[FFmpeg-devel] [PATCH 04/11] lavc/hevcdec: drop HEVCLocalContext.gb
Anton Khirnov
anton at khirnov.net
Fri May 31 20:47:42 EEST 2024
In all HEVCLocalContext instances except the first one, the bitreader is
never used for actually reading bits, but merely for passing the buffer
to ff_init_cabac_decoder(), which is better done directly.
The instance that actually is used for bitreading gets moved to stack in
decode_nal_unit(), which makes its lifetime clearer.
---
libavcodec/hevc_cabac.c | 17 +++++-----------
libavcodec/hevcdec.c | 43 +++++++++++++++++++----------------------
libavcodec/hevcdec.h | 4 ++--
3 files changed, 27 insertions(+), 37 deletions(-)
diff --git a/libavcodec/hevc_cabac.c b/libavcodec/hevc_cabac.c
index 3f95c9ca05..71bd678972 100644
--- a/libavcodec/hevc_cabac.c
+++ b/libavcodec/hevc_cabac.c
@@ -427,14 +427,6 @@ static int cabac_reinit(HEVCLocalContext *lc)
return skip_bytes(&lc->cc, 0) == NULL ? AVERROR_INVALIDDATA : 0;
}
-static int cabac_init_decoder(HEVCLocalContext *lc)
-{
- GetBitContext *gb = &lc->gb;
- return ff_init_cabac_decoder(&lc->cc,
- gb->buffer + get_bits_count(gb) / 8,
- (get_bits_left(gb) + 7) / 8);
-}
-
static void cabac_init_state(HEVCLocalContext *lc, const HEVCContext *s)
{
int init_type = 2 - s->sh.slice_type;
@@ -459,12 +451,13 @@ static void cabac_init_state(HEVCLocalContext *lc, const HEVCContext *s)
lc->stat_coeff[i] = 0;
}
-int ff_hevc_cabac_init(HEVCLocalContext *lc, int ctb_addr_ts)
+int ff_hevc_cabac_init(HEVCLocalContext *lc, int ctb_addr_ts,
+ const uint8_t *data, size_t size)
{
const HEVCContext *const s = lc->parent;
if (ctb_addr_ts == s->ps.pps->ctb_addr_rs_to_ts[s->sh.slice_ctb_addr_rs]) {
- int ret = cabac_init_decoder(lc);
+ int ret = ff_init_cabac_decoder(&lc->cc, data, size);
if (ret < 0)
return ret;
if (s->sh.dependent_slice_segment_flag == 0 ||
@@ -488,7 +481,7 @@ int ff_hevc_cabac_init(HEVCLocalContext *lc, int ctb_addr_ts)
if (s->threads_number == 1)
ret = cabac_reinit(lc);
else {
- ret = cabac_init_decoder(lc);
+ ret = ff_init_cabac_decoder(&lc->cc, data, size);
}
if (ret < 0)
return ret;
@@ -501,7 +494,7 @@ int ff_hevc_cabac_init(HEVCLocalContext *lc, int ctb_addr_ts)
if (s->threads_number == 1)
ret = cabac_reinit(lc);
else {
- ret = cabac_init_decoder(lc);
+ ret = ff_init_cabac_decoder(&lc->cc, data, size);
}
if (ret < 0)
return ret;
diff --git a/libavcodec/hevcdec.c b/libavcodec/hevcdec.c
index 42fd33961b..0a9443505a 100644
--- a/libavcodec/hevcdec.c
+++ b/libavcodec/hevcdec.c
@@ -593,9 +593,8 @@ fail:
return ret;
}
-static int hls_slice_header(HEVCContext *s)
+static int hls_slice_header(HEVCContext *s, GetBitContext *gb)
{
- GetBitContext *gb = &s->HEVClc->gb;
SliceHeader *sh = &s->sh;
int i, ret;
@@ -2533,9 +2532,11 @@ static void hls_decode_neighbour(HEVCLocalContext *lc, int x_ctb, int y_ctb,
