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FFmpeg/libavformat/rtpdec_h264.c

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/*
* RTP H264 Protocol (RFC3984)
* Copyright (c) 2006 Ryan Martell
*
* This file is part of Libav.
*
* Libav 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.
*
* Libav 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 Libav; if not, write to the Free Software
* Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA
*/
/**
* @file
* @brief H.264 / RTP Code (RFC3984)
* @author Ryan Martell <rdm4@martellventures.com>
*
* @note Notes:
* Notes:
* This currently supports packetization mode:
* Single Nal Unit Mode (0), or
* Non-Interleaved Mode (1). It currently does not support
* Interleaved Mode (2). (This requires implementing STAP-B, MTAP16, MTAP24,
* FU-B packet types)
*/
#include "libavutil/base64.h"
#include "libavutil/avstring.h"
#include "libavcodec/get_bits.h"
#include "avformat.h"
#include "network.h"
#include <assert.h>
#include "rtpdec.h"
#include "rtpdec_formats.h"
struct PayloadContext {
// sdp setup parameters
uint8_t profile_idc;
uint8_t profile_iop;
uint8_t level_idc;
int packetization_mode;
#ifdef DEBUG
int packet_types_received[32];
#endif
};
#ifdef DEBUG
#define COUNT_NAL_TYPE(data, nal) data->packet_types_received[(nal) & 0x1f]++
#else
#define COUNT_NAL_TYPE(data, nal) do { } while (0)
#endif
static const uint8_t start_sequence[] = { 0, 0, 0, 1 };
static int sdp_parse_fmtp_config_h264(AVStream *stream,
PayloadContext *h264_data,
char *attr, char *value)
{
AVCodecContext *codec = stream->codec;
assert(codec->codec_id == AV_CODEC_ID_H264);
assert(h264_data != NULL);
if (!strcmp(attr, "packetization-mode")) {
av_log(codec, AV_LOG_DEBUG, "RTP Packetization Mode: %d\n", atoi(value));
h264_data->packetization_mode = atoi(value);
/*
* Packetization Mode:
* 0 or not present: Single NAL mode (Only nals from 1-23 are allowed)
* 1: Non-interleaved Mode: 1-23, 24 (STAP-A), 28 (FU-A) are allowed.
* 2: Interleaved Mode: 25 (STAP-B), 26 (MTAP16), 27 (MTAP24), 28 (FU-A),
* and 29 (FU-B) are allowed.
*/
if (h264_data->packetization_mode > 1)
av_log(codec, AV_LOG_ERROR,
"Interleaved RTP mode is not supported yet.\n");
} else if (!strcmp(attr, "profile-level-id")) {
if (strlen(value) == 6) {
char buffer[3];
// 6 characters=3 bytes, in hex.
uint8_t profile_idc;
uint8_t profile_iop;
uint8_t level_idc;
buffer[0] = value[0];
buffer[1] = value[1];
buffer[2] = '\0';
profile_idc = strtol(buffer, NULL, 16);
buffer[0] = value[2];
buffer[1] = value[3];
profile_iop = strtol(buffer, NULL, 16);
buffer[0] = value[4];
buffer[1] = value[5];
level_idc = strtol(buffer, NULL, 16);
av_log(codec, AV_LOG_DEBUG,
"RTP Profile IDC: %x Profile IOP: %x Level: %x\n",
profile_idc, profile_iop, level_idc);
h264_data->profile_idc = profile_idc;
h264_data->profile_iop = profile_iop;
h264_data->level_idc = level_idc;
}
} else if (!strcmp(attr, "sprop-parameter-sets")) {
codec->extradata_size = 0;
av_freep(&codec->extradata);
while (*value) {
char base64packet[1024];
uint8_t decoded_packet[1024];
int packet_size;
char *dst = base64packet;
while (*value && *value != ','
&& (dst - base64packet) < sizeof(base64packet) - 1) {
*dst++ = *value++;
}
*dst++ = '\0';
if (*value == ',')
value++;
packet_size = av_base64_decode(decoded_packet, base64packet,
sizeof(decoded_packet));
if (packet_size > 0) {
uint8_t *dest = av_malloc(packet_size + sizeof(start_sequence) +
