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ffmpeg/libavformat/avc.c
James Almer 53c8d417ed avformat: split off generic NAL function helpers into their own file 
Signed-off-by: James Almer <jamrial@gmail.com>
2024-06-20 08:57:45 -03:00

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/*
* AVC helper functions for muxers
* Copyright (c) 2006 Baptiste Coudurier <baptiste.coudurier@smartjog.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/intreadwrite.h"
#include "libavutil/mem.h"
#include "libavcodec/h264.h"
#include "libavcodec/get_bits.h"
#include "avio.h"
#include "avc.h"
#include "avio_internal.h"
#include "nal.h"
int ff_isom_write_avcc(AVIOContext *pb, const uint8_t *data, int len)
{
AVIOContext *sps_pb = NULL, *pps_pb = NULL, *sps_ext_pb = NULL;
uint8_t *buf, *end, *start;
uint8_t *sps, *pps, *sps_ext;
uint32_t sps_size = 0, pps_size = 0, sps_ext_size = 0;
int ret, nb_sps = 0, nb_pps = 0, nb_sps_ext = 0;
if (len <= 6)
return AVERROR_INVALIDDATA;
/* check for H.264 start code */
if (AV_RB32(data) != 0x00000001 &&
AV_RB24(data) != 0x000001) {
avio_write(pb, data, len);
return 0;
}
ret = ff_nal_parse_units_buf(data, &buf, &len);
if (ret < 0)
return ret;
start = buf;
end = buf + len;
ret = avio_open_dyn_buf(&sps_pb);
if (ret < 0)
goto fail;
ret = avio_open_dyn_buf(&pps_pb);
if (ret < 0)
goto fail;
ret = avio_open_dyn_buf(&sps_ext_pb);
if (ret < 0)
goto fail;
/* look for sps and pps */
while (end - buf > 4) {
uint32_t size;
uint8_t nal_type;
size = FFMIN(AV_RB32(buf), end - buf - 4);
buf += 4;
nal_type = buf[0] & 0x1f;
if (nal_type == 7) { /* SPS */
nb_sps++;
if (size > UINT16_MAX || nb_sps >= H264_MAX_SPS_COUNT) {
ret = AVERROR_INVALIDDATA;
goto fail;
}
avio_wb16(sps_pb, size);
avio_write(sps_pb, buf, size);
} else if (nal_type == 8) { /* PPS */
nb_pps++;
if (size > UINT16_MAX || nb_pps >= H264_MAX_PPS_COUNT) {
ret = AVERROR_INVALIDDATA;
goto fail;
}
avio_wb16(pps_pb, size);
avio_write(pps_pb, buf, size);
} else if (nal_type == 13) { /* SPS_EXT */
nb_sps_ext++;
if (size > UINT16_MAX || nb_sps_ext >= 256) {
ret = AVERROR_INVALIDDATA;
goto fail;
}
avio_wb16(sps_ext_pb, size);
avio_write(sps_ext_pb, buf, size);
}
buf += size;
}
sps_size = avio_get_dyn_buf(sps_pb, &sps);
pps_size = avio_get_dyn_buf(pps_pb, &pps);
sps_ext_size = avio_get_dyn_buf(sps_ext_pb, &sps_ext);
if (sps_size < 6 || !pps_size) {
ret = AVERROR_INVALIDDATA;
goto fail;
}
avio_w8(pb, 1); /* version */
avio_w8(pb, sps[3]); /* profile */
avio_w8(pb, sps[4]); /* profile compat */
avio_w8(pb, sps[5]); /* level */
avio_w8(pb, 0xff); /* 6 bits reserved (111111) + 2 bits nal size length - 1 (11) */
avio_w8(pb, 0xe0 | nb_sps); /* 3 bits reserved (111) + 5 bits number of sps */
avio_write(pb, sps, sps_size);
avio_w8(pb, nb_pps); /* number of pps */
avio_write(pb, pps, pps_size);
if (sps[3] != 66 && sps[3] != 77 && sps[3] != 88) {
H264SPS seq;
ret = ff_avc_decode_sps(&seq, sps + 3, sps_size - 3);
