libavformat/rtpdec_mpeg4.c - third_party/ffmpeg - Git at Google

 /*
  * Common code for the RTP depacketization of MPEG-4 formats.
  * Copyright (c) 2010 Fabrice Bellard
  *                    Romain Degez
  *
  * 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
  */

 /**
  * @file
  * @brief MPEG4 / RTP Code
  * @author Fabrice Bellard
  * @author Romain Degez
  */

 #include "rtpdec_formats.h"
 #include "internal.h"
 #include "libavutil/avstring.h"
 #include "libavcodec/get_bits.h"

 /** Structure listing useful vars to parse RTP packet payload */
 struct PayloadContext {
     int sizelength;
     int indexlength;
     int indexdeltalength;
     int profile_level_id;
     int streamtype;
     int objecttype;
     char *mode;

     /** mpeg 4 AU headers */
     struct AUHeaders {
         int size;
         int index;
         int cts_flag;
         int cts;
         int dts_flag;
         int dts;
         int rap_flag;
         int streamstate;
     } *au_headers;
     int au_headers_allocated;
     int nb_au_headers;
     int au_headers_length_bytes;
     int cur_au_index;

     uint8_t buf[RTP_MAX_PACKET_LENGTH];
     int buf_pos, buf_size;
 };

 typedef struct {
     const char *str;
     uint16_t    type;
     uint32_t    offset;
 } AttrNameMap;

 /* All known fmtp parameters and the corresponding RTPAttrTypeEnum */
 #define ATTR_NAME_TYPE_INT 0
 #define ATTR_NAME_TYPE_STR 1
 static const AttrNameMap attr_names[] = {
     { "SizeLength",       ATTR_NAME_TYPE_INT,
       offsetof(PayloadContext, sizelength) },
     { "IndexLength",      ATTR_NAME_TYPE_INT,
       offsetof(PayloadContext, indexlength) },
     { "IndexDeltaLength", ATTR_NAME_TYPE_INT,
       offsetof(PayloadContext, indexdeltalength) },
     { "profile-level-id", ATTR_NAME_TYPE_INT,
       offsetof(PayloadContext, profile_level_id) },
     { "StreamType",       ATTR_NAME_TYPE_INT,
       offsetof(PayloadContext, streamtype) },
     { "mode",             ATTR_NAME_TYPE_STR,
       offsetof(PayloadContext, mode) },
     { NULL, -1, -1 },
 };

 static PayloadContext *new_context(void)
 {
     return av_mallocz(sizeof(PayloadContext));
 }

 static void free_context(PayloadContext *data)
 {
     av_free(data->au_headers);
     av_free(data->mode);
     av_free(data);
 }

 static int parse_fmtp_config(AVCodecContext *codec, char *value)
 {
     /* decode the hexa encoded parameter */
     int len = ff_hex_to_data(NULL, value);
     av_free(codec->extradata);
     codec->extradata = av_mallocz(len + FF_INPUT_BUFFER_PADDING_SIZE);
     if (!codec->extradata)
         return AVERROR(ENOMEM);
     codec->extradata_size = len;
     ff_hex_to_data(codec->extradata, value);
     return 0;
 }

 static int rtp_parse_mp4_au(PayloadContext *data, const uint8_t *buf, int len)
 {
     int au_headers_length, au_header_size, i;
     GetBitContext getbitcontext;

     if (len < 2)
         return AVERROR_INVALIDDATA;

     /* decode the first 2 bytes where the AUHeader sections are stored
        length in bits */
     au_headers_length = AV_RB16(buf);

     if (au_headers_length > RTP_MAX_PACKET_LENGTH)
       return -1;

     data->au_headers_length_bytes = (au_headers_length + 7) / 8;

     /* skip AU headers length section (2 bytes) */
     buf += 2;
     len -= 2;

     if (len < data->au_headers_length_bytes)
         return AVERROR_INVALIDDATA;

     init_get_bits(&getbitcontext, buf, data->au_headers_length_bytes * 8);

