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FFmpeg/libavformat/av1.c
Andreas Rheinhardt 36fa84e7ac avformat/av1: Avoid using dynamic buffer when assembling av1c 
Given that AV1 only has exactly one sequence header, it is unnecessary
to copy the content of said sequence header into an intermediate dynamic
buffer; instead the sequence header can be copied from where it is in
the input buffer.

Signed-off-by: Andreas Rheinhardt <andreas.rheinhardt@gmail.com>
2020-06-26 07:12:31 +02:00

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/*
* AV1 helper functions for muxers
* Copyright (c) 2018 James Almer <jamrial@gmail.com>
*
* This file is part of FFmpeg.
*
* FFmpeg is free software; you can redistribute it and/or
* modify it under the terms of the GNU Lesser General Public
* License as published by the Free Software Foundation; either
* version 2.1 of the License, or (at your option) any later version.
*
* FFmpeg is distributed in the hope that it will be useful,
* but WITHOUT ANY WARRANTY; without even the implied warranty of
* MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
* Lesser General Public License for more details.
*
* You should have received a copy of the GNU Lesser General Public
* License along with FFmpeg; if not, write to the Free Software
* Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA
*/
#include "libavutil/avassert.h"
#include "libavutil/mem.h"
#include "libavcodec/av1.h"
#include "libavcodec/av1_parse.h"
#include "libavcodec/profiles.h"
#include "libavcodec/put_bits.h"
#include "av1.h"
#include "avio.h"
#include "avio_internal.h"
static int av1_filter_obus(AVIOContext *pb, const uint8_t *buf,
int size, int *offset)
{
const uint8_t *start = buf, *end = buf + size;
int64_t obu_size;
int off, start_pos, type, temporal_id, spatial_id;
enum {
START_NOT_FOUND,
START_FOUND,
END_FOUND,
OFFSET_IMPOSSIBLE,
} state = START_NOT_FOUND;
off = size = 0;
while (buf < end) {
int len = parse_obu_header(buf, end - buf, &obu_size, &start_pos,
&type, &temporal_id, &spatial_id);
if (len < 0)
return len;
switch (type) {
case AV1_OBU_TEMPORAL_DELIMITER:
case AV1_OBU_REDUNDANT_FRAME_HEADER:
case AV1_OBU_TILE_LIST:
case AV1_OBU_PADDING:
if (state == START_FOUND)
state = END_FOUND;
break;
default:
if (state == START_NOT_FOUND) {
off = buf - start;
state = START_FOUND;
} else if (state == END_FOUND) {
state = OFFSET_IMPOSSIBLE;
}
if (pb)
avio_write(pb, buf, len);
size += len;
break;
}
buf += len;
}
if (offset)
*offset = state != OFFSET_IMPOSSIBLE ? off : -1;
return size;
}
int ff_av1_filter_obus(AVIOContext *pb, const uint8_t *buf, int size)
{
return av1_filter_obus(pb, buf, size, NULL);
}
int ff_av1_filter_obus_buf(const uint8_t *in, uint8_t **out,
int *size, int *offset)
{
AVIOContext pb;
uint8_t *buf;
int len, off, ret;
len = ret = av1_filter_obus(NULL, in, *size, &off);
if (ret < 0) {
return ret;
}
if (off >= 0) {
*out = (uint8_t *)in;
*size = len;
*offset = off;
return 0;
}
buf = av_malloc(len + AV_INPUT_BUFFER_PADDING_SIZE);
if (!buf)
return AVERROR(ENOMEM);
ffio_init_context(&pb, buf, len, 1, NULL, NULL, NULL, NULL);
ret = av1_filter_obus(&pb, in, *size, NULL);
av_assert1(ret == len);
memset(buf + len, 0, AV_INPUT_BUFFER_PADDING_SIZE);
*out = buf;
*size = len;
*offset = 0;
return 0;
}
static inline void uvlc(GetBitContext *gb)
{
int leading_zeros = 0;
while (get_bits_left(gb)) {
if (get_bits1(gb))
break;
leading_zeros++;
}
if (leading_zeros >= 32)
return;
skip_bits_long(gb, leading_zeros);
}
static int parse_color_config(AV1SequenceParameters *seq_params, GetBitContext *gb)
{
int twelve_bit = 0;
int high_bitdepth = get_bits1(gb);
if (seq_params->profile == FF_PROFILE_AV1_PROFESSIONAL && high_bitdepth)
twelve_bit = get_bits1(gb);
seq_params->bitdepth = 8 + (high_bitdepth * 2) + (twelve_bit * 2);
if (seq_params->profile == FF_PROFILE_AV1_HIGH)
seq_params->monochrome = 0;
else
seq_params->monochrome = get_bits1(gb);
