[FFmpeg-devel] [PATCH v2 6/8] avcodec/h264dec: add ref_pic_marking and pic_order_cnt bit_size to slice context

[Jonas Karlman]

From: Boris Brezillon <boris.brezillon at collabora.com>

The V4L2_CID_STATELESS_H264_DECODE_PARAMS control require following:

- dec_ref_pic_marking_bit_size
  Size in bits of the dec_ref_pic_marking() syntax element.

- pic_order_cnt_bit_size
  Combined size in bits of the picture order count related syntax
  elements: pic_order_cnt_lsb, delta_pic_order_cnt_bottom,
  delta_pic_order_cnt0, and delta_pic_order_cnt1.

Save the bit sizes while parsing for later use in hwaccel, similar to
short/long_term_ref_pic_set_size in hevcdec.

Signed-off-by: Boris Brezillon <boris.brezillon at collabora.com>
Signed-off-by: Jonas Karlman <jonas at kwiboo.se>
---
 libavcodec/h264_slice.c | 6 +++++-
 libavcodec/h264dec.h    | 2 ++
 2 files changed, 7 insertions(+), 1 deletion(-)

diff --git a/libavcodec/h264_slice.c b/libavcodec/h264_slice.c
index a66b75ca80..58a48f3fbe 100644
--- a/libavcodec/h264_slice.c
+++ b/libavcodec/h264_slice.c
@@ -1690,7 +1690,7 @@ static int h264_slice_header_parse(const H264Context *h, H264SliceContext *sl,
     unsigned int slice_type, tmp, i;
     int field_pic_flag, bottom_field_flag;
     int first_slice = sl == h->slice_ctx && !h->current_slice;
-    int picture_structure;
+    int picture_structure, pos;
 
     if (first_slice)
         av_assert0(!h->setup_finished);
@@ -1781,6 +1781,7 @@ static int h264_slice_header_parse(const H264Context *h, H264SliceContext *sl,
 
     sl->poc_lsb = 0;
     sl->delta_poc_bottom = 0;
+    pos = get_bits_left(&sl->gb);
     if (sps->poc_type == 0) {
         sl->poc_lsb = get_bits(&sl->gb, sps->log2_max_poc_lsb);
 
@@ -1795,6 +1796,7 @@ static int h264_slice_header_parse(const H264Context *h, H264SliceContext *sl,
         if (pps->pic_order_present == 1 && picture_structure == PICT_FRAME)
             sl->delta_poc[1] = get_se_golomb(&sl->gb);
     }
+    sl->pic_order_cnt_bit_size = pos - get_bits_left(&sl->gb);
 
     sl->redundant_pic_count = 0;
     if (pps->redundant_pic_cnt_present)
@@ -1834,9 +1836,11 @@ static int h264_slice_header_parse(const H264Context *h, H264SliceContext *sl,
 
     sl->explicit_ref_marking = 0;
     if (nal->ref_idc) {
+        pos = get_bits_left(&sl->gb);
         ret = ff_h264_decode_ref_pic_marking(sl, &sl->gb, nal, h->avctx);
         if (ret < 0 && (h->avctx->err_recognition & AV_EF_EXPLODE))
             return AVERROR_INVALIDDATA;
+        sl->ref_pic_marking_bit_size = pos - get_bits_left(&sl->gb);
     }
 
     if (sl->slice_type_nos != AV_PICTURE_TYPE_I && pps->cabac) {
diff --git a/libavcodec/h264dec.h b/libavcodec/h264dec.h
index ccd7583bf4..71cbb0e0cc 100644
--- a/libavcodec/h264dec.h
+++ b/libavcodec/h264dec.h
@@ -324,6 +324,7 @@ typedef struct H264SliceContext {
     MMCO mmco[H264_MAX_MMCO_COUNT];
     int  nb_mmco;
     int explicit_ref_marking;
+    int ref_pic_marking_bit_size;
 
     int frame_num;
     int idr_pic_id;
@@ -332,6 +333,7 @@ typedef struct H264SliceContext {
     int delta_poc[2];
     int curr_pic_num;
     int max_pic_num;
+    int pic_order_cnt_bit_size;
 } H264SliceContext;
 
 /**
-- 
2.45.2