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/libavformat/mpc.c

http://github.com/FFmpeg/FFmpeg
C | 230 lines | 171 code | 26 blank | 33 comment | 42 complexity | 8992058c6543f7e45df912528b3e0c05 MD5 | raw file
  1/*
  2 * Musepack demuxer
  3 * Copyright (c) 2006 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 "libavutil/channel_layout.h"
 23
 24#include "avformat.h"
 25#include "internal.h"
 26#include "apetag.h"
 27#include "id3v1.h"
 28#include "libavutil/dict.h"
 29
 30#define MPC_FRAMESIZE  1152
 31#define DELAY_FRAMES   32
 32
 33static const int mpc_rate[4] = { 44100, 48000, 37800, 32000 };
 34typedef struct MPCFrame {
 35    int64_t pos;
 36    int size, skip;
 37}MPCFrame;
 38
 39typedef struct MPCContext {
 40    int ver;
 41    uint32_t curframe, lastframe;
 42    uint32_t fcount;
 43    MPCFrame *frames;
 44    int curbits;
 45    int frames_noted;
 46} MPCContext;
 47
 48static int mpc_probe(const AVProbeData *p)
 49{
 50    const uint8_t *d = p->buf;
 51    if (d[0] == 'M' && d[1] == 'P' && d[2] == '+' && (d[3] == 0x17 || d[3] == 0x7))
 52        return AVPROBE_SCORE_MAX;
 53    return 0;
 54}
 55
 56static int mpc_read_header(AVFormatContext *s)
 57{
 58    MPCContext *c = s->priv_data;
 59    AVStream *st;
 60    int ret;
 61
 62    if(avio_rl24(s->pb) != MKTAG('M', 'P', '+', 0)){
 63        av_log(s, AV_LOG_ERROR, "Not a Musepack file\n");
 64        return AVERROR_INVALIDDATA;
 65    }
 66    c->ver = avio_r8(s->pb);
 67    if(c->ver != 0x07 && c->ver != 0x17){
 68        av_log(s, AV_LOG_ERROR, "Can demux Musepack SV7, got version %02X\n", c->ver);
 69        return AVERROR_INVALIDDATA;
 70    }
 71    c->fcount = avio_rl32(s->pb);
 72    if((int64_t)c->fcount * sizeof(MPCFrame) >= UINT_MAX){
 73        av_log(s, AV_LOG_ERROR, "Too many frames, seeking is not possible\n");
 74        return AVERROR_INVALIDDATA;
 75    }
 76    c->curframe = 0;
 77    c->lastframe = -1;
 78    c->curbits = 8;
 79    c->frames_noted = 0;
 80
 81    st = avformat_new_stream(s, NULL);
 82    if (!st)
 83        return AVERROR(ENOMEM);
 84
 85    if (c->fcount) {
 86        c->frames = av_malloc(c->fcount * sizeof(MPCFrame));
 87        if (!c->frames) {
 88            av_log(s, AV_LOG_ERROR, "Cannot allocate seektable\n");
 89            return AVERROR(ENOMEM);
 90        }
 91        st->priv_data = c->frames;
 92    } else {
 93        av_log(s, AV_LOG_WARNING, "Container reports no frames\n");
 94    }
 95
 96    st->codecpar->codec_type = AVMEDIA_TYPE_AUDIO;
 97    st->codecpar->codec_id = AV_CODEC_ID_MUSEPACK7;
 98    st->codecpar->channels = 2;
 99    st->codecpar->channel_layout = AV_CH_LAYOUT_STEREO;
100    st->codecpar->bits_per_coded_sample = 16;
101
102    if ((ret = ff_get_extradata(s, st->codecpar, s->pb, 16)) < 0)
103        return ret;
104    st->codecpar->sample_rate = mpc_rate[st->codecpar->extradata[2] & 3];
105    avpriv_set_pts_info(st, 32, MPC_FRAMESIZE, st->codecpar->sample_rate);
106    /* scan for seekpoints */
107    st->start_time = 0;
108    st->duration = c->fcount;
109
110    /* try to read APE tags */
111    if (s->pb->seekable & AVIO_SEEKABLE_NORMAL) {
112        int64_t pos = avio_tell(s->pb);
113        ff_ape_parse_tag(s);
114        if (!av_dict_get(s->metadata, "", NULL, AV_DICT_IGNORE_SUFFIX))
115            ff_id3v1_read(s);
116        avio_seek(s->pb, pos, SEEK_SET);
117    }
118
119    return 0;
120}
121
122static int mpc_read_packet(AVFormatContext *s, AVPacket *pkt)
123{
124    MPCContext *c = s->priv_data;