     /* XXX: Wrong if optional additional sections are present (cts, dts etc...) */
     au_header_size = data->sizelength + data->indexlength;
     if (au_header_size <= 0 || (au_headers_length % au_header_size != 0))
         return -1;

     data->nb_au_headers = au_headers_length / au_header_size;
     if (!data->au_headers || data->au_headers_allocated < data->nb_au_headers) {
         av_free(data->au_headers);
         data->au_headers = av_malloc(sizeof(struct AUHeaders) * data->nb_au_headers);
         if (!data->au_headers)
             return AVERROR(ENOMEM);
         data->au_headers_allocated = data->nb_au_headers;
     }

     for (i = 0; i < data->nb_au_headers; ++i) {
         data->au_headers[i].size  = get_bits_long(&getbitcontext, data->sizelength);
         data->au_headers[i].index = get_bits_long(&getbitcontext, data->indexlength);
     }

     return 0;
 }


 /* Follows RFC 3640 */
 static int aac_parse_packet(AVFormatContext *ctx, PayloadContext *data,
                             AVStream *st, AVPacket *pkt, uint32_t *timestamp,
                             const uint8_t *buf, int len, uint16_t seq,
                             int flags)
 {
     int ret;

     if (!buf) {
         if (data->cur_au_index > data->nb_au_headers)
             return AVERROR_INVALIDDATA;
         if (data->buf_size - data->buf_pos < data->au_headers[data->cur_au_index].size)
             return AVERROR_INVALIDDATA;
         if ((ret = av_new_packet(pkt, data->au_headers[data->cur_au_index].size)) < 0)
             return ret;
         memcpy(pkt->data, &data->buf[data->buf_pos], data->au_headers[data->cur_au_index].size);
         data->buf_pos += data->au_headers[data->cur_au_index].size;
         pkt->stream_index = st->index;
         data->cur_au_index++;
         return data->cur_au_index < data->nb_au_headers;
     }

     if (rtp_parse_mp4_au(data, buf, len))
         return -1;

     buf += data->au_headers_length_bytes + 2;
     len -= data->au_headers_length_bytes + 2;

     if (len < data->au_headers[0].size)
         return AVERROR_INVALIDDATA;
     if ((ret = av_new_packet(pkt, data->au_headers[0].size)) < 0)
         return ret;
     memcpy(pkt->data, buf, data->au_headers[0].size);
     len -= data->au_headers[0].size;
     buf += data->au_headers[0].size;
     pkt->stream_index = st->index;

     if (len > 0 && data->nb_au_headers > 1) {
         data->buf_size = FFMIN(len, sizeof(data->buf));
         memcpy(data->buf, buf, data->buf_size);
         data->cur_au_index = 1;
         data->buf_pos = 0;
         return 1;
     }

     return 0;
 }

 static int parse_fmtp(AVStream *stream, PayloadContext *data,
                       char *attr, char *value)
 {
     AVCodecContext *codec = stream->codec;
     int res, i;

     if (!strcmp(attr, "config")) {
         res = parse_fmtp_config(codec, value);

         if (res < 0)
             return res;
     }

     if (codec->codec_id == AV_CODEC_ID_AAC) {
         /* Looking for a known attribute */
         for (i = 0; attr_names[i].str; ++i) {
             if (!av_strcasecmp(attr, attr_names[i].str)) {
                 if (attr_names[i].type == ATTR_NAME_TYPE_INT) {
                     *(int *)((char *)data+
                         attr_names[i].offset) = atoi(value);
                 } else if (attr_names[i].type == ATTR_NAME_TYPE_STR)
                     *(char **)((char *)data+
                         attr_names[i].offset) = av_strdup(value);
             }
         }
     }
     return 0;
 }

 static int parse_sdp_line(AVFormatContext *s, int st_index,
                           PayloadContext *data, const char *line)
 {
     const char *p;

     if (st_index < 0)
         return 0;

     if (av_strstart(line, "fmtp:", &p))
         return ff_parse_fmtp(s->streams[st_index], data, p, parse_fmtp);

     return 0;
 }

 static int init_video(AVFormatContext *s, int st_index, PayloadContext *data)
 {
     if (st_index < 0)
         return 0;
     s->streams[st_index]->need_parsing = AVSTREAM_PARSE_FULL;
     return 0;
 }

 RTPDynamicProtocolHandler ff_mp4v_es_dynamic_handler = {
     .enc_name           = "MP4V-ES",
     .codec_type         = AVMEDIA_TYPE_VIDEO,
     .codec_id           = AV_CODEC_ID_MPEG4,
     .init               = init_video,
     .parse_sdp_a_line   = parse_sdp_line,
 };

 RTPDynamicProtocolHandler ff_mpeg4_generic_dynamic_handler = {
     .enc_name           = "mpeg4-generic",
     .codec_type         = AVMEDIA_TYPE_AUDIO,
     .codec_id           = AV_CODEC_ID_AAC,
     .parse_sdp_a_line   = parse_sdp_line,
     .alloc              = new_context,
     .free               = free_context,
     .parse_packet       = aac_parse_packet
 };
	/*
	* Common code for the RTP depacketization of MPEG-4 formats.
	* Copyright (c) 2010 Fabrice Bellard
	* Romain Degez
	*
	* 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
	*/

