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ffmpeg / libavformat / ffmdec.c @ 99ed41a8

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1 de6d9b64 Fabrice Bellard
/*
2 85a6b01d Baptiste Coudurier
 * FFM (ffserver live feed) demuxer
3 406792e7 Diego Biurrun
 * Copyright (c) 2001 Fabrice Bellard
4 de6d9b64 Fabrice Bellard
 *
5 b78e7197 Diego Biurrun
 * This file is part of FFmpeg.
6
 *
7
 * FFmpeg is free software; you can redistribute it and/or
8 66d2ff2a Fabrice Bellard
 * modify it under the terms of the GNU Lesser General Public
9
 * License as published by the Free Software Foundation; either
10 b78e7197 Diego Biurrun
 * version 2.1 of the License, or (at your option) any later version.
11 de6d9b64 Fabrice Bellard
 *
12 b78e7197 Diego Biurrun
 * FFmpeg is distributed in the hope that it will be useful,
13 de6d9b64 Fabrice Bellard
 * but WITHOUT ANY WARRANTY; without even the implied warranty of
14 66d2ff2a Fabrice Bellard
 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
15
 * Lesser General Public License for more details.
16 de6d9b64 Fabrice Bellard
 *
17 66d2ff2a Fabrice Bellard
 * You should have received a copy of the GNU Lesser General Public
18 b78e7197 Diego Biurrun
 * License along with FFmpeg; if not, write to the Free Software
19 5509bffa Diego Biurrun
 * Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA
20 de6d9b64 Fabrice Bellard
 */
21 85a6b01d Baptiste Coudurier
22 6a5d31ac Diego Biurrun
#include "libavutil/intreadwrite.h"
23 de6d9b64 Fabrice Bellard
#include "avformat.h"
24 85a6b01d Baptiste Coudurier
#include "ffm.h"
25 b250f9c6 Aurelien Jacobs
#if CONFIG_FFSERVER
26 8be1c656 Fabrice Bellard
#include <unistd.h>
27 de6d9b64 Fabrice Bellard
28 bc5c918e Diego Biurrun
int64_t ffm_read_write_index(int fd)
29 278f987a Baptiste Coudurier
{
30
    uint8_t buf[8];
31
32
    lseek(fd, 8, SEEK_SET);
33
    read(fd, buf, 8);
34
    return AV_RB64(buf);
35
}
36
37 bc5c918e Diego Biurrun
void ffm_write_write_index(int fd, int64_t pos)
38 278f987a Baptiste Coudurier
{
39
    uint8_t buf[8];
40
    int i;
41
42
    for(i=0;i<8;i++)
43
        buf[i] = (pos >> (56 - i * 8)) & 0xff;
44
    lseek(fd, 8, SEEK_SET);
45
    write(fd, buf, 8);
46
}
47
48 bc5c918e Diego Biurrun
void ffm_set_write_index(AVFormatContext *s, int64_t pos, int64_t file_size)
49 278f987a Baptiste Coudurier
{
50
    FFMContext *ffm = s->priv_data;
51
    ffm->write_index = pos;
52
    ffm->file_size = file_size;
53
}
54
#endif // CONFIG_FFSERVER
55
56 de6d9b64 Fabrice Bellard
static int ffm_is_avail_data(AVFormatContext *s, int size)
57
{
58
    FFMContext *ffm = s->priv_data;
59 bc5c918e Diego Biurrun
    int64_t pos, avail_size;
60 de6d9b64 Fabrice Bellard
    int len;
61
62
    len = ffm->packet_end - ffm->packet_ptr;
63 ba26712b Baptiste Coudurier
    if (size <= len)
64
        return 1;
65 899681cd Björn Axelsson
    pos = url_ftell(s->pb);
66 de6d9b64 Fabrice Bellard
    if (pos == ffm->write_index) {
67
        /* exactly at the end of stream */
68
        return 0;
69
    } else if (pos < ffm->write_index) {
70
        avail_size = ffm->write_index - pos;
71
    } else {
72
        avail_size = (ffm->file_size - pos) + (ffm->write_index - FFM_PACKET_SIZE);
73
    }
74
    avail_size = (avail_size / ffm->packet_size) * (ffm->packet_size - FFM_HEADER_SIZE) + len;
75
    if (size <= avail_size)
76
        return 1;
77
    else
78
        return 0;
79
}
80
81
/* first is true if we read the frame header */
82 4606ac8d Zdenek Kabelac
static int ffm_read_data(AVFormatContext *s,
83 b30bb535 Baptiste Coudurier
                         uint8_t *buf, int size, int header)
84 de6d9b64 Fabrice Bellard
{
85
    FFMContext *ffm = s->priv_data;
86 899681cd Björn Axelsson
    ByteIOContext *pb = s->pb;
87 de6d9b64 Fabrice Bellard
