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FFmpeg/libavformat/av1.c
Andreas Rheinhardt a3e43e0cf3 avformat/av1: Avoid allocation + copying when filtering OBUs 
Certain types of OBUs are stripped away before muxing into Matroska and
ISOBMFF; there are two functions to do this: One that outputs by
directly writing in an AVIOContext and one that returns a freshly
allocated buffer with the units not stripped away copied into it.

The latter option is bad for performance, especially when the input
does already not contain any of the units intended to be stripped away
(this covers typical remuxing scenarios). Therefore this commit changes
this by avoiding allocating and copying when possible; it is possible if
the OBUs to be retained are consecutively in the input buffer (without
an OBU to be discarded between them). In this case, the caller receives
the offset as well as the length of the part of the buffer that contains
the units to be kept. This also avoids copying when e.g. the only unit
to be discarded is a temporal delimiter at the front.

For a 22.7mb/s file with average framesize 113 kB this improved the time
for the calls to ff_av1_filter_obus_buf() when writing Matroska from
313319 decicycles to 2368 decicycles; for another file with 1.5mb/s
(average framesize 7.3 kB) it improved from 34539 decicycles to 1922
decicyles. For these files the only units that needed to be stripped
away were temporal unit delimiters at the front.

Signed-off-by: Andreas Rheinhardt <andreas.rheinhardt@gmail.com>
Signed-off-by: James Almer <jamrial@gmail.com>
2020-01-26 12:41:32 -03:00

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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 *seq_pb = NULL, *meta_pb = NULL;
AV1SequenceParameters seq_params;
PutBitContext pbc;
uint8_t header[4];
uint8_t *seq, *meta;
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(&seq_pb);
if (ret < 0)
return ret;
ret = avio_open_dyn_buf(&meta_pb);
if (ret < 0)
goto fail;
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;
avio_write(seq_pb, buf, 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;
}
seq_size = avio_get_dyn_buf(seq_pb, &seq);
if (!seq_size) {
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(&seq_pb);
ffio_free_dyn_buf(&meta_pb);
return ret;
}
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