h264: decouple h264_ps from the h264 decoder

Make the SPS/PPS parsing independent of the H264Context, to allow
decoupling the parser from the decoder. The change is modelled after the
one done earlier for HEVC.

Move the dequant buffers to the PPS to avoid complex checks whether they
changed and an expensive copy for frame threads.

1 files changed, 27 insertions, 21 deletions

diff --git a/libavcodec/h264.h b/libavcodec/h264.h
index 86625f3a13..6a026aa818 100644
--- a/libavcodec/h264.h
+++ b/libavcodec/h264.h
@@ -28,6 +28,7 @@
 #ifndef AVCODEC_H264_H
 #define AVCODEC_H264_H
 
+#include "libavutil/buffer.h"
 #include "libavutil/intreadwrite.h"
 #include "libavutil/thread.h"
 #include "cabac.h"
@@ -92,11 +93,11 @@
 #define FIELD_OR_MBAFF_PICTURE(h) (FRAME_MBAFF(h) || FIELD_PICTURE(h))
 
 #ifndef CABAC
-#define CABAC(h) h->pps.cabac
+#define CABAC(h) h->ps.pps->cabac
 #endif
 
-#define CHROMA422(h) (h->sps.chroma_format_idc == 2)
-#define CHROMA444(h) (h->sps.chroma_format_idc == 3)
+#define CHROMA422(h) (h->ps.sps->chroma_format_idc == 2)
+#define CHROMA444(h) (h->ps.sps->chroma_format_idc == 3)
 
 #define EXTENDED_SAR       255
 
@@ -214,7 +215,6 @@ typedef struct SPS {
     int bit_depth_chroma;                 ///< bit_depth_chroma_minus8 + 8
     int residual_color_transform_flag;    ///< residual_colour_transform_flag
     int constraint_set_flags;             ///< constraint_set[0-3]_flag
-    int new;                              ///< flag to keep track if the decoder context needs re-init due to changed SPS
 } SPS;
 
 /**
@@ -240,8 +240,23 @@ typedef struct PPS {
     uint8_t scaling_matrix8[6][64];
     uint8_t chroma_qp_table[2][64]; ///< pre-scaled (with chroma_qp_index_offset) version of qp_table
     int chroma_qp_diff;
+
+    uint32_t dequant4_buffer[6][QP_MAX_NUM + 1][16];
+    uint32_t dequant8_buffer[6][QP_MAX_NUM + 1][64];
+    uint32_t(*dequant4_coeff[6])[16];
+    uint32_t(*dequant8_coeff[6])[64];
 } PPS;
 
+typedef struct H264ParamSets {
+    AVBufferRef *sps_list[MAX_SPS_COUNT];
+    AVBufferRef *pps_list[MAX_PPS_COUNT];
+
+    /* currently active parameters sets */
+    const PPS *pps;
+    // FIXME this should properly be const
+    SPS *sps;
+} H264ParamSets;
+
 /**
  * Memory management control operation opcode.
  */
@@ -506,14 +521,6 @@ typedef struct H264Context {
     uint32_t *mb2br_xy;
     int b_stride;       // FIXME use s->b4_stride
 
-    SPS sps; ///< current sps
-    PPS pps; ///< current pps
-
-    uint32_t dequant4_buffer[6][QP_MAX_NUM + 1][16]; // FIXME should these be moved down?
-    uint32_t dequant8_buffer[6][QP_MAX_NUM + 1][64];
-    uint32_t(*dequant4_coeff[6])[16];
-    uint32_t(*dequant8_coeff[6])[64];
-
     uint16_t *slice_table;      ///< slice_table_base + 2*mb_stride + 1
 
     // interlacing specific flags
@@ -566,10 +573,7 @@ typedef struct H264Context {
     int bit_depth_luma;         ///< luma bit depth from sps to detect changes
     int chroma_format_idc;      ///< chroma format from sps to detect changes
 
-    SPS *sps_buffers[MAX_SPS_COUNT];
-    PPS *pps_buffers[MAX_PPS_COUNT];
-
-    int dequant_coeff_pps;      ///< reinit tables when pps changes
+    H264ParamSets ps;
 
     uint16_t *slice_table_base;
 
@@ -756,17 +760,19 @@ int ff_h264_decode_sei(H264Context *h);
 /**
  * Decode SPS
  */
-int ff_h264_decode_seq_parameter_set(H264Context *h);
+int ff_h264_decode_seq_parameter_set(GetBitContext *gb, AVCodecContext *avctx,
+                                     H264ParamSets *ps);
 
 /**
  * compute profile from sps
  */
-int ff_h264_get_profile(SPS *sps);
+int ff_h264_get_profile(const SPS *sps);
 
 /**
  * Decode PPS
  */
-int ff_h264_decode_picture_parameter_set(H264Context *h, int bit_length);
+int ff_h264_decode_picture_parameter_set(GetBitContext *gb, AVCodecContext *avctx,
+                                         H264ParamSets *ps, int bit_length);
 
 /**
  * Free any data that may have been allocated in the H264 context
@@ -912,7 +918,7 @@ static av_always_inline uint16_t pack8to16(int a, int b)
  */
 static av_always_inline int get_chroma_qp(const H264Context *h, int t, int qscale)
 {
-    return h->pps.chroma_qp_table[t][qscale];
+    return h->ps.pps->chroma_qp_table[t][qscale];
 }
 
 /**
@@ -1035,7 +1041,7 @@ static av_always_inline void write_back_motion(const H264Context *h,
 
 static av_always_inline int get_dct8x8_allowed(const H264Context *h, H264SliceContext *sl)
 {
-    if (h->sps.direct_8x8_inference_flag)
+    if (h->ps.sps->direct_8x8_inference_flag)
         return !(AV_RN64A(sl->sub_mb_type) &
                  ((MB_TYPE_16x8 | MB_TYPE_8x16 | MB_TYPE_8x8) *
                   0x0001000100010001ULL));