    int len, fill_size, size1, frame_offset;
88
89
    size1 = size;
90
    while (size > 0) {
91
    redo:
92
        len = ffm->packet_end - ffm->packet_ptr;
93 e5ece183 Baptiste Coudurier
        if (len < 0)
94
            return -1;
95 de6d9b64 Fabrice Bellard
        if (len > size)
96
            len = size;
97
        if (len == 0) {
98
            if (url_ftell(pb) == ffm->file_size)
99
                url_fseek(pb, ffm->packet_size, SEEK_SET);
100 5e57424d Philip Gladstone
    retry_read:
101 de6d9b64 Fabrice Bellard
            get_be16(pb); /* PACKET_ID */
102
            fill_size = get_be16(pb);
103 fabb990e Baptiste Coudurier
            ffm->dts = get_be64(pb);
104 de6d9b64 Fabrice Bellard
            frame_offset = get_be16(pb);
105
            get_buffer(pb, ffm->packet, ffm->packet_size - FFM_HEADER_SIZE);
106
            ffm->packet_end = ffm->packet + (ffm->packet_size - FFM_HEADER_SIZE - fill_size);
107 eea2f032 Baptiste Coudurier
            if (ffm->packet_end < ffm->packet || frame_offset < 0)
108 71c32f19 Michael Niedermayer
                return -1;
109 de6d9b64 Fabrice Bellard
            /* if first packet or resynchronization packet, we must
110
               handle it specifically */
111
            if (ffm->first_packet || (frame_offset & 0x8000)) {
112 5e57424d Philip Gladstone
                if (!frame_offset) {
113
                    /* This packet has no frame headers in it */
114
                    if (url_ftell(pb) >= ffm->packet_size * 3) {
115
                        url_fseek(pb, -ffm->packet_size * 2, SEEK_CUR);
116
                        goto retry_read;
117
                    }
118
                    /* This is bad, we cannot find a valid frame header */
119
                    return 0;
120
                }
121 de6d9b64 Fabrice Bellard
                ffm->first_packet = 0;
122 a077f3bc Baptiste Coudurier
                if ((frame_offset & 0x7fff) < FFM_HEADER_SIZE)
123 71c32f19 Michael Niedermayer
                    return -1;
124 de6d9b64 Fabrice Bellard
                ffm->packet_ptr = ffm->packet + (frame_offset & 0x7fff) - FFM_HEADER_SIZE;
125 b30bb535 Baptiste Coudurier
                if (!header)
126 de6d9b64 Fabrice Bellard
                    break;
127
            } else {
128
                ffm->packet_ptr = ffm->packet;
129
            }
130
            goto redo;
131
        }
132
        memcpy(buf, ffm->packet_ptr, len);
133
        buf += len;
134
        ffm->packet_ptr += len;
135
        size -= len;
136 b30bb535 Baptiste Coudurier
        header = 0;
137 de6d9b64 Fabrice Bellard
    }
138
    return size1 - size;
139
}
140
141 4adcbbbe Baptiste Coudurier
//#define DEBUG_SEEK
142
143 a1e01307 Baptiste Coudurier
/* pos is between 0 and file_size - FFM_PACKET_SIZE. It is translated
144
   by the write position inside this function */
145 bc5c918e Diego Biurrun
static void ffm_seek1(AVFormatContext *s, int64_t pos1)
146 a1e01307 Baptiste Coudurier
{
147
    FFMContext *ffm = s->priv_data;
148
    ByteIOContext *pb = s->pb;
149 bc5c918e Diego Biurrun
    int64_t pos;
150 a1e01307 Baptiste Coudurier
151
    pos = pos1 + ffm->write_index;
152
    if (pos >= ffm->file_size)
153
        pos -= (ffm->file_size - FFM_PACKET_SIZE);
154
#ifdef DEBUG_SEEK
155 8999c833 Baptiste Coudurier
    av_log(s, AV_LOG_DEBUG, "seek to %"PRIx64" -> %"PRIx64"\n", pos1, pos);
156 a1e01307 Baptiste Coudurier
#endif
157
    url_fseek(pb, pos, SEEK_SET);
158
}
159
160 bc5c918e Diego Biurrun
static int64_t get_dts(AVFormatContext *s, int64_t pos)
161 979b1a06 Baptiste Coudurier
{
162
    ByteIOContext *pb = s->pb;
163 fabb990e Baptiste Coudurier
    int64_t dts;
164 979b1a06 Baptiste Coudurier
165
    ffm_seek1(s, pos);
166
    url_fskip(pb, 4);
