3 * Copyright (c) 2006 Konstantin Shishkov
5 * This file is part of FFmpeg.
7 * FFmpeg is free software; you can redistribute it and/or
8 * modify it under the terms of the GNU Lesser General Public
9 * License as published by the Free Software Foundation; either
10 * version 2.1 of the License, or (at your option) any later version.
12 * FFmpeg is distributed in the hope that it will be useful,
13 * but WITHOUT ANY WARRANTY; without even the implied warranty of
14 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
15 * Lesser General Public License for more details.
17 * You should have received a copy of the GNU Lesser General Public
18 * License along with FFmpeg; if not, write to the Free Software
19 * Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA
22 #include "libavcodec/get_bits.h"
26 #define MPC_FRAMESIZE 1152
27 #define DELAY_FRAMES 32
29 static const int mpc_rate[4] = { 44100, 48000, 37800, 32000 };
37 uint32_t curframe, lastframe;
44 static int mpc_probe(AVProbeData *p)
46 const uint8_t *d = p->buf;
47 if (d[0] == 'M' && d[1] == 'P' && d[2] == '+' && (d[3] == 0x17 || d[3] == 0x7))
48 return AVPROBE_SCORE_MAX;
52 static int mpc_read_header(AVFormatContext *s, AVFormatParameters *ap)
54 MPCContext *c = s->priv_data;
57 if(get_le24(s->pb) != MKTAG('M', 'P', '+', 0)){
58 av_log(s, AV_LOG_ERROR, "Not a Musepack file\n");
61 c->ver = get_byte(s->pb);
62 if(c->ver != 0x07 && c->ver != 0x17){
63 av_log(s, AV_LOG_ERROR, "Can demux Musepack SV7, got version %02X\n", c->ver);
66 c->fcount = get_le32(s->pb);
67 if((int64_t)c->fcount * sizeof(MPCFrame) >= UINT_MAX){
68 av_log(s, AV_LOG_ERROR, "Too many frames, seeking is not possible\n");
71 c->frames = av_malloc(c->fcount * sizeof(MPCFrame));
77 st = av_new_stream(s, 0);
79 return AVERROR(ENOMEM);
80 st->codec->codec_type = AVMEDIA_TYPE_AUDIO;
81 st->codec->codec_id = CODEC_ID_MUSEPACK7;
82 st->codec->channels = 2;
83 st->codec->bits_per_coded_sample = 16;
85 st->codec->extradata_size = 16;
86 st->codec->extradata = av_mallocz(st->codec->extradata_size+FF_INPUT_BUFFER_PADDING_SIZE);
87 get_buffer(s->pb, st->codec->extradata, 16);
88 st->codec->sample_rate = mpc_rate[st->codec->extradata[2] & 3];
89 av_set_pts_info(st, 32, MPC_FRAMESIZE, st->codec->sample_rate);
90 /* scan for seekpoints */
92 st->duration = c->fcount;
94 /* try to read APE tags */
95 if (!url_is_streamed(s->pb)) {
96 int64_t pos = url_ftell(s->pb);
98 url_fseek(s->pb, pos, SEEK_SET);
104 static int mpc_read_packet(AVFormatContext *s, AVPacket *pkt)
106 MPCContext *c = s->priv_data;
107 int ret, size, size2, curbits, cur = c->curframe;
110 if (c->curframe >= c->fcount)
113 if(c->curframe != c->lastframe + 1){
114 url_fseek(s->pb, c->frames[c->curframe].pos, SEEK_SET);
115 c->curbits = c->frames[c->curframe].skip;
117 c->lastframe = c->curframe;
119 curbits = c->curbits;
120 pos = url_ftell(s->pb);
121 tmp = get_le32(s->pb);
123 size2 = (tmp >> (12 - curbits)) & 0xFFFFF;
125 tmp = (tmp << 32) | get_le32(s->pb);
126 size2 = (tmp >> (44 - curbits)) & 0xFFFFF;
129 url_fseek(s->pb, pos, SEEK_SET);
131 size = ((size2 + curbits + 31) & ~31) >> 3;
132 if(cur == c->frames_noted){
133 c->frames[cur].pos = pos;
134 c->frames[cur].size = size;
135 c->frames[cur].skip = curbits - 20;
136 av_add_index_entry(s->streams[0], cur, cur, size, 0, AVINDEX_KEYFRAME);
139 c->curbits = (curbits + size2) & 0x1F;
141 if (av_new_packet(pkt, size) < 0)
144 pkt->data[0] = curbits;
145 pkt->data[1] = (c->curframe > c->fcount);
149 pkt->stream_index = 0;
151 ret = get_buffer(s->pb, pkt->data + 4, size);
153 url_fseek(s->pb, -4, SEEK_CUR);
163 static int mpc_read_close(AVFormatContext *s)
165 MPCContext *c = s->priv_data;
167 av_freep(&c->frames);
172 * Seek to the given position
173 * If position is unknown but is within the limits of file
174 * then packets are skipped unless desired position is reached
176 * Also this function makes use of the fact that timestamp == frameno
178 static int mpc_read_seek(AVFormatContext *s, int stream_index, int64_t timestamp, int flags)
180 AVStream *st = s->streams[stream_index];
181 MPCContext *c = s->priv_data;
182 AVPacket pkt1, *pkt = &pkt1;
184 int index = av_index_search_timestamp(st, timestamp - DELAY_FRAMES, flags);
187 /* if found, seek there */
189 c->curframe = st->index_entries[index].pos;
192 /* if timestamp is out of bounds, return error */
193 if(timestamp < 0 || timestamp >= c->fcount)
195 timestamp -= DELAY_FRAMES;
196 /* seek to the furthest known position and read packets until
197 we reach desired position */
198 lastframe = c->curframe;
199 if(c->frames_noted) c->curframe = c->frames_noted - 1;
200 while(c->curframe < timestamp){
201 ret = av_read_frame(s, pkt);
203 c->curframe = lastframe;
212 AVInputFormat mpc_demuxer = {
214 NULL_IF_CONFIG_SMALL("Musepack"),