lc->ctb_up_left_flag = ((x_ctb > 0) && (y_ctb > 0) && (ctb_addr_in_slice-1 >= s->ps.sps->ctb_width) && (s->ps.pps->tile_id[ctb_addr_ts] == s->ps.pps->tile_id[s->ps.pps->ctb_addr_rs_to_ts[ctb_addr_rs-1 - s->ps.sps->ctb_width]]));
}
-static int hls_decode_entry(HEVCContext *s)
+static int hls_decode_entry(HEVCContext *s, GetBitContext *gb)
{
HEVCLocalContext *const lc = s->HEVClc;
+ const uint8_t *slice_data = gb->buffer + s->sh.data_offset;
+ const size_t slice_size = gb->buffer_end - gb->buffer - s->sh.data_offset;
int ctb_size = 1 << s->ps.sps->log2_ctb_size;
int more_data = 1;
int x_ctb = 0;
@@ -2563,7 +2564,7 @@ static int hls_decode_entry(HEVCContext *s)
y_ctb = (ctb_addr_rs / ((s->ps.sps->width + ctb_size - 1) >> s->ps.sps->log2_ctb_size)) << s->ps.sps->log2_ctb_size;
hls_decode_neighbour(lc, x_ctb, y_ctb, ctb_addr_ts);
- ret = ff_hevc_cabac_init(lc, ctb_addr_ts);
+ ret = ff_hevc_cabac_init(lc, ctb_addr_ts, slice_data, slice_size);
if (ret < 0) {
s->tab_slice_address[ctb_addr_rs] = -1;
return ret;
@@ -2605,14 +2606,14 @@ static int hls_decode_entry_wpp(AVCodecContext *avctxt, void *hevc_lclist,
int ctb_addr_rs = s->sh.slice_ctb_addr_rs + ctb_row * ((s->ps.sps->width + ctb_size - 1) >> s->ps.sps->log2_ctb_size);
int ctb_addr_ts = s->ps.pps->ctb_addr_rs_to_ts[ctb_addr_rs];
int thread = ctb_row % s->threads_number;
+
+ const uint8_t *data = s->data + s->sh.offset[ctb_row];
+ const size_t data_size = s->sh.size[ctb_row];
+
int ret;
- if(ctb_row) {
- ret = init_get_bits8(&lc->gb, s->data + s->sh.offset[ctb_row], s->sh.size[ctb_row]);
- if (ret < 0)
- goto error;
- ff_init_cabac_decoder(&lc->cc, s->data + s->sh.offset[ctb_row], s->sh.size[ctb_row]);
- }
+ if (ctb_row)
+ ff_init_cabac_decoder(&lc->cc, data, data_size);
while(more_data && ctb_addr_ts < s->ps.sps->ctb_size) {
int x_ctb = (ctb_addr_rs % s->ps.sps->ctb_width) << s->ps.sps->log2_ctb_size;
@@ -2630,7 +2631,7 @@ static int hls_decode_entry_wpp(AVCodecContext *avctxt, void *hevc_lclist,
return 0;
}
- ret = ff_hevc_cabac_init(lc, ctb_addr_ts);
+ ret = ff_hevc_cabac_init(lc, ctb_addr_ts, data, data_size);
if (ret < 0)
goto error;
hls_sao_param(lc, x_ctb >> s->ps.sps->log2_ctb_size, y_ctb >> s->ps.sps->log2_ctb_size);
@@ -2681,7 +2682,6 @@ static int hls_slice_data_wpp(HEVCContext *s, const H2645NAL *nal)
{
const uint8_t *data = nal->data;
int length = nal->size;
- HEVCLocalContext *lc;
int *ret;
int64_t offset;
int64_t startheader, cmpt = 0;
@@ -2719,8 +2719,7 @@ static int hls_slice_data_wpp(HEVCContext *s, const H2645NAL *nal)
s->nb_local_ctx = s->threads_number;
}
- lc = &s->local_ctx[0];
- offset = (lc->gb.index >> 3);
+ offset = s->sh.data_offset;
for (j = 0, cmpt = 0, startheader = offset + s->sh.entry_point_offset[0]; j < nal->skipped_bytes; j++) {
if (nal->skipped_bytes_pos[j] >= offset && nal->skipped_bytes_pos[j] < startheader) {
@@ -2981,11 +2980,9 @@ static int hevc_frame_end(HEVCContext *s)