seq_params->color_description_present_flag = get_bits1(gb);
if (seq_params->color_description_present_flag) {
seq_params->color_primaries = get_bits(gb, 8);
seq_params->transfer_characteristics = get_bits(gb, 8);
seq_params->matrix_coefficients = get_bits(gb, 8);
} else {
seq_params->color_primaries = AVCOL_PRI_UNSPECIFIED;
seq_params->transfer_characteristics = AVCOL_TRC_UNSPECIFIED;
seq_params->matrix_coefficients = AVCOL_SPC_UNSPECIFIED;
}
if (seq_params->monochrome) {
seq_params->color_range = get_bits1(gb);
seq_params->chroma_subsampling_x = 1;
seq_params->chroma_subsampling_y = 1;
seq_params->chroma_sample_position = 0;
return 0;
} else if (seq_params->color_primaries == AVCOL_PRI_BT709 &&
seq_params->transfer_characteristics == AVCOL_TRC_IEC61966_2_1 &&
seq_params->matrix_coefficients == AVCOL_SPC_RGB) {
seq_params->chroma_subsampling_x = 0;
seq_params->chroma_subsampling_y = 0;
} else {
seq_params->color_range = get_bits1(gb);
if (seq_params->profile == FF_PROFILE_AV1_MAIN) {
seq_params->chroma_subsampling_x = 1;
seq_params->chroma_subsampling_y = 1;
} else if (seq_params->profile == FF_PROFILE_AV1_HIGH) {
seq_params->chroma_subsampling_x = 0;
seq_params->chroma_subsampling_y = 0;
} else {
if (twelve_bit) {
seq_params->chroma_subsampling_x = get_bits1(gb);
if (seq_params->chroma_subsampling_x)
seq_params->chroma_subsampling_y = get_bits1(gb);
else
seq_params->chroma_subsampling_y = 0;
} else {
seq_params->chroma_subsampling_x = 1;
seq_params->chroma_subsampling_y = 0;
}
}
if (seq_params->chroma_subsampling_x && seq_params->chroma_subsampling_y)
seq_params->chroma_sample_position = get_bits(gb, 2);
}
skip_bits1(gb); // separate_uv_delta_q
return 0;
}
static int parse_sequence_header(AV1SequenceParameters *seq_params, const uint8_t *buf, int size)
{
GetBitContext gb;
int reduced_still_picture_header;
int frame_width_bits_minus_1, frame_height_bits_minus_1;
int size_bits, ret;
size_bits = get_obu_bit_length(buf, size, AV1_OBU_SEQUENCE_HEADER);
if (size_bits < 0)
return size_bits;
ret = init_get_bits(&gb, buf, size_bits);
if (ret < 0)
return ret;
memset(seq_params, 0, sizeof(*seq_params));
seq_params->profile = get_bits(&gb, 3);
skip_bits1(&gb); // still_picture
reduced_still_picture_header = get_bits1(&gb);
if (reduced_still_picture_header) {
seq_params->level = get_bits(&gb, 5);
seq_params->tier = 0;
} else {
int initial_display_delay_present_flag, operating_points_cnt_minus_1;
int decoder_model_info_present_flag, buffer_delay_length_minus_1;
if (get_bits1(&gb)) { // timing_info_present_flag
skip_bits_long(&gb, 32); // num_units_in_display_tick
skip_bits_long(&gb, 32); // time_scale
if (get_bits1(&gb)) // equal_picture_interval
uvlc(&gb); // num_ticks_per_picture_minus_1
decoder_model_info_present_flag = get_bits1(&gb);
if (decoder_model_info_present_flag) {
buffer_delay_length_minus_1 = get_bits(&gb, 5);
skip_bits_long(&gb, 32); // num_units_in_decoding_tick
skip_bits(&gb, 10); // buffer_removal_time_length_minus_1 (5)
// frame_presentation_time_length_minus_1 (5)
}
} else
decoder_model_info_present_flag = 0;
initial_display_delay_present_flag = get_bits1(&gb);
operating_points_cnt_minus_1 = get_bits(&gb, 5);
for (int i = 0; i <= operating_points_cnt_minus_1; i++) {
int seq_level_idx, seq_tier;
skip_bits(&gb, 12); // operating_point_idc
seq_level_idx = get_bits(&gb, 5);
if (seq_level_idx > 7)
seq_tier = get_bits1(&gb);
else
seq_tier = 0;
if (decoder_model_info_present_flag) {
if (get_bits1(&gb)) { // decoder_model_present_for_this_op
skip_bits_long(&gb, buffer_delay_length_minus_1 + 1); // decoder_buffer_delay
skip_bits_long(&gb, buffer_delay_length_minus_1 + 1); // encoder_buffer_delay
skip_bits1(&gb); // low_delay_mode_flag
}
}
if (initial_display_delay_present_flag) {
if (get_bits1(&gb)) // initial_display_delay_present_for_this_op
skip_bits(&gb, 4); // initial_display_delay_minus_1
}
if (i == 0) {
seq_params->level = seq_level_idx;
