1/*
2 * Musepack SV8 demuxer
3 * Copyright (c) 2007 Konstantin Shishkov
4 *
5 * This file is part of FFmpeg.
6 *
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.
11 *
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.
16 *
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
20 */
21
22#include "libavcodec/bitstream.h"
23#include "libavcodec/unary.h"
24#include "avformat.h"
25
26/// Two-byte MPC tag
27#define MKMPCTAG(a, b) (a | (b << 8))
28
29#define TAG_MPCK MKTAG('M','P','C','K')
30
31/// Reserved MPC tags
32enum MPCPacketTags{
33    TAG_STREAMHDR   = MKMPCTAG('S','H'),
34    TAG_STREAMEND   = MKMPCTAG('S','E'),
35
36    TAG_AUDIOPACKET = MKMPCTAG('A','P'),
37
38    TAG_SEEKTBLOFF  = MKMPCTAG('S','O'),
39    TAG_SEEKTABLE   = MKMPCTAG('S','T'),
40
41    TAG_REPLAYGAIN  = MKMPCTAG('R','G'),
42    TAG_ENCINFO     = MKMPCTAG('E','I'),
43};
44
45static const int mpc8_rate[8] = { 44100, 48000, 37800, 32000, -1, -1, -1, -1 };
46
47typedef struct {
48    int ver;
49    int frame;
50    int64_t header_pos;
51    int64_t samples;
52} MPCContext;
53
54static int mpc8_probe(AVProbeData *p)
55{
56    if (AV_RL32(p->buf) == TAG_MPCK)
57        return AVPROBE_SCORE_MAX;
58    return 0;
59}
60
61static inline int64_t gb_get_v(GetBitContext *gb)
62{
63    int64_t v = 0;
64    int bits = 0;
65    while(get_bits1(gb) && bits < 64-7){
66        v <<= 7;
67        v |= get_bits(gb, 7);
68        bits += 7;
69    }
70    v <<= 7;
71    v |= get_bits(gb, 7);
72
73    return v;
74}
75
76static void mpc8_get_chunk_header(ByteIOContext *pb, int *tag, int64_t *size)
77{
78    int64_t pos;
79    pos = url_ftell(pb);
80    *tag = get_le16(pb);
81    *size = ff_get_v(pb);
82    *size -= url_ftell(pb) - pos;
83}
84
85static void mpc8_parse_seektable(AVFormatContext *s, int64_t off)
86{
87    MPCContext *c = s->priv_data;
88    int tag;
89    int64_t size, pos, ppos[2];
90    uint8_t *buf;
91    int i, t, seekd;
92    GetBitContext gb;
93
94    url_fseek(s->pb, off, SEEK_SET);
95    mpc8_get_chunk_header(s->pb, &tag, &size);
96    if(tag != TAG_SEEKTABLE){
97        av_log(s, AV_LOG_ERROR, "No seek table at given position\n");
98        return;
99    }
100    if(!(buf = av_malloc(size)))
101        return;
102    get_buffer(s->pb, buf, size);
103    init_get_bits(&gb, buf, size * 8);
104    size = gb_get_v(&gb);
105    if(size > UINT_MAX/4 || size > c->samples/1152){
106        av_log(s, AV_LOG_ERROR, "Seek table is too big\n");
107        return;
108    }
109    seekd = get_bits(&gb, 4);
110    for(i = 0; i < 2; i++){
111        pos = gb_get_v(&gb) + c->header_pos;
112        ppos[1 - i] = pos;
113        av_add_index_entry(s->streams[0], pos, i, 0, 0, AVINDEX_KEYFRAME);
114    }
115    for(; i < size; i++){
116        t = get_unary(&gb, 1, 33) << 12;
117        t += get_bits(&gb, 12);
118        if(t & 1)
119            t = -(t & ~1);
120        pos = (t >> 1) + ppos[0]*2 - ppos[1];
121        av_add_index_entry(s->streams[0], pos, i << seekd, 0, 0, AVINDEX_KEYFRAME);
122        ppos[1] = ppos[0];
123        ppos[0] = pos;
124    }
125    av_free(buf);
126}
127
128static void mpc8_handle_chunk(AVFormatContext *s, int tag, int64_t chunk_pos, int64_t size)
129{
130    ByteIOContext *pb = s->pb;
131    int64_t pos, off;
132
133    switch(tag){
134    case TAG_SEEKTBLOFF:
135        pos = url_ftell(pb) + size;
136        off = ff_get_v(pb);