if (ret < 0)
goto fail;
avio_w8(pb, 0xfc | seq.chroma_format_idc); /* 6 bits reserved (111111) + chroma_format_idc */
avio_w8(pb, 0xf8 | (seq.bit_depth_luma - 8)); /* 5 bits reserved (11111) + bit_depth_luma_minus8 */
avio_w8(pb, 0xf8 | (seq.bit_depth_chroma - 8)); /* 5 bits reserved (11111) + bit_depth_chroma_minus8 */
avio_w8(pb, nb_sps_ext); /* number of sps ext */
if (nb_sps_ext)
avio_write(pb, sps_ext, sps_ext_size);
}
fail:
ffio_free_dyn_buf(&sps_pb);
ffio_free_dyn_buf(&pps_pb);
ffio_free_dyn_buf(&sps_ext_pb);
av_free(start);
return ret;
}
int ff_avc_write_annexb_extradata(const uint8_t *in, uint8_t **buf, int *size)
{
uint16_t sps_size, pps_size;
uint8_t *out;
int out_size;
*buf = NULL;
if (*size >= 4 && (AV_RB32(in) == 0x00000001 || AV_RB24(in) == 0x000001))
return 0;
if (*size < 11 || in[0] != 1)
return AVERROR_INVALIDDATA;
sps_size = AV_RB16(&in[6]);
if (11 + sps_size > *size)
return AVERROR_INVALIDDATA;
pps_size = AV_RB16(&in[9 + sps_size]);
if (11 + sps_size + pps_size > *size)
return AVERROR_INVALIDDATA;
out_size = 8 + sps_size + pps_size;
out = av_mallocz(out_size + AV_INPUT_BUFFER_PADDING_SIZE);
if (!out)
return AVERROR(ENOMEM);
AV_WB32(&out[0], 0x00000001);
memcpy(out + 4, &in[8], sps_size);
AV_WB32(&out[4 + sps_size], 0x00000001);
memcpy(out + 8 + sps_size, &in[11 + sps_size], pps_size);
*buf = out;
*size = out_size;
return 0;
}
static const AVRational avc_sample_aspect_ratio[17] = {
{ 0, 1 },
{ 1, 1 },
{ 12, 11 },
{ 10, 11 },
{ 16, 11 },
{ 40, 33 },
{ 24, 11 },
{ 20, 11 },
{ 32, 11 },
{ 80, 33 },
{ 18, 11 },
{ 15, 11 },
{ 64, 33 },
{ 160, 99 },
{ 4, 3 },
{ 3, 2 },
{ 2, 1 },
};
static inline int get_ue_golomb(GetBitContext *gb) {
int i;
for (i = 0; i < 32 && !get_bits1(gb); i++)
;
return get_bitsz(gb, i) + (1 << i) - 1;
}
static inline int get_se_golomb(GetBitContext *gb) {
int v = get_ue_golomb(gb) + 1;
int sign = -(v & 1);
return ((v >> 1) ^ sign) - sign;
}
int ff_avc_decode_sps(H264SPS *sps, const uint8_t *buf, int buf_size)
{
int i, j, ret, rbsp_size, aspect_ratio_idc, pic_order_cnt_type;
int num_ref_frames_in_pic_order_cnt_cycle;
int delta_scale, lastScale = 8, nextScale = 8;
int sizeOfScalingList;
GetBitContext gb;
uint8_t *rbsp_buf;
rbsp_buf = ff_nal_unit_extract_rbsp(buf, buf_size, &rbsp_size, 0);
if (!rbsp_buf)
return AVERROR(ENOMEM);
ret = init_get_bits8(&gb, rbsp_buf, rbsp_size);
if (ret < 0)
goto end;
memset(sps, 0, sizeof(*sps));
sps->profile_idc = get_bits(&gb, 8);
sps->constraint_set_flags |= get_bits1(&gb) << 0; // constraint_set0_flag
sps->constraint_set_flags |= get_bits1(&gb) << 1; // constraint_set1_flag
sps->constraint_set_flags |= get_bits1(&gb) << 2; // constraint_set2_flag
sps->constraint_set_flags |= get_bits1(&gb) << 3; // constraint_set3_flag
sps->constraint_set_flags |= get_bits1(&gb) << 4; // constraint_set4_flag
sps->constraint_set_flags |= get_bits1(&gb) << 5; // constraint_set5_flag
skip_bits(&gb, 2); // reserved_zero_2bits
