yading@11: /*
yading@11:  * RTP Depacketization of MP4A-LATM, RFC 3016
yading@11:  * Copyright (c) 2010 Martin Storsjo
yading@11:  *
yading@11:  * This file is part of FFmpeg.
yading@11:  *
yading@11:  * FFmpeg is free software; you can redistribute it and/or
yading@11:  * modify it under the terms of the GNU Lesser General Public
yading@11:  * License as published by the Free Software Foundation; either
yading@11:  * version 2.1 of the License, or (at your option) any later version.
yading@11:  *
yading@11:  * FFmpeg is distributed in the hope that it will be useful,
yading@11:  * but WITHOUT ANY WARRANTY; without even the implied warranty of
yading@11:  * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
yading@11:  * Lesser General Public License for more details.
yading@11:  *
yading@11:  * You should have received a copy of the GNU Lesser General Public
yading@11:  * License along with FFmpeg; if not, write to the Free Software
yading@11:  * Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA
yading@11:  */
yading@11: 
yading@11: #include "rtpdec_formats.h"
yading@11: #include "internal.h"
yading@11: #include "libavutil/avstring.h"
yading@11: #include "libavcodec/get_bits.h"
yading@11: 
yading@11: struct PayloadContext {
yading@11:     AVIOContext *dyn_buf;
yading@11:     uint8_t *buf;
yading@11:     int pos, len;
yading@11:     uint32_t timestamp;
yading@11: };
yading@11: 
yading@11: static PayloadContext *latm_new_context(void)
yading@11: {
yading@11:     return av_mallocz(sizeof(PayloadContext));
yading@11: }
yading@11: 
yading@11: static void latm_free_context(PayloadContext *data)
yading@11: {
yading@11:     if (!data)
yading@11:         return;
yading@11:     if (data->dyn_buf) {
yading@11:         uint8_t *p;
yading@11:         avio_close_dyn_buf(data->dyn_buf, &p);
yading@11:         av_free(p);
yading@11:     }
yading@11:     av_free(data->buf);
yading@11:     av_free(data);
yading@11: }
yading@11: 
yading@11: static int latm_parse_packet(AVFormatContext *ctx, PayloadContext *data,
yading@11:                              AVStream *st, AVPacket *pkt, uint32_t *timestamp,
yading@11:                              const uint8_t *buf, int len, uint16_t seq,
yading@11:                              int flags)
yading@11: {
yading@11:     int ret, cur_len;
yading@11: 
yading@11:     if (buf) {
yading@11:         if (!data->dyn_buf || data->timestamp != *timestamp) {
yading@11:             av_freep(&data->buf);
yading@11:             if (data->dyn_buf)
yading@11:                 avio_close_dyn_buf(data->dyn_buf, &data->buf);
yading@11:             data->dyn_buf = NULL;
yading@11:             av_freep(&data->buf);
yading@11: 
yading@11:             data->timestamp = *timestamp;
yading@11:             if ((ret = avio_open_dyn_buf(&data->dyn_buf)) < 0)
yading@11:                 return ret;
yading@11:         }
yading@11:         avio_write(data->dyn_buf, buf, len);
yading@11: 
yading@11:         if (!(flags & RTP_FLAG_MARKER))
yading@11:             return AVERROR(EAGAIN);
yading@11:         av_free(data->buf);
yading@11:         data->len = avio_close_dyn_buf(data->dyn_buf, &data->buf);
yading@11:         data->dyn_buf = NULL;
yading@11:         data->pos = 0;
yading@11:     }
yading@11: 
yading@11:     if (!data->buf) {
yading@11:         av_log(ctx, AV_LOG_ERROR, "No data available yet\n");
yading@11:         return AVERROR(EIO);
yading@11:     }
yading@11: 
yading@11:     cur_len = 0;
yading@11:     while (data->pos < data->len) {
yading@11:         uint8_t val = data->buf[data->pos++];
yading@11:         cur_len += val;
yading@11:         if (val != 0xff)
yading@11:             break;
yading@11:     }
yading@11:     if (data->pos + cur_len > data->len) {
yading@11:         av_log(ctx, AV_LOG_ERROR, "Malformed LATM packet\n");
yading@11:         return AVERROR(EIO);
yading@11:     }
yading@11: 
yading@11:     if ((ret = av_new_packet(pkt, cur_len)) < 0)