137        mpc8_parse_seektable(s, chunk_pos + off);
138        url_fseek(pb, pos, SEEK_SET);
139        break;
140    default:
141        url_fskip(pb, size);
142    }
143}
144
145static int mpc8_read_header(AVFormatContext *s, AVFormatParameters *ap)
146{
147    MPCContext *c = s->priv_data;
148    ByteIOContext *pb = s->pb;
149    AVStream *st;
150    int tag = 0;
151    int64_t size, pos;
152
153    c->header_pos = url_ftell(pb);
154    if(get_le32(pb) != TAG_MPCK){
155        av_log(s, AV_LOG_ERROR, "Not a Musepack8 file\n");
156        return -1;
157    }
158
159    while(!url_feof(pb)){
160        pos = url_ftell(pb);
161        mpc8_get_chunk_header(pb, &tag, &size);
162        if(tag == TAG_STREAMHDR)
163            break;
164        mpc8_handle_chunk(s, tag, pos, size);
165    }
166    if(tag != TAG_STREAMHDR){
167        av_log(s, AV_LOG_ERROR, "Stream header not found\n");
168        return -1;
169    }
170    pos = url_ftell(pb);
171    url_fskip(pb, 4); //CRC
172    c->ver = get_byte(pb);
173    if(c->ver != 8){
174        av_log(s, AV_LOG_ERROR, "Unknown stream version %d\n", c->ver);
175        return -1;
176    }
177    c->samples = ff_get_v(pb);
178    ff_get_v(pb); //silence samples at the beginning
179
180    st = av_new_stream(s, 0);
181    if (!st)
182        return AVERROR(ENOMEM);
183    st->codec->codec_type = CODEC_TYPE_AUDIO;
184    st->codec->codec_id = CODEC_ID_MUSEPACK8;
185    st->codec->bits_per_coded_sample = 16;
186
187    st->codec->extradata_size = 2;
188    st->codec->extradata = av_mallocz(st->codec->extradata_size + FF_INPUT_BUFFER_PADDING_SIZE);
189    get_buffer(pb, st->codec->extradata, st->codec->extradata_size);
190
191    st->codec->channels = (st->codec->extradata[1] >> 4) + 1;
192    st->codec->sample_rate = mpc8_rate[st->codec->extradata[0] >> 5];
193    av_set_pts_info(st, 32, 1152  << (st->codec->extradata[1]&3)*2, st->codec->sample_rate);
194    st->duration = c->samples / (1152 << (st->codec->extradata[1]&3)*2);
195    size -= url_ftell(pb) - pos;
196
197    return 0;
198}
199
200static int mpc8_read_packet(AVFormatContext *s, AVPacket *pkt)
201{
202    MPCContext *c = s->priv_data;
203    int tag;
204    int64_t pos, size;
205
206    while(!url_feof(s->pb)){
207        pos = url_ftell(s->pb);
208        mpc8_get_chunk_header(s->pb, &tag, &size);
209        if(tag == TAG_AUDIOPACKET){
210            if(av_get_packet(s->pb, pkt, size) < 0)
211                return AVERROR(ENOMEM);
212            pkt->stream_index = 0;
213            pkt->pts = c->frame;
214            return 0;
215        }
216        if(tag == TAG_STREAMEND)
217            return AVERROR(EIO);
218        mpc8_handle_chunk(s, tag, pos, size);
219    }
220    return 0;
221}
222
223static int mpc8_read_seek(AVFormatContext *s, int stream_index, int64_t timestamp, int flags)
224{
225    AVStream *st = s->streams[stream_index];
226    MPCContext *c = s->priv_data;
227    int index = av_index_search_timestamp(st, timestamp, flags);
228
229    if(index < 0) return -1;
230    url_fseek(s->pb, st->index_entries[index].pos, SEEK_SET);
231    c->frame = st->index_entries[index].timestamp;
232    return 0;
233}
234
235
236AVInputFormat mpc8_demuxer = {
237    "mpc8",
238    NULL_IF_CONFIG_SMALL("Musepack SV8"),
239    sizeof(MPCContext),
240    mpc8_probe,
241    mpc8_read_header,
242    mpc8_read_packet,
243    NULL,
244    mpc8_read_seek,
245};
246