125    int ret, size, size2, curbits, cur = c->curframe;
126    unsigned tmp;
127    int64_t pos;
128
129    if (c->curframe >= c->fcount && c->fcount)
130        return AVERROR_EOF;
131
132    if(c->curframe != c->lastframe + 1){
133        avio_seek(s->pb, c->frames[c->curframe].pos, SEEK_SET);
134        c->curbits = c->frames[c->curframe].skip;
135    }
136    c->lastframe = c->curframe;
137    c->curframe++;
138    curbits = c->curbits;
139    pos = avio_tell(s->pb);
140    tmp = avio_rl32(s->pb);
141    if(curbits <= 12){
142        size2 = (tmp >> (12 - curbits)) & 0xFFFFF;
143    }else{
144        size2 = (tmp << (curbits - 12) | avio_rl32(s->pb) >> (44 - curbits)) & 0xFFFFF;
145    }
146    curbits += 20;
147    avio_seek(s->pb, pos, SEEK_SET);
148
149    size = ((size2 + curbits + 31) & ~31) >> 3;
150    if(cur == c->frames_noted && c->fcount){
151        c->frames[cur].pos = pos;
152        c->frames[cur].size = size;
153        c->frames[cur].skip = curbits - 20;
154        av_add_index_entry(s->streams[0], cur, cur, size, 0, AVINDEX_KEYFRAME);
155        c->frames_noted++;
156    }
157    c->curbits = (curbits + size2) & 0x1F;
158
159    if ((ret = av_new_packet(pkt, size + 4)) < 0)
160        return ret;
161
162    pkt->data[0] = curbits;
163    pkt->data[1] = (c->curframe > c->fcount) && c->fcount;
164    pkt->data[2] = 0;
165    pkt->data[3] = 0;
166
167    pkt->stream_index = 0;
168    pkt->pts = cur;
169    ret = avio_read(s->pb, pkt->data + 4, size);
170    if(c->curbits)
171        avio_seek(s->pb, -4, SEEK_CUR);
172    if(ret < size){
173        return ret < 0 ? ret : AVERROR(EIO);
174    }
175    pkt->size = ret + 4;
176
177    return 0;
178}
179
180/**
181 * Seek to the given position
182 * If position is unknown but is within the limits of file
183 * then packets are skipped unless desired position is reached
184 *
185 * Also this function makes use of the fact that timestamp == frameno
186 */
187static int mpc_read_seek(AVFormatContext *s, int stream_index, int64_t timestamp, int flags)
188{
189    AVStream *st = s->streams[stream_index];
190    MPCContext *c = s->priv_data;
191    AVPacket pkt1, *pkt = &pkt1;
192    int ret;
193    int index = av_index_search_timestamp(st, FFMAX(timestamp - DELAY_FRAMES, 0), flags);
194    uint32_t lastframe;
195
196    /* if found, seek there */
197    if (index >= 0 && st->index_entries[st->nb_index_entries-1].timestamp >= timestamp - DELAY_FRAMES){
198        c->curframe = st->index_entries[index].pos;
199        return 0;
200    }
201    /* if timestamp is out of bounds, return error */
202    if(timestamp < 0 || timestamp >= c->fcount)
203        return -1;
204    timestamp -= DELAY_FRAMES;
205    /* seek to the furthest known position and read packets until
206       we reach desired position */
207    lastframe = c->curframe;
208    if(c->frames_noted) c->curframe = c->frames_noted - 1;
209    while(c->curframe < timestamp){
210        ret = av_read_frame(s, pkt);
211        if (ret < 0){
212            c->curframe = lastframe;
213            return ret;
214        }
215        av_packet_unref(pkt);
216    }
217    return 0;
218}
219
220
221AVInputFormat ff_mpc_demuxer = {
222    .name           = "mpc",
223    .long_name      = NULL_IF_CONFIG_SMALL("Musepack"),
224    .priv_data_size = sizeof(MPCContext),
225    .read_probe     = mpc_probe,
226    .read_header    = mpc_read_header,
227    .read_packet    = mpc_read_packet,
228    .read_seek      = mpc_read_seek,
229    .extensions     = "mpc",
230};