	/**
	* @file
	* @brief MPEG4 / RTP Code
	* @author Fabrice Bellard
	* @author Romain Degez
	*/

	#include "rtpdec_formats.h"
	#include "internal.h"
	#include "libavutil/avstring.h"
	#include "libavcodec/get_bits.h"

	/** Structure listing useful vars to parse RTP packet payload */
	struct PayloadContext {
	int sizelength;
	int indexlength;
	int indexdeltalength;
	int profile_level_id;
	int streamtype;
	int objecttype;
	char *mode;

	/** mpeg 4 AU headers */
	struct AUHeaders {
	int size;
	int index;
	int cts_flag;
	int cts;
	int dts_flag;
	int dts;
	int rap_flag;
	int streamstate;
	} *au_headers;
	int au_headers_allocated;
	int nb_au_headers;
	int au_headers_length_bytes;
	int cur_au_index;

	uint8_t buf[RTP_MAX_PACKET_LENGTH];
	int buf_pos, buf_size;
	};

	typedef struct {
	const char *str;
	uint16_t type;
	uint32_t offset;
	} AttrNameMap;

	/* All known fmtp parameters and the corresponding RTPAttrTypeEnum */
	#define ATTR_NAME_TYPE_INT 0
	#define ATTR_NAME_TYPE_STR 1
	static const AttrNameMap attr_names[] = {
	{ "SizeLength", ATTR_NAME_TYPE_INT,
	offsetof(PayloadContext, sizelength) },
	{ "IndexLength", ATTR_NAME_TYPE_INT,
	offsetof(PayloadContext, indexlength) },
	{ "IndexDeltaLength", ATTR_NAME_TYPE_INT,
	offsetof(PayloadContext, indexdeltalength) },
	{ "profile-level-id", ATTR_NAME_TYPE_INT,
	offsetof(PayloadContext, profile_level_id) },
	{ "StreamType", ATTR_NAME_TYPE_INT,
	offsetof(PayloadContext, streamtype) },
	{ "mode", ATTR_NAME_TYPE_STR,
	offsetof(PayloadContext, mode) },
	{ NULL, -1, -1 },
	};

	static PayloadContext *new_context(void)
	{
	return av_mallocz(sizeof(PayloadContext));
	}

	static void free_context(PayloadContext *data)
	{
	av_free(data->au_headers);
	av_free(data->mode);
	av_free(data);
	}

	static int parse_fmtp_config(AVCodecContext codec, char value)
	{
	/* decode the hexa encoded parameter */
	int len = ff_hex_to_data(NULL, value);
	av_free(codec->extradata);
	codec->extradata = av_mallocz(len + FF_INPUT_BUFFER_PADDING_SIZE);
	if (!codec->extradata)
	return AVERROR(ENOMEM);
	codec->extradata_size = len;
	ff_hex_to_data(codec->extradata, value);
	return 0;
	}

	static int rtp_parse_mp4_au(PayloadContext data, const uint8_t buf, int len)
	{
	int au_headers_length, au_header_size, i;
	GetBitContext getbitcontext;

	if (len < 2)
	return AVERROR_INVALIDDATA;

	/* decode the first 2 bytes where the AUHeader sections are stored
	length in bits */
	au_headers_length = AV_RB16(buf);

	if (au_headers_length > RTP_MAX_PACKET_LENGTH)
	return -1;

	data->au_headers_length_bytes = (au_headers_length + 7) / 8;

	/* skip AU headers length section (2 bytes) */
	buf += 2;
	len -= 2;

	if (len < data->au_headers_length_bytes)
	return AVERROR_INVALIDDATA;

	init_get_bits(&getbitcontext, buf, data->au_headers_length_bytes * 8);

