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ffmpeg / libavformat / rtpdec_vorbis.c @ f65919af

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/*
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 * RTP Vorbis Protocol (RFC5215)
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 * Copyright (c) 2009 Colin McQuillan
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 *
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 * This file is part of FFmpeg.
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 *
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 * FFmpeg is free software; you can redistribute it and/or
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 * modify it under the terms of the GNU Lesser General Public
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 * License as published by the Free Software Foundation; either
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 * version 2.1 of the License, or (at your option) any later version.
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 *
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 * FFmpeg is distributed in the hope that it will be useful,
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 * but WITHOUT ANY WARRANTY; without even the implied warranty of
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 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
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 * Lesser General Public License for more details.
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 *
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 * You should have received a copy of the GNU Lesser General Public
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 * License along with FFmpeg; if not, write to the Free Software
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 * Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA
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 */
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/**
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 * @file libavformat/rtpdec_vorbis.c
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 * @brief Vorbis / RTP Code (RFC 5215)
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 * @author Colin McQuillan <m.niloc@gmail.com>
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 */
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#include "libavutil/base64.h"
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#include "libavutil/avstring.h"
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#include "libavcodec/bytestream.h"
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#include <assert.h>
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#include "rtpdec.h"
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#include "rtpdec_vorbis.h"
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/**
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 * RTP/Vorbis specific private data.
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 */
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struct PayloadContext {
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    unsigned ident;             ///< 24-bit stream configuration identifier
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};
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/**
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 * Length encoding described in RFC5215 section 3.1.1.
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 */
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static int get_base128(const uint8_t ** buf, const uint8_t * buf_end)
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{
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    int n = 0;
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    for (; *buf < buf_end; ++*buf) {
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        n <<= 7;
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        n += **buf & 0x7f;
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        if (!(**buf & 0x80)) {
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            ++*buf;
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            return n;
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        }
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    }
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    return 0;
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}
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/**
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 * Out-of-band headers, described in RFC 5251 section 3.2.1
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 */
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static unsigned int
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parse_packed_headers(const uint8_t * packed_headers,
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                     const uint8_t * packed_headers_end,
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                     AVCodecContext * codec, PayloadContext * vorbis_data)
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{
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    unsigned num_packed, num_headers, length, length1, length2;
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    uint8_t *ptr;
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    num_packed         = bytestream_get_be32(&packed_headers);
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    vorbis_data->ident = bytestream_get_be24(&packed_headers);
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    length             = bytestream_get_be16(&packed_headers);
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    num_headers        = get_base128(&packed_headers, packed_headers_end);
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    length1            = get_base128(&packed_headers, packed_headers_end);
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    length2            = get_base128(&packed_headers, packed_headers_end);
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    if (num_packed != 1 || num_headers > 3) {
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        av_log(codec, AV_LOG_ERROR,
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               "Unimplemented number of headers: %d packed headers, %d headers\n",
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               num_packed, num_headers);
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        return AVERROR_PATCHWELCOME;
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    }
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    if (packed_headers_end - packed_headers != length ||
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        length1 > length || length2 > length - length1) {
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        av_log(codec, AV_LOG_ERROR,
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               "Bad packed header lengths (%d,%d,%d,%d)\n", length1,
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               length2, packed_headers_end - packed_headers, length);
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        return AVERROR_INVALIDDATA;
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    }
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    ptr = codec->extradata = av_mallocz(length + length / 255 + 64);
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    if (!ptr) {
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        av_log(codec, AV_LOG_ERROR, "Out of memory");
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        return AVERROR_NOMEM;
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    }
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    *ptr++ = 2;
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    ptr += av_xiphlacing(ptr, length1);
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    ptr += av_xiphlacing(ptr, length2);
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    memcpy(ptr, packed_headers, length);
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    ptr += length;
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    codec->extradata_size = ptr - codec->extradata;
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    return 0;