codec->extradata_size +
FF_INPUT_BUFFER_PADDING_SIZE);
if (!dest) {
av_log(codec, AV_LOG_ERROR,
"Unable to allocate memory for extradata!\n");
return AVERROR(ENOMEM);
}
if (codec->extradata_size) {
memcpy(dest, codec->extradata, codec->extradata_size);
av_free(codec->extradata);
}
memcpy(dest + codec->extradata_size, start_sequence,
sizeof(start_sequence));
memcpy(dest + codec->extradata_size + sizeof(start_sequence),
decoded_packet, packet_size);
memset(dest + codec->extradata_size + sizeof(start_sequence) +
packet_size, 0, FF_INPUT_BUFFER_PADDING_SIZE);
codec->extradata = dest;
codec->extradata_size += sizeof(start_sequence) + packet_size;
}
}
av_log(codec, AV_LOG_DEBUG, "Extradata set to %p (size: %d)!\n",
codec->extradata, codec->extradata_size);
}
return 0;
}
// return 0 on packet, no more left, 1 on packet, 1 on partial packet
static int h264_handle_packet(AVFormatContext *ctx, PayloadContext *data,
AVStream *st, AVPacket *pkt, uint32_t *timestamp,
const uint8_t *buf, int len, int flags)
{
uint8_t nal;
uint8_t type;
int result = 0;
if (!len) {
av_log(ctx, AV_LOG_ERROR, "Empty H264 RTP packet\n");
return AVERROR_INVALIDDATA;
}
nal = buf[0];
type = nal & 0x1f;
assert(data);
assert(buf);
/* Simplify the case (these are all the nal types used internally by
* the h264 codec). */
if (type >= 1 && type <= 23)
type = 1;
switch (type) {
case 0: // undefined, but pass them through
case 1:
av_new_packet(pkt, len + sizeof(start_sequence));
memcpy(pkt->data, start_sequence, sizeof(start_sequence));
memcpy(pkt->data + sizeof(start_sequence), buf, len);
COUNT_NAL_TYPE(data, nal);
break;
case 24: // STAP-A (one packet, multiple nals)
// consume the STAP-A NAL
buf++;
len--;
// first we are going to figure out the total size
{
int pass = 0;
int total_length = 0;
uint8_t *dst = NULL;
for (pass = 0; pass < 2; pass++) {
const uint8_t *src = buf;
int src_len = len;
while (src_len > 2) {
uint16_t nal_size = AV_RB16(src);
// consume the length of the aggregate
src += 2;
src_len -= 2;
if (nal_size <= src_len) {
if (pass == 0) {
// counting
total_length += sizeof(start_sequence) + nal_size;
} else {
// copying
assert(dst);
memcpy(dst, start_sequence, sizeof(start_sequence));
dst += sizeof(start_sequence);
memcpy(dst, src, nal_size);
COUNT_NAL_TYPE(data, *src);
dst += nal_size;
}
} else {
av_log(ctx, AV_LOG_ERROR,
"nal size exceeds length: %d %d\n", nal_size, src_len);
}
// eat what we handled
src += nal_size;
src_len -= nal_size;
if (src_len < 0)
av_log(ctx, AV_LOG_ERROR,
"Consumed more bytes than we got! (%d)\n", src_len);
}
if (pass == 0) {
/* now we know the total size of the packet (with the
* start sequences added) */
av_new_packet(pkt, total_length);
dst = pkt->data;
} else {
assert(dst - pkt->data == total_length);
}
}
}
break;
case 25: // STAP-B
case 26: // MTAP-16
case 27: // MTAP-24
case 29: // FU-B
av_log(ctx, AV_LOG_ERROR,
"Unhandled type (%d) (See RFC for implementation details\n",
type);
result = AVERROR(ENOSYS);
break;
case 28: // FU-A (fragmented nal)
buf++;
len--; // skip the fu_indicator
if (len > 1) {
// these are the same as above, we just redo them here for clarity
uint8_t fu_indicator = nal;
uint8_t fu_header = *buf;
uint8_t start_bit = fu_header >> 7;
uint8_t av_unused end_bit = (fu_header & 0x40) >> 6;
uint8_t nal_type = fu_header & 0x1f;
uint8_t reconstructed_nal;
// Reconstruct this packet's true nal; only the data follows.