static int decode_nal_unit(HEVCContext *s, const H2645NAL *nal)
{
- HEVCLocalContext *lc = s->HEVClc;
- GetBitContext *gb = &lc->gb;
+ GetBitContext gb = nal->gb;
int ctb_addr_ts, ret;
- *gb = nal->gb;
s->nal_unit_type = nal->type;
s->temporal_id = nal->temporal_id;
@@ -2997,7 +2994,7 @@ static int decode_nal_unit(HEVCContext *s, const H2645NAL *nal)
if (ret < 0)
goto fail;
}
- ret = ff_hevc_decode_nal_vps(gb, s->avctx, &s->ps);
+ ret = ff_hevc_decode_nal_vps(&gb, s->avctx, &s->ps);
if (ret < 0)
goto fail;
break;
@@ -3008,7 +3005,7 @@ static int decode_nal_unit(HEVCContext *s, const H2645NAL *nal)
if (ret < 0)
goto fail;
}
- ret = ff_hevc_decode_nal_sps(gb, s->avctx, &s->ps,
+ ret = ff_hevc_decode_nal_sps(&gb, s->avctx, &s->ps,
s->apply_defdispwin);
if (ret < 0)
goto fail;
@@ -3020,7 +3017,7 @@ static int decode_nal_unit(HEVCContext *s, const H2645NAL *nal)
if (ret < 0)
goto fail;
}
- ret = ff_hevc_decode_nal_pps(gb, s->avctx, &s->ps);
+ ret = ff_hevc_decode_nal_pps(&gb, s->avctx, &s->ps);
if (ret < 0)
goto fail;
break;
@@ -3032,7 +3029,7 @@ static int decode_nal_unit(HEVCContext *s, const H2645NAL *nal)
if (ret < 0)
goto fail;
}
- ret = ff_hevc_decode_nal_sei(gb, s->avctx, &s->sei, &s->ps, s->nal_unit_type);
+ ret = ff_hevc_decode_nal_sei(&gb, s->avctx, &s->sei, &s->ps, s->nal_unit_type);
if (ret < 0)
goto fail;
break;
@@ -3052,7 +3049,7 @@ static int decode_nal_unit(HEVCContext *s, const H2645NAL *nal)
case HEVC_NAL_RADL_R:
case HEVC_NAL_RASL_N:
case HEVC_NAL_RASL_R:
- ret = hls_slice_header(s);
+ ret = hls_slice_header(s, &gb);
if (ret < 0)
return ret;
if (ret == 1) {
@@ -3134,7 +3131,7 @@ static int decode_nal_unit(HEVCContext *s, const H2645NAL *nal)
if (s->threads_number > 1 && s->sh.num_entry_point_offsets > 0)
ctb_addr_ts = hls_slice_data_wpp(s, nal);
else
- ctb_addr_ts = hls_decode_entry(s);
+ ctb_addr_ts = hls_decode_entry(s, &gb);
if (ctb_addr_ts >= (s->ps.sps->ctb_width * s->ps.sps->ctb_height)) {
ret = hevc_frame_end(s);
if (ret < 0)
diff --git a/libavcodec/hevcdec.h b/libavcodec/hevcdec.h
index 3824bf621b..0ed51a5392 100644
--- a/libavcodec/hevcdec.h
+++ b/libavcodec/hevcdec.h
@@ -394,7 +394,6 @@ typedef struct HEVCLocalContext {
void *logctx;
const struct HEVCContext *parent;
- GetBitContext gb;
CABACContext cc;
/**
@@ -583,7 +582,8 @@ int ff_hevc_frame_rps(HEVCContext *s);
int ff_hevc_slice_rpl(HEVCContext *s);
void ff_hevc_save_states(HEVCLocalContext *lc, int ctb_addr_ts);
-int ff_hevc_cabac_init(HEVCLocalContext *lc, int ctb_addr_ts);
+int ff_hevc_cabac_init(HEVCLocalContext *lc, int ctb_addr_ts,
+ const uint8_t *data, size_t size);
int ff_hevc_sao_merge_flag_decode(HEVCLocalContext *lc);
int ff_hevc_sao_type_idx_decode(HEVCLocalContext *lc);
int ff_hevc_sao_band_position_decode(HEVCLocalContext *lc);
--
2.43.0
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