/* * Musepack demuxer * Copyright (c) 2006 Konstantin Shishkov * * 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 "libavcodec/bitstream.h" #include "avformat.h" #include "id3v2.h" #define MPC_FRAMESIZE 1152 #define DELAY_FRAMES 32 static const int mpc_rate[4] = { 44100, 48000, 37800, 32000 }; typedef struct { int64_t pos; int size, skip; }MPCFrame; typedef struct { int ver; uint32_t curframe, lastframe; uint32_t fcount; MPCFrame *frames; int curbits; int frames_noted; } MPCContext; static int mpc_probe(AVProbeData *p) { const uint8_t *d = p->buf; if (ff_id3v2_match(d)) { d += ff_id3v2_tag_len(d); } if (d+3 < p->buf+p->buf_size) if (d[0] == 'M' && d[1] == 'P' && d[2] == '+' && (d[3] == 0x17 || d[3] == 0x7)) return AVPROBE_SCORE_MAX; return 0; } static int mpc_read_header(AVFormatContext *s, AVFormatParameters *ap) { MPCContext *c = s->priv_data; AVStream *st; int t; t = get_le24(s->pb); if(t != MKTAG('M', 'P', '+', 0)){ if(t != MKTAG('I', 'D', '3', 0)){ av_log(s, AV_LOG_ERROR, "Not a Musepack file\n"); return -1; } /* skip ID3 tags and try again */ url_fskip(s->pb, 3); t = get_byte(s->pb) << 21; t |= get_byte(s->pb) << 14; t |= get_byte(s->pb) << 7; t |= get_byte(s->pb); av_log(s, AV_LOG_DEBUG, "Skipping %d(%X) bytes of ID3 data\n", t, t); url_fskip(s->pb, t); if(get_le24(s->pb) != MKTAG('M', 'P', '+', 0)){ av_log(s, AV_LOG_ERROR, "Not a Musepack file\n"); return -1; } } c->ver = get_byte(s->pb); if(c->ver != 0x07 && c->ver != 0x17){ av_log(s, AV_LOG_ERROR, "Can demux Musepack SV7, got version %02X\n", c->ver); return -1; } c->fcount = get_le32(s->pb); if((int64_t)c->fcount * sizeof(MPCFrame) >= UINT_MAX){ av_log(s, AV_LOG_ERROR, "Too many frames, seeking is not possible\n"); return -1; } c->frames = av_malloc(c->fcount * sizeof(MPCFrame)); c->curframe = 0; c->lastframe = -1; c->curbits = 8; c->frames_noted = 0; st = av_new_stream(s, 0); if (!st) return AVERROR(ENOMEM); st->codec->codec_type = CODEC_TYPE_AUDIO; st->codec->codec_id = CODEC_ID_MUSEPACK7; st->codec->channels = 2; st->codec->bits_per_coded_sample = 16; st->codec->extradata_size = 16; st->codec->extradata = av_mallocz(st->codec->extradata_size+FF_INPUT_BUFFER_PADDING_SIZE); get_buffer(s->pb, st->codec->extradata, 16); st->codec->sample_rate = mpc_rate[st->codec->extradata[2] & 3]; av_set_pts_info(st, 32, MPC_FRAMESIZE, st->codec->sample_rate); /* scan for seekpoints */ s->start_time = 0; s->duration = (int64_t)c->fcount * MPC_FRAMESIZE * AV_TIME_BASE / st->codec->sample_rate; return 0; } static int mpc_read_packet(AVFormatContext *s, AVPacket *pkt) { MPCContext *c = s->priv_data; int ret, size, size2, curbits, cur = c->curframe; int64_t tmp, pos; if (c->curframe >= c->fcount) return -1; if(c->curframe != c->lastframe + 1){ url_fseek(s->pb, c->frames[c->curframe].pos, SEEK_SET); c->curbits = c->frames[c->curframe].skip; } c->lastframe = c->curframe; c->curframe++; curbits = c->curbits; pos = url_ftell(s->pb); tmp = get_le32(s->pb); if(curbits <= 12){ size2 = (tmp >> (12 - curbits)) & 0xFFFFF; }else{ tmp = (tmp << 32) | get_le32(s->pb); size2 = (tmp >> (44 - curbits)) & 0xFFFFF; } curbits += 20; url_fseek(s->pb, pos, SEEK_SET); size = ((size2 + curbits + 31) & ~31) >> 3; if(cur == c->frames_noted){ c->frames[cur].pos = pos; c->frames[cur].size = size; c->frames[cur].skip = curbits - 20; av_add_index_entry(s->streams[0], cur, cur, size, 0, AVINDEX_KEYFRAME); c->frames_noted++; } c->curbits = (curbits + size2) & 0x1F; if (av_new_packet(pkt, size) < 0) return AVERROR(EIO); pkt->data[0] = curbits; pkt->data[1] = (c->curframe > c->fcount); pkt->stream_index = 0; pkt->pts = cur; ret = get_buffer(s->pb, pkt->data + 4, size); if(c->curbits) url_fseek(s->pb, -4, SEEK_CUR); if(ret < size){ av_free_packet(pkt); return AVERROR(EIO); } pkt->size = ret + 4; return 0; } static int mpc_read_close(AVFormatContext *s) { MPCContext *c = s->priv_data; av_freep(&c->frames); return 0; } /** * Seek to the given position * If position is unknown but is within the limits of file * then packets are skipped unless desired position is reached * * Also this function makes use of the fact that timestamp == frameno */ static int mpc_read_seek(AVFormatContext *s, int stream_index, int64_t timestamp, int flags) { AVStream *st = s->streams[stream_index]; MPCContext *c = s->priv_data; AVPacket pkt1, *pkt = &pkt1; int ret; int index = av_index_search_timestamp(st, timestamp - DELAY_FRAMES, flags); uint32_t lastframe; /* if found, seek there */ if (index >= 0){ c->curframe = st->index_entries[index].pos; return 0; } /* if timestamp is out of bounds, return error */ if(timestamp < 0 || timestamp >= c->fcount) return -1; timestamp -= DELAY_FRAMES; /* seek to the furthest known position and read packets until we reach desired position */ lastframe = c->curframe; if(c->frames_noted) c->curframe = c->frames_noted - 1; while(c->curframe < timestamp){ ret = av_read_frame(s, pkt); if (ret < 0){ c->curframe = lastframe; return -1; } av_free_packet(pkt); } return 0; } AVInputFormat mpc_demuxer = { "mpc", NULL_IF_CONFIG_SMALL("Musepack"), sizeof(MPCContext), mpc_probe, mpc_read_header, mpc_read_packet, mpc_read_close, mpc_read_seek, .extensions = "mpc", };