/* The original nal forbidden bit and NRI are stored in this
* packet's nal. */
reconstructed_nal = fu_indicator & 0xe0;
reconstructed_nal |= nal_type;
// skip the fu_header
buf++;
len--;
if (start_bit)
COUNT_NAL_TYPE(data, nal_type);
if (start_bit) {
/* copy in the start sequence, and the reconstructed nal */
av_new_packet(pkt, sizeof(start_sequence) + sizeof(nal) + len);
memcpy(pkt->data, start_sequence, sizeof(start_sequence));
pkt->data[sizeof(start_sequence)] = reconstructed_nal;
memcpy(pkt->data + sizeof(start_sequence) + sizeof(nal), buf, len);
} else {
av_new_packet(pkt, len);
memcpy(pkt->data, buf, len);
}
} else {
av_log(ctx, AV_LOG_ERROR, "Too short data for FU-A H264 RTP packet\n");
result = AVERROR_INVALIDDATA;
}
break;
case 30: // undefined
case 31: // undefined
default:
av_log(ctx, AV_LOG_ERROR, "Undefined type (%d)\n", type);
result = AVERROR_INVALIDDATA;
break;
}
pkt->stream_index = st->index;
return result;
}
static PayloadContext *h264_new_context(void)
{
return av_mallocz(sizeof(PayloadContext) + FF_INPUT_BUFFER_PADDING_SIZE);
}
static void h264_free_context(PayloadContext *data)
{
#ifdef DEBUG
int ii;
for (ii = 0; ii < 32; ii++) {
if (data->packet_types_received[ii])
av_log(NULL, AV_LOG_DEBUG, "Received %d packets of type %d\n",
data->packet_types_received[ii], ii);
}
#endif
av_free(data);
}
static int parse_h264_sdp_line(AVFormatContext *s, int st_index,
PayloadContext *h264_data, const char *line)
{
AVStream *stream;
AVCodecContext *codec;
const char *p = line;
if (st_index < 0)
return 0;
stream = s->streams[st_index];
codec = stream->codec;
if (av_strstart(p, "framesize:", &p)) {
char buf1[50];
char *dst = buf1;
// remove the protocol identifier
while (*p && *p == ' ')
p++; // strip spaces.
while (*p && *p != ' ')
p++; // eat protocol identifier
while (*p && *p == ' ')
p++; // strip trailing spaces.
while (*p && *p != '-' && (dst - buf1) < sizeof(buf1) - 1)
*dst++ = *p++;
*dst = '\0';
// a='framesize:96 320-240'
// set our parameters
codec->width = atoi(buf1);
codec->height = atoi(p + 1); // skip the -
} else if (av_strstart(p, "fmtp:", &p)) {
return ff_parse_fmtp(stream, h264_data, p, sdp_parse_fmtp_config_h264);
} else if (av_strstart(p, "cliprect:", &p)) {
// could use this if we wanted.
}
return 0;
}
RTPDynamicProtocolHandler ff_h264_dynamic_handler = {
.enc_name = "H264",
.codec_type = AVMEDIA_TYPE_VIDEO,
.codec_id = AV_CODEC_ID_H264,
.parse_sdp_a_line = parse_h264_sdp_line,
.alloc = h264_new_context,
.free = h264_free_context,
.parse_packet = h264_handle_packet
};