/* * raw ADTS AAC demuxer * Copyright (c) 2008 Michael Niedermayer <michaelni@gmx.at> * Copyright (c) 2009 Robert Swain ( rob opendot cl ) * * 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/avassert.h"#include "libavutil/intreadwrite.h"#include "avformat.h"#include "avio_internal.h"#include "demux.h"#include "internal.h"#include "id3v1.h"#include "id3v2.h"#include "apetag.h" #define ADTS_HEADER_SIZE 7 static int adts_aac_probe(const AVProbeData *p){    int max_frames = 0, first_frames = 0;    int fsize, frames;    const uint8_t *buf0 = p->buf;    const uint8_t *buf2;    const uint8_t *buf;    const uint8_t *end = buf0 + p->buf_size - 7;     buf = buf0;     for (; buf < end; buf = buf2 + 1) {        buf2 = buf;         for (frames = 0; buf2 < end; frames++) {            uint32_t header = AV_RB16(buf2);            if ((header & 0xFFF6) != 0xFFF0) {                if (buf != buf0) {                    // Found something that isn't an ADTS header, starting                    // from a position other than the start of the buffer.                    // Discard the count we've accumulated so far since it                    // probably was a false positive.                    frames = 0;                }                break;            }            fsize = (AV_RB32(buf2 + 3) >> 13) & 0x1FFF;            if (fsize < 7)                break;            fsize = FFMIN(fsize, end - buf2);            buf2 += fsize;        }        max_frames = FFMAX(max_frames, frames);        if (buf == buf0)            first_frames = frames;    }     if (first_frames >= 3)        return AVPROBE_SCORE_EXTENSION + 1;    else if (max_frames > 100)        return AVPROBE_SCORE_EXTENSION;    else if (max_frames >= 3)        return AVPROBE_SCORE_EXTENSION / 2;    else if (first_frames >= 1)        return 1;    else        return 0;} static int adts_aac_resync(AVFormatContext *s){    uint16_t state;    int64_t start_pos = avio_tell(s->pb);     // skip data until an ADTS frame is found    state = avio_r8(s->pb);    while (!avio_feof(s->pb) &&           (avio_tell(s->pb) - start_pos) < s->probesize) {        state = (state << 8) | avio_r8(s->pb);        if ((state >> 4) != 0xFFF)            continue;        avio_seek(s->pb, -2, SEEK_CUR);        break;    }    if (s->pb->eof_reached)        return AVERROR_EOF;    if ((state >> 4) != 0xFFF)        return AVERROR_INVALIDDATA;     return 0;} static int adts_aac_read_header(AVFormatContext *s){    AVStream *st;    int ret;     st = avformat_new_stream(s, NULL);    if (!st)        return AVERROR(ENOMEM);     st->codecpar->codec_type = AVMEDIA_TYPE_AUDIO;    st->codecpar->codec_id   = AV_CODEC_ID_AAC;    ffstream(st)->need_parsing = AVSTREAM_PARSE_FULL_RAW;     ff_id3v1_read(s);    if ((s->pb->seekable & AVIO_SEEKABLE_NORMAL) &&        !av_dict_count(s->metadata)) {        int64_t cur = avio_tell(s->pb);        ff_ape_parse_tag(s);        avio_seek(s->pb, cur, SEEK_SET);    }     ret = adts_aac_resync(s);    if (ret < 0)        return ret;     // LCM of all possible ADTS sample rates    avpriv_set_pts_info(st, 64, 1, 28224000);     return 0;} static int handle_id3(AVFormatContext *s, AVPacket *pkt){    AVDictionary *metadata = NULL;    FFIOContext pb;    ID3v2ExtraMeta *id3v2_extra_meta;    int ret;     ret = av_append_packet(s->pb, pkt, ff_id3v2_tag_len(pkt->data) - pkt->size);    if (ret < 0)        return ret;     ffio_init_read_context(&pb, pkt->data, pkt->size);    ff_id3v2_read_dict(&pb.pub, &metadata, ID3v2_DEFAULT_MAGIC, &id3v2_extra_meta);    if ((ret = ff_id3v2_parse_priv_dict(&metadata, id3v2_extra_meta)) < 0)        goto error;     if (metadata) {        if ((ret = av_dict_copy(&s->metadata, metadata, 0)) < 0)            goto error;        s->event_flags |= AVFMT_EVENT_FLAG_METADATA_UPDATED;    } error:    av_packet_unref(pkt);    ff_id3v2_free_extra_meta(&id3v2_extra_meta);    av_dict_free(&metadata);     return ret;} static int adts_aac_read_packet(AVFormatContext *s, AVPacket *pkt){    int ret, fsize; retry:    ret = av_get_packet(s->pb, pkt, ADTS_HEADER_SIZE);    if (ret < 0)        return ret;     if (ret < ADTS_HEADER_SIZE)        return AVERROR(EIO);     if ((AV_RB16(pkt->data) >> 4) != 0xfff) {        // Parse all the ID3 headers between frames        int append = ID3v2_HEADER_SIZE - ADTS_HEADER_SIZE;         av_assert2(append > 0);        ret = av_append_packet(s->pb, pkt, append);        if (ret != append)            return AVERROR(EIO);        if (!ff_id3v2_match(pkt->data, ID3v2_DEFAULT_MAGIC)) {            av_packet_unref(pkt);            ret = adts_aac_resync(s);        } else            ret = handle_id3(s, pkt);        if (ret < 0)            return ret;         goto retry;    }     fsize = (AV_RB32(pkt->data + 3) >> 13) & 0x1FFF;    if (fsize < ADTS_HEADER_SIZE)        return AVERROR_INVALIDDATA;     ret = av_append_packet(s->pb, pkt, fsize - pkt->size);     return ret;} const FFInputFormat ff_aac_demuxer = {    .p.name       = "aac",    .p.long_name  = NULL_IF_CONFIG_SMALL("raw ADTS AAC (Advanced Audio Coding)"),    .p.flags      = AVFMT_GENERIC_INDEX,    .p.extensions = "aac",    .p.mime_type  = "audio/aac,audio/aacp,audio/x-aac",    .read_probe   = adts_aac_probe,    .read_header  = adts_aac_read_header,    .read_packet  = adts_aac_read_packet,    .raw_codec_id = AV_CODEC_ID_AAC,};