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 "bitstream.h"
24 #define MPC_FRAMESIZE 1152
25 #define DELAY_FRAMES 32
27 static const int mpc_rate[4] = { 44100, 48000, 37800, 32000 };
35 uint32_t curframe, lastframe;
42 static int mpc_probe(AVProbeData *p)
44 const uint8_t *d = p->buf;
45 if (d[0] == 'M' && d[1] == 'P' && d[2] == '+' && (d[3] == 0x17 || d[3] == 0x7))
46 return AVPROBE_SCORE_MAX;
47 if (d[0] == 'I' && d[1] == 'D' && d[2] == '3')
48 return AVPROBE_SCORE_MAX / 2;
52 static int mpc_read_header(AVFormatContext *s, AVFormatParameters *ap)
54 MPCContext *c = s->priv_data;
59 if(t != MKTAG('M', 'P', '+', 0)){
60 if(t != MKTAG('I', 'D', '3', 0)){
61 av_log(s, AV_LOG_ERROR, "Not a Musepack file\n");
64 /* skip ID3 tags and try again */
66 t = get_byte(&s->pb) << 21;
67 t |= get_byte(&s->pb) << 14;
68 t |= get_byte(&s->pb) << 7;
69 t |= get_byte(&s->pb);
70 av_log(s, AV_LOG_DEBUG, "Skipping %d(%X) bytes of ID3 data\n", t, t);
72 if(get_le24(&s->pb) != MKTAG('M', 'P', '+', 0)){
73 av_log(s, AV_LOG_ERROR, "Not a Musepack file\n");
77 c->ver = get_byte(&s->pb);
78 if(c->ver != 0x07 && c->ver != 0x17){
79 av_log(s, AV_LOG_ERROR, "Can demux Musepack SV7, got version %02X\n", c->ver);
82 c->fcount = get_le32(&s->pb);
83 if((int64_t)c->fcount * sizeof(MPCFrame) >= UINT_MAX){
84 av_log(s, AV_LOG_ERROR, "Too many frames, seeking is not possible\n");
87 c->frames = av_malloc(c->fcount * sizeof(MPCFrame));
93 st = av_new_stream(s, 0);
95 return AVERROR(ENOMEM);
96 st->codec->codec_type = CODEC_TYPE_AUDIO;
97 st->codec->codec_id = CODEC_ID_MUSEPACK7;
98 st->codec->channels = 2;
99 st->codec->bits_per_sample = 16;
101 st->codec->extradata_size = 16;
102 st->codec->extradata = av_mallocz(st->codec->extradata_size+FF_INPUT_BUFFER_PADDING_SIZE);
103 get_buffer(&s->pb, st->codec->extradata, 16);
104 st->codec->sample_rate = mpc_rate[st->codec->extradata[2] & 3];
105 av_set_pts_info(st, 32, MPC_FRAMESIZE, st->codec->sample_rate);
106 /* scan for seekpoints */
108 s->duration = (int64_t)c->fcount * MPC_FRAMESIZE * AV_TIME_BASE / st->codec->sample_rate;
113 static int mpc_read_packet(AVFormatContext *s, AVPacket *pkt)
115 MPCContext *c = s->priv_data;
116 int ret, size, size2, curbits, cur = c->curframe;
119 if (c->curframe >= c->fcount)
122 if(c->curframe != c->lastframe + 1){
123 url_fseek(&s->pb, c->frames[c->curframe].pos, SEEK_SET);
124 c->curbits = c->frames[c->curframe].skip;
126 c->lastframe = c->curframe;
128 curbits = c->curbits;
129 pos = url_ftell(&s->pb);
130 tmp = get_le32(&s->pb);
132 size2 = (tmp >> (12 - curbits)) & 0xFFFFF;
134 tmp = (tmp << 32) | get_le32(&s->pb);
135 size2 = (tmp >> (44 - curbits)) & 0xFFFFF;
138 url_fseek(&s->pb, pos, SEEK_SET);
140 size = ((size2 + curbits + 31) & ~31) >> 3;
141 if(cur == c->frames_noted){
142 c->frames[cur].pos = pos;
143 c->frames[cur].size = size;
144 c->frames[cur].skip = curbits - 20;
145 av_add_index_entry(s->streams[0], cur, cur, size, 0, AVINDEX_KEYFRAME);
148 c->curbits = (curbits + size2) & 0x1F;
150 if (av_new_packet(pkt, size) < 0)
153 pkt->data[0] = curbits;
154 pkt->data[1] = (c->curframe > c->fcount);
156 pkt->stream_index = 0;
158 ret = get_buffer(&s->pb, pkt->data + 4, size);
160 url_fseek(&s->pb, -4, SEEK_CUR);
170 static int mpc_read_close(AVFormatContext *s)
172 MPCContext *c = s->priv_data;
174 av_freep(&c->frames);
179 * Seek to the given position
180 * If position is unknown but is within the limits of file
181 * then packets are skipped unless desired position is reached
183 * Also this function makes use of the fact that timestamp == frameno
185 static int mpc_read_seek(AVFormatContext *s, int stream_index, int64_t timestamp, int flags)
187 AVStream *st = s->streams[stream_index];
188 MPCContext *c = s->priv_data;
189 AVPacket pkt1, *pkt = &pkt1;
191 int index = av_index_search_timestamp(st, timestamp - DELAY_FRAMES, flags);
194 /* if found, seek there */
196 c->curframe = st->index_entries[index].pos;
199 /* if timestamp is out of bounds, return error */
200 if(timestamp < 0 || timestamp >= c->fcount)
202 timestamp -= DELAY_FRAMES;
203 /* seek to the furthest known position and read packets until
204 we reach desired position */
205 lastframe = c->curframe;
206 if(c->frames_noted) c->curframe = c->frames_noted - 1;
207 while(c->curframe < timestamp){
208 ret = av_read_frame(s, pkt);
210 c->curframe = lastframe;
219 AVInputFormat mpc_demuxer = {