yading@11:         return ret;
yading@11:     memcpy(pkt->data, data->buf + data->pos, cur_len);
yading@11:     data->pos += cur_len;
yading@11:     pkt->stream_index = st->index;
yading@11:     return data->pos < data->len;
yading@11: }
yading@11: 
yading@11: static int parse_fmtp_config(AVStream *st, char *value)
yading@11: {
yading@11:     int len = ff_hex_to_data(NULL, value), i, ret = 0;
yading@11:     GetBitContext gb;
yading@11:     uint8_t *config;
yading@11:     int audio_mux_version, same_time_framing, num_programs, num_layers;
yading@11: 
yading@11:     /* Pad this buffer, too, to avoid out of bounds reads with get_bits below */
yading@11:     config = av_mallocz(len + FF_INPUT_BUFFER_PADDING_SIZE);
yading@11:     if (!config)
yading@11:         return AVERROR(ENOMEM);
yading@11:     ff_hex_to_data(config, value);
yading@11:     init_get_bits(&gb, config, len*8);
yading@11:     audio_mux_version = get_bits(&gb, 1);
yading@11:     same_time_framing = get_bits(&gb, 1);
yading@11:     skip_bits(&gb, 6); /* num_sub_frames */
yading@11:     num_programs      = get_bits(&gb, 4);
yading@11:     num_layers        = get_bits(&gb, 3);
yading@11:     if (audio_mux_version != 0 || same_time_framing != 1 || num_programs != 0 ||
yading@11:         num_layers != 0) {
yading@11:         av_log(NULL, AV_LOG_WARNING, "Unsupported LATM config (%d,%d,%d,%d)\n",
yading@11:                                      audio_mux_version, same_time_framing,
yading@11:                                      num_programs, num_layers);
yading@11:         ret = AVERROR_PATCHWELCOME;
yading@11:         goto end;
yading@11:     }
yading@11:     av_freep(&st->codec->extradata);
yading@11:     st->codec->extradata_size = (get_bits_left(&gb) + 7)/8;
yading@11:     st->codec->extradata = av_mallocz(st->codec->extradata_size +
yading@11:                                       FF_INPUT_BUFFER_PADDING_SIZE);
yading@11:     if (!st->codec->extradata) {
yading@11:         ret = AVERROR(ENOMEM);
yading@11:         goto end;
yading@11:     }
yading@11:     for (i = 0; i < st->codec->extradata_size; i++)
yading@11:         st->codec->extradata[i] = get_bits(&gb, 8);
yading@11: 
yading@11: end:
yading@11:     av_free(config);
yading@11:     return ret;
yading@11: }
yading@11: 
yading@11: static int parse_fmtp(AVStream *stream, PayloadContext *data,
yading@11:                       char *attr, char *value)
yading@11: {
yading@11:     int res;
yading@11: 
yading@11:     if (!strcmp(attr, "config")) {
yading@11:         res = parse_fmtp_config(stream, value);
yading@11:         if (res < 0)
yading@11:             return res;
yading@11:     } else if (!strcmp(attr, "cpresent")) {
yading@11:         int cpresent = atoi(value);
yading@11:         if (cpresent != 0)
yading@11:             avpriv_request_sample(NULL,
yading@11:                                   "RTP MP4A-LATM with in-band configuration");
yading@11:     }
yading@11: 
yading@11:     return 0;
yading@11: }
yading@11: 
yading@11: static int latm_parse_sdp_line(AVFormatContext *s, int st_index,
yading@11:                                PayloadContext *data, const char *line)
yading@11: {
yading@11:     const char *p;
yading@11: 
yading@11:     if (st_index < 0)
yading@11:         return 0;
yading@11: 
yading@11:     if (av_strstart(line, "fmtp:", &p))
yading@11:         return ff_parse_fmtp(s->streams[st_index], data, p, parse_fmtp);
yading@11: 
yading@11:     return 0;
yading@11: }
yading@11: 
yading@11: RTPDynamicProtocolHandler ff_mp4a_latm_dynamic_handler = {
yading@11:     .enc_name           = "MP4A-LATM",
yading@11:     .codec_type         = AVMEDIA_TYPE_AUDIO,
yading@11:     .codec_id           = AV_CODEC_ID_AAC,
yading@11:     .parse_sdp_a_line   = latm_parse_sdp_line,
yading@11:     .alloc              = latm_new_context,
yading@11:     .free               = latm_free_context,
yading@11:     .parse_packet       = latm_parse_packet
yading@11: };