	/* XXX: Wrong if optional additional sections are present (cts, dts etc...) */
	au_header_size = data->sizelength + data->indexlength;
	if (au_header_size <= 0 \|\| (au_headers_length % au_header_size != 0))
	return -1;

	data->nb_au_headers = au_headers_length / au_header_size;
	if (!data->au_headers \|\| data->au_headers_allocated < data->nb_au_headers) {
	av_free(data->au_headers);
	data->au_headers = av_malloc(sizeof(struct AUHeaders) * data->nb_au_headers);
	if (!data->au_headers)
	return AVERROR(ENOMEM);
	data->au_headers_allocated = data->nb_au_headers;
	}

	for (i = 0; i < data->nb_au_headers; ++i) {
	data->au_headers[i].size = get_bits_long(&getbitcontext, data->sizelength);
	data->au_headers[i].index = get_bits_long(&getbitcontext, data->indexlength);
	}

	return 0;
	}


	/* Follows RFC 3640 */
	static int aac_parse_packet(AVFormatContext ctx, PayloadContext data,
	AVStream st, AVPacket pkt, uint32_t *timestamp,
	const uint8_t *buf, int len, uint16_t seq,
	int flags)
	{
	int ret;

	if (!buf) {
	if (data->cur_au_index > data->nb_au_headers)
	return AVERROR_INVALIDDATA;
	if (data->buf_size - data->buf_pos < data->au_headers[data->cur_au_index].size)
	return AVERROR_INVALIDDATA;
	if ((ret = av_new_packet(pkt, data->au_headers[data->cur_au_index].size)) < 0)
	return ret;
	memcpy(pkt->data, &data->buf[data->buf_pos], data->au_headers[data->cur_au_index].size);
	data->buf_pos += data->au_headers[data->cur_au_index].size;
	pkt->stream_index = st->index;
	data->cur_au_index++;
	return data->cur_au_index < data->nb_au_headers;
	}

	if (rtp_parse_mp4_au(data, buf, len))
	return -1;

	buf += data->au_headers_length_bytes + 2;
	len -= data->au_headers_length_bytes + 2;

	if (len < data->au_headers[0].size)
	return AVERROR_INVALIDDATA;
	if ((ret = av_new_packet(pkt, data->au_headers[0].size)) < 0)
	return ret;
	memcpy(pkt->data, buf, data->au_headers[0].size);
	len -= data->au_headers[0].size;
	buf += data->au_headers[0].size;
	pkt->stream_index = st->index;

	if (len > 0 && data->nb_au_headers > 1) {
	data->buf_size = FFMIN(len, sizeof(data->buf));
	memcpy(data->buf, buf, data->buf_size);
	data->cur_au_index = 1;
	data->buf_pos = 0;
	return 1;
	}

	return 0;
	}

	static int parse_fmtp(AVStream stream, PayloadContext data,
	char attr, char value)
	{
	AVCodecContext *codec = stream->codec;
	int res, i;

	if (!strcmp(attr, "config")) {
	res = parse_fmtp_config(codec, value);

	if (res < 0)
	return res;
	}

	if (codec->codec_id == AV_CODEC_ID_AAC) {
	/* Looking for a known attribute */
	for (i = 0; attr_names[i].str; ++i) {
	if (!av_strcasecmp(attr, attr_names[i].str)) {
	if (attr_names[i].type == ATTR_NAME_TYPE_INT) {
	(int )((char *)data+
	attr_names[i].offset) = atoi(value);
	} else if (attr_names[i].type == ATTR_NAME_TYPE_STR)
	(char )((char )data+
	attr_names[i].offset) = av_strdup(value);
	}
	}
	}
	return 0;
	}

	static int parse_sdp_line(AVFormatContext *s, int st_index,
	PayloadContext data, const char line)
	{
	const char *p;

	if (st_index < 0)
	return 0;

	if (av_strstart(line, "fmtp:", &p))
	return ff_parse_fmtp(s->streams[st_index], data, p, parse_fmtp);

	return 0;
	}

	static int init_video(AVFormatContext s, int st_index, PayloadContext data)
	{
	if (st_index < 0)
	return 0;
	s->streams[st_index]->need_parsing = AVSTREAM_PARSE_FULL;
	return 0;
	}

	RTPDynamicProtocolHandler ff_mp4v_es_dynamic_handler = {
	.enc_name = "MP4V-ES",
	.codec_type = AVMEDIA_TYPE_VIDEO,
	.codec_id = AV_CODEC_ID_MPEG4,
	.init = init_video,
	.parse_sdp_a_line = parse_sdp_line,
	};

	RTPDynamicProtocolHandler ff_mpeg4_generic_dynamic_handler = {
	.enc_name = "mpeg4-generic",
	.codec_type = AVMEDIA_TYPE_AUDIO,
	.codec_id = AV_CODEC_ID_AAC,
	.parse_sdp_a_line = parse_sdp_line,
	.alloc = new_context,
	.free = free_context,
	.parse_packet = aac_parse_packet
	};