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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 "avformat.h"
#include "avio.h"
#include "avc.h"
static const uint8_t *ff_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= ff_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);
av_freep(buf);
*size = avio_close_dyn_buf(pb, buf);
return 0;
}
int ff_isom_write_avcc(AVIOContext *pb, const uint8_t *data, int len)
{
uint8_t *buf = NULL, *end, *start = NULL;
uint8_t *sps = NULL, *pps = NULL;
uint32_t sps_size = 0, pps_size = 0;
int ret;
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;
/* 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 */
sps = buf;
sps_size = size;
} else if (nal_type == 8) { /* PPS */
pps = buf;
pps_size = size;
}
buf += size;
}
if (!sps || !pps || sps_size < 4 || sps_size > UINT16_MAX || pps_size > UINT16_MAX) {
ret = AVERROR_INVALIDDATA;
goto fail;
}
avio_w8(pb, 1); /* version */
avio_w8(pb, sps[1]); /* profile */
avio_w8(pb, sps[2]); /* profile compat */
avio_w8(pb, sps[3]); /* level */
avio_w8(pb, 0xff); /* 6 bits reserved (111111) + 2 bits nal size length - 1 (11) */
avio_w8(pb, 0xe1); /* 3 bits reserved (111) + 5 bits number of sps (00001) */
avio_wb16(pb, sps_size);
avio_write(pb, sps, sps_size);
avio_w8(pb, 1); /* number of pps */
avio_wb16(pb, pps_size);
avio_write(pb, pps, pps_size);
fail:
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;
}
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