sps->level_idc = get_bits(&gb, 8);
sps->id = get_ue_golomb(&gb);
if (sps->profile_idc == 100 || sps->profile_idc == 110 ||
sps->profile_idc == 122 || sps->profile_idc == 244 || sps->profile_idc == 44 ||
sps->profile_idc == 83 || sps->profile_idc == 86 || sps->profile_idc == 118 ||
sps->profile_idc == 128 || sps->profile_idc == 138 || sps->profile_idc == 139 ||
sps->profile_idc == 134) {
sps->chroma_format_idc = get_ue_golomb(&gb); // chroma_format_idc
if (sps->chroma_format_idc == 3) {
skip_bits1(&gb); // separate_colour_plane_flag
}
sps->bit_depth_luma = get_ue_golomb(&gb) + 8;
sps->bit_depth_chroma = get_ue_golomb(&gb) + 8;
skip_bits1(&gb); // qpprime_y_zero_transform_bypass_flag
if (get_bits1(&gb)) { // seq_scaling_matrix_present_flag
for (i = 0; i < ((sps->chroma_format_idc != 3) ? 8 : 12); i++) {
if (!get_bits1(&gb)) // seq_scaling_list_present_flag
continue;
lastScale = 8;
nextScale = 8;
sizeOfScalingList = i < 6 ? 16 : 64;
for (j = 0; j < sizeOfScalingList; j++) {
if (nextScale != 0) {
delta_scale = get_se_golomb(&gb);
nextScale = (lastScale + delta_scale) & 0xff;
}
lastScale = nextScale == 0 ? lastScale : nextScale;
}
}
}
} else {
sps->chroma_format_idc = 1;
sps->bit_depth_luma = 8;
sps->bit_depth_chroma = 8;
}
get_ue_golomb(&gb); // log2_max_frame_num_minus4
pic_order_cnt_type = get_ue_golomb(&gb);
if (pic_order_cnt_type == 0) {
get_ue_golomb(&gb); // log2_max_pic_order_cnt_lsb_minus4
} else if (pic_order_cnt_type == 1) {
skip_bits1(&gb); // delta_pic_order_always_zero
get_se_golomb(&gb); // offset_for_non_ref_pic
get_se_golomb(&gb); // offset_for_top_to_bottom_field
num_ref_frames_in_pic_order_cnt_cycle = get_ue_golomb(&gb);
for (i = 0; i < num_ref_frames_in_pic_order_cnt_cycle; i++)
get_se_golomb(&gb); // offset_for_ref_frame
}
get_ue_golomb(&gb); // max_num_ref_frames
skip_bits1(&gb); // gaps_in_frame_num_value_allowed_flag
get_ue_golomb(&gb); // pic_width_in_mbs_minus1
get_ue_golomb(&gb); // pic_height_in_map_units_minus1
sps->frame_mbs_only_flag = get_bits1(&gb);
if (!sps->frame_mbs_only_flag)
skip_bits1(&gb); // mb_adaptive_frame_field_flag
skip_bits1(&gb); // direct_8x8_inference_flag
if (get_bits1(&gb)) { // frame_cropping_flag
get_ue_golomb(&gb); // frame_crop_left_offset
get_ue_golomb(&gb); // frame_crop_right_offset
get_ue_golomb(&gb); // frame_crop_top_offset
get_ue_golomb(&gb); // frame_crop_bottom_offset
}
if (get_bits1(&gb)) { // vui_parameters_present_flag
if (get_bits1(&gb)) { // aspect_ratio_info_present_flag
aspect_ratio_idc = get_bits(&gb, 8);
if (aspect_ratio_idc == 0xff) {
sps->sar.num = get_bits(&gb, 16);
sps->sar.den = get_bits(&gb, 16);
} else if (aspect_ratio_idc < FF_ARRAY_ELEMS(avc_sample_aspect_ratio)) {
sps->sar = avc_sample_aspect_ratio[aspect_ratio_idc];
}
}
}
if (!sps->sar.den) {
sps->sar.num = 1;
sps->sar.den = 1;
}
ret = 0;
end:
av_free(rbsp_buf);
return ret;
}
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