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ffmpeg/libavformat/avc.c
Andreas Rheinhardt a0b6df0a39 avformat/avc, mxfenc: Avoid allocation of H264 SPS structure, fix memleak 
Up until now, ff_avc_decode_sps would parse a SPS and return some
properties from it in a freshly allocated structure. Yet said structure
is very small and completely internal to libavformat, so there is no
reason to use the heap for it. This commit therefore changes the
function to return an int and to modify a caller-provided structure.
This will also allow ff_avc_decode_sps to return better error codes in
the future.

It also fixes a memleak in mxfenc: If a packet contained multiple SPS,
only the SPS structure belonging to the last SPS would be freed, the
other ones would leak when the pointer is overwritten to point to the
new SPS structure. Of course, without allocations there are no leaks.
This is Coverity issue #1445194.

Furthermore, the SPS structure has been renamed from
H264SequenceParameterSet to H264SPS in order to avoid overlong lines.

Reviewed-by: Tomas Härdin <tjoppen@acc.umu.se>
Signed-off-by: Andreas Rheinhardt <andreas.rheinhardt@gmail.com>
2020-06-26 12:13:43 +02:00

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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 "libavcodec/h264.h"
#include "libavcodec/get_bits.h"
#include "avformat.h"
#include "avio.h"
#include "avc.h"
#include "avio_internal.h"
static const uint8_t *avc_find_startcode_internal(const uint8_t *p, const uint8_t *end)
{
const uint8_t *a = p + 4 - ((intptr_t)p & 3);
for (end -= 3; p < a && p < end; p++) {
if (p[0] == 0 && p[1] == 0 && p[2] == 1)
return p;
}
for (end -= 3; p < end; p += 4) {
uint32_t x = *(const uint32_t*)p;
// if ((x - 0x01000100) & (~x) & 0x80008000) // little endian
// if ((x - 0x00010001) & (~x) & 0x00800080) // big endian
if ((x - 0x01010101) & (~x) & 0x80808080) { // generic
if (p[1] == 0) {
if (p[0] == 0 && p[2] == 1)
return p;
if (p[2] == 0 && p[3] == 1)
return p+1;
}
if (p[3] == 0) {
if (p[2] == 0 && p[4] == 1)
return p+2;
if (p[4] == 0 && p[5] == 1)
return p+3;
}
}
}
for (end += 3; p < end; p++) {
if (p[0] == 0 && p[1] == 0 && p[2] == 1)
return p;
}
return end + 3;
}
const uint8_t *ff_avc_find_startcode(const uint8_t *p, const uint8_t *end){
const uint8_t *out = avc_find_startcode_internal(p, end);
if(p<out && out<end && !out[-1]) out--;
return out;
}
int ff_avc_parse_nal_units(AVIOContext *pb, const uint8_t *buf_in, int size)
{
const uint8_t *p = buf_in;
const uint8_t *end = p + size;
const uint8_t *nal_start, *nal_end;
size = 0;
nal_start = ff_avc_find_startcode(p, end);
for (;;) {
while (nal_start < end && !*(nal_start++));
if (nal_start == end)
break;
nal_end = ff_avc_find_startcode(nal_start, end);
avio_wb32(pb, nal_end - nal_start);
avio_write(pb, nal_start, nal_end - nal_start);
size += 4 + nal_end - nal_start;
nal_start = nal_end;
}
return size;
}
int ff_avc_parse_nal_units_buf(const uint8_t *buf_in, uint8_t **buf, int *size)
{
AVIOContext *pb;
int ret = avio_open_dyn_buf(&pb);
if(ret < 0)
return ret;
ff_avc_parse_nal_units(pb, buf_in, *size);
*size = avio_close_dyn_buf(pb, buf);
return 0;
}
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_avc_parse_nal_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;
}
const uint8_t *ff_avc_mp4_find_startcode(const uint8_t *start,
const uint8_t *end,
int nal_length_size)
{
unsigned int res = 0;
if (end - start < nal_length_size)
return NULL;
while (nal_length_size--)
res = (res << 8) | *start++;
if (res > end - start)
return NULL;
return start + res;
}
uint8_t *ff_nal_unit_extract_rbsp(const uint8_t *src, uint32_t src_len,
uint32_t *dst_len, int header_len)
{
uint8_t *dst;
uint32_t i, len;
dst = av_malloc(src_len + AV_INPUT_BUFFER_PADDING_SIZE);
if (!dst)
return NULL;
/* NAL unit header */
i = len = 0;
while (i < header_len && i < src_len)
dst[len++] = src[i++];
while (i + 2 < src_len)
if (!src[i] && !src[i + 1] && src[i + 2] == 3) {
dst[len++] = src[i++];
dst[len++] = src[i++];
i++; // remove emulation_prevention_three_byte
} else
dst[len++] = src[i++];
while (i < src_len)
dst[len++] = src[i++];
memset(dst + len, 0, AV_INPUT_BUFFER_PADDING_SIZE);
*dst_len = len;
return dst;
}
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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