodedBitstreamContext *ctx, RWContext *rw,
         flag(motion_vectors_over_pic_boundaries_flag);
         ue(max_bytes_per_pic_denom, 0, 16);
         ue(max_bits_per_mb_denom,   0, 16);
+        // The current version of the standard constrains this to be in
+        // [0,15], but older versions allow 16.
         ue(log2_max_mv_length_horizontal, 0, 16);
         ue(log2_max_mv_length_vertical,   0, 16);
         ue(max_num_reorder_frames,  0, H264_MAX_DPB_FRAMES);
@@ -193,8 +195,8 @@ static int FUNC(vui_parameters)(CodedBitstreamContext *ctx, RWContext *rw,
         infer(motion_vectors_over_pic_boundaries_flag, 1);
         infer(max_bytes_per_pic_denom, 2);
         infer(max_bits_per_mb_denom,   1);
-        infer(log2_max_mv_length_horizontal, 16);
-        infer(log2_max_mv_length_vertical,   16);
+        infer(log2_max_mv_length_horizontal, 15);
+        infer(log2_max_mv_length_vertical,   15);
 
         if ((sps->profile_idc ==  44 || sps->profile_idc ==  86 ||
              sps->profile_idc == 110 || sps->profile_idc == 110 ||

diff --git a/libavcodec/vaapi_encode_h264.c b/libavcodec/vaapi_encode_h264.c
index e55ed0f59c8f25d3106e15719419a8f72f535bfc..8feae0d42fb1036d209b788c859a004bf754c552 100644 (file)
--- a/libavcodec/vaapi_encode_h264.c
+++ b/libavcodec/vaapi_encode_h264.c
@@ -491,8 +491,8 @@ static int vaapi_encode_h264_init_sequence_params(AVCodecContext *avctx)
 
     sps->vui.bitstream_restriction_flag    = 1;
     sps->vui.motion_vectors_over_pic_boundaries_flag = 1;
-    sps->vui.log2_max_mv_length_horizontal = 16;
-    sps->vui.log2_max_mv_length_vertical   = 16;
+    sps->vui.log2_max_mv_length_horizontal = 15;
+    sps->vui.log2_max_mv_length_vertical   = 15;
     sps->vui.max_num_reorder_frames        = (ctx->b_per_p > 0);
     sps->vui.max_dec_frame_buffering       = sps->max_num_ref_frames;