seq_params->tier = seq_tier;
}
}
}
frame_width_bits_minus_1 = get_bits(&gb, 4);
frame_height_bits_minus_1 = get_bits(&gb, 4);
skip_bits(&gb, frame_width_bits_minus_1 + 1); // max_frame_width_minus_1
skip_bits(&gb, frame_height_bits_minus_1 + 1); // max_frame_height_minus_1
if (!reduced_still_picture_header) {
if (get_bits1(&gb)) // frame_id_numbers_present_flag
skip_bits(&gb, 7); // delta_frame_id_length_minus_2 (4), additional_frame_id_length_minus_1 (3)
}
skip_bits(&gb, 3); // use_128x128_superblock (1), enable_filter_intra (1), enable_intra_edge_filter (1)
if (!reduced_still_picture_header) {
int enable_order_hint, seq_force_screen_content_tools;
skip_bits(&gb, 4); // enable_interintra_compound (1), enable_masked_compound (1)
// enable_warped_motion (1), enable_dual_filter (1)
enable_order_hint = get_bits1(&gb);
if (enable_order_hint)
skip_bits(&gb, 2); // enable_jnt_comp (1), enable_ref_frame_mvs (1)
if (get_bits1(&gb)) // seq_choose_screen_content_tools
seq_force_screen_content_tools = 2;
else
seq_force_screen_content_tools = get_bits1(&gb);
if (seq_force_screen_content_tools) {
if (!get_bits1(&gb)) // seq_choose_integer_mv
skip_bits1(&gb); // seq_force_integer_mv
}
if (enable_order_hint)
skip_bits(&gb, 3); // order_hint_bits_minus_1
}
skip_bits(&gb, 3); // enable_superres (1), enable_cdef (1), enable_restoration (1)
parse_color_config(seq_params, &gb);
skip_bits1(&gb); // film_grain_params_present
if (get_bits_left(&gb))
return AVERROR_INVALIDDATA;
return 0;
}
int ff_av1_parse_seq_header(AV1SequenceParameters *seq, const uint8_t *buf, int size)
{
int64_t obu_size;
int start_pos, type, temporal_id, spatial_id;
if (size <= 0)
return AVERROR_INVALIDDATA;
while (size > 0) {
int len = parse_obu_header(buf, size, &obu_size, &start_pos,
&type, &temporal_id, &spatial_id);
if (len < 0)
return len;
switch (type) {
case AV1_OBU_SEQUENCE_HEADER:
if (!obu_size)
return AVERROR_INVALIDDATA;
return parse_sequence_header(seq, buf + start_pos, obu_size);
default:
break;
}
size -= len;
buf += len;
}
return AVERROR_INVALIDDATA;
}
int ff_isom_write_av1c(AVIOContext *pb, const uint8_t *buf, int size)
{
AVIOContext *meta_pb;
AV1SequenceParameters seq_params;
PutBitContext pbc;
uint8_t header[4], *meta;
const uint8_t *seq;
int64_t obu_size;
int start_pos, type, temporal_id, spatial_id;
int ret, nb_seq = 0, seq_size, meta_size;
if (size <= 0)
return AVERROR_INVALIDDATA;
ret = avio_open_dyn_buf(&meta_pb);
if (ret < 0)
return ret;
while (size > 0) {
int len = parse_obu_header(buf, size, &obu_size, &start_pos,
&type, &temporal_id, &spatial_id);
if (len < 0) {
ret = len;
goto fail;
}
switch (type) {
case AV1_OBU_SEQUENCE_HEADER:
nb_seq++;
if (!obu_size || nb_seq > 1) {
ret = AVERROR_INVALIDDATA;
goto fail;
}
ret = parse_sequence_header(&seq_params, buf + start_pos, obu_size);
if (ret < 0)
goto fail;
seq = buf;
seq_size = len;
break;
case AV1_OBU_METADATA:
if (!obu_size) {
ret = AVERROR_INVALIDDATA;
goto fail;
}
avio_write(meta_pb, buf, len);
break;
default:
break;
}
size -= len;
buf += len;
}
if (!nb_seq) {
ret = AVERROR_INVALIDDATA;
goto fail;
}
init_put_bits(&pbc, header, sizeof(header));
put_bits(&pbc, 1, 1); // marker
put_bits(&pbc, 7, 1); // version
put_bits(&pbc, 3, seq_params.profile);
put_bits(&pbc, 5, seq_params.level);
put_bits(&pbc, 1, seq_params.tier);
put_bits(&pbc, 1, seq_params.bitdepth > 8);
put_bits(&pbc, 1, seq_params.bitdepth == 12);
put_bits(&pbc, 1, seq_params.monochrome);
put_bits(&pbc, 1, seq_params.chroma_subsampling_x);
put_bits(&pbc, 1, seq_params.chroma_subsampling_y);
put_bits(&pbc, 2, seq_params.chroma_sample_position);
put_bits(&pbc, 8, 0); // padding
flush_put_bits(&pbc);
avio_write(pb, header, sizeof(header));
avio_write(pb, seq, seq_size);
meta_size = avio_get_dyn_buf(meta_pb, &meta);
if (meta_size)
avio_write(pb, meta, meta_size);
fail:
ffio_free_dyn_buf(&meta_pb);
return ret;
}
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