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}
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int
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ff_vorbis_parse_fmtp_config(AVCodecContext * codec,
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                            void *vorbis_data, char *attr, char *value)
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{
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    int result = 0;
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    assert(codec->codec_id == CODEC_ID_VORBIS);
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    assert(vorbis_data);
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    // The configuration value is a base64 encoded packed header
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    if (!strcmp(attr, "configuration")) {
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        uint8_t *decoded_packet = NULL;
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        int packet_size;
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        size_t decoded_alloc = strlen(value) / 4 * 3 + 4;
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        if (decoded_alloc <= INT_MAX) {
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            decoded_packet = av_malloc(decoded_alloc);
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            if (decoded_packet) {
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                packet_size =
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                    av_base64_decode(decoded_packet, value, decoded_alloc);
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                result = parse_packed_headers
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                    (decoded_packet, decoded_packet + packet_size, codec,
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                     vorbis_data);
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            } else {
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                av_log(codec, AV_LOG_ERROR,
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                       "Out of memory while decoding SDP configuration.\n");
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                result = AVERROR_NOMEM;
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            }
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        } else {
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            av_log(codec, AV_LOG_ERROR, "Packet too large\n");
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            result = AVERROR_INVALIDDATA;
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        }
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        av_free(decoded_packet);
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    }
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    return result;
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}
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static PayloadContext *vorbis_new_context(void)
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{
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    return av_mallocz(sizeof(PayloadContext));
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}
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static void vorbis_free_context(PayloadContext * data)
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{
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    av_free(data);
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}
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/**
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 * Handle payload as described in RFC 5215 section 2.2
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 */
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static int
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vorbis_handle_packet(AVFormatContext * ctx,
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                     PayloadContext * data,
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                     AVStream * st,
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                     AVPacket * pkt,
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                     uint32_t * timestamp,
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                     const uint8_t * buf, int len, int flags)
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{
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    int ident, fragmented, vdt, num_pkts, pkt_len;
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    if (len < 6) {
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        av_log(ctx, AV_LOG_ERROR, "Invalid %d byte packet\n", len);
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        return AVERROR_INVALIDDATA;
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    }
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    ident = AV_RB24(buf);
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    fragmented = buf[3] >> 6;
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    vdt = (buf[3] >> 4) & 3;
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    num_pkts = buf[3] & 7;
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    pkt_len = AV_RB16(buf + 4);
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    if (pkt_len > len - 6) {
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        av_log(ctx, AV_LOG_ERROR,
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               "Invalid packet length %d in %d byte packet\n", pkt_len,
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               len);
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        return AVERROR_INVALIDDATA;
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    }
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    if (ident != data->ident) {
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        av_log(ctx, AV_LOG_ERROR,
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               "Unimplemented Vorbis SDP configuration change detected\n");
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        return AVERROR_PATCHWELCOME;
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    }
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    if (fragmented != 0 || vdt != 0 || num_pkts != 1) {
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        av_log(ctx, AV_LOG_ERROR,
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               "Unimplemented RTP Vorbis packet settings (%d,%d,%d)\n",
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               fragmented, vdt, num_pkts);
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        return AVERROR_PATCHWELCOME;
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    }
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    if (av_new_packet(pkt, pkt_len)) {
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        av_log(ctx, AV_LOG_ERROR, "Out of memory.\n");
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        return AVERROR_NOMEM;
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    }
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    memcpy(pkt->data, buf + 6, pkt_len);
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    pkt->stream_index = st->index;
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    return 0;
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}
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RTPDynamicProtocolHandler ff_vorbis_dynamic_handler = {
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    .enc_name         = "vorbis",
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    .codec_type       = CODEC_TYPE_AUDIO,
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    .codec_id         = CODEC_ID_VORBIS,
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    .parse_sdp_a_line = NULL,
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    .open             = vorbis_new_context,
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    .close            = vorbis_free_context,
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    .parse_packet     = vorbis_handle_packet
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};