167 fabb990e Baptiste Coudurier
    dts = get_be64(pb);
168 979b1a06 Baptiste Coudurier
#ifdef DEBUG_SEEK
169 8999c833 Baptiste Coudurier
    av_log(s, AV_LOG_DEBUG, "pts=%0.6f\n", pts / 1000000.0);
170 979b1a06 Baptiste Coudurier
#endif
171 fabb990e Baptiste Coudurier
    return dts;
172 979b1a06 Baptiste Coudurier
}
173 de6d9b64 Fabrice Bellard
174 91628427 Philip Gladstone
static void adjust_write_index(AVFormatContext *s)
175
{
176
    FFMContext *ffm = s->priv_data;
177 899681cd Björn Axelsson
    ByteIOContext *pb = s->pb;
178 91628427 Philip Gladstone
    int64_t pts;
179 bc5c918e Diego Biurrun
    //int64_t orig_write_index = ffm->write_index;
180
    int64_t pos_min, pos_max;
181 91628427 Philip Gladstone
    int64_t pts_start;
182 bc5c918e Diego Biurrun
    int64_t ptr = url_ftell(pb);
183 91628427 Philip Gladstone
184
185
    pos_min = 0;
186
    pos_max = ffm->file_size - 2 * FFM_PACKET_SIZE;
187
188 fabb990e Baptiste Coudurier
    pts_start = get_dts(s, pos_min);
189 91628427 Philip Gladstone
190 fabb990e Baptiste Coudurier
    pts = get_dts(s, pos_max);
191 91628427 Philip Gladstone
192 115329f1 Diego Biurrun
    if (pts - 100000 > pts_start)
193 79292510 Michael Niedermayer
        goto end;
194 91628427 Philip Gladstone
195
    ffm->write_index = FFM_PACKET_SIZE;
196
197 fabb990e Baptiste Coudurier
    pts_start = get_dts(s, pos_min);
198 91628427 Philip Gladstone
199 fabb990e Baptiste Coudurier
    pts = get_dts(s, pos_max);
200 91628427 Philip Gladstone
201
    if (pts - 100000 <= pts_start) {
202
        while (1) {
203 bc5c918e Diego Biurrun
            int64_t newpos;
204 91628427 Philip Gladstone
            int64_t newpts;
205
206
            newpos = ((pos_max + pos_min) / (2 * FFM_PACKET_SIZE)) * FFM_PACKET_SIZE;
207
208
            if (newpos == pos_min)
209
                break;
210
211 fabb990e Baptiste Coudurier
            newpts = get_dts(s, newpos);
212 91628427 Philip Gladstone
213
            if (newpts - 100000 <= pts) {
214
                pos_max = newpos;
215
                pts = newpts;
216
            } else {
217
                pos_min = newpos;
218
            }
219
        }
220
        ffm->write_index += pos_max;
221
    }
222
223 949b1a13 Steve L'Homme
    //printf("Adjusted write index from %"PRId64" to %"PRId64": pts=%0.6f\n", orig_write_index, ffm->write_index, pts / 1000000.);
224 fabb990e Baptiste Coudurier
    //printf("pts range %0.6f - %0.6f\n", get_dts(s, 0) / 1000000. , get_dts(s, ffm->file_size - 2 * FFM_PACKET_SIZE) / 1000000. );
225 91628427 Philip Gladstone
226 79292510 Michael Niedermayer
 end:
227 91628427 Philip Gladstone
    url_fseek(pb, ptr, SEEK_SET);
228
}
229
230
231 de6d9b64 Fabrice Bellard
static int ffm_read_header(AVFormatContext *s, AVFormatParameters *ap)
232
{
233 c9a65ca8 Fabrice Bellard
    FFMContext *ffm = s->priv_data;
234 de6d9b64 Fabrice Bellard
    AVStream *st;
235 899681cd Björn Axelsson
    ByteIOContext *pb = s->pb;
236 de6d9b64 Fabrice Bellard
    AVCodecContext *codec;
237 fa26a29d Fabrice Bellard
    int i, nb_streams;
238 0c1a9eda Zdenek Kabelac
    uint32_t tag;
239 de6d9b64 Fabrice Bellard
240
    /* header */
241
    tag = get_le32(pb);
242
    if (tag != MKTAG('F', 'F', 'M', '1'))
243
        goto fail;
244
    ffm->packet_size = get_be32(pb);
245
    if (ffm->packet_size != FFM_PACKET_SIZE)
246
        goto fail;
247
    ffm->write_index = get_be64(pb);
248
    /* get also filesize */
249
    if (!url_is_streamed(pb)) {
250 a965c478 Aurelien Jacobs
        ffm->file_size = url_fsize(pb);
251 91628427 Philip Gladstone
        adjust_write_index(s);
252 de6d9b64 Fabrice Bellard
    } else {
253 8da9266c Måns Rullgård
        ffm->file_size = (UINT64_C(1) << 63) - 1;
254 de6d9b64 Fabrice Bellard
    }
255
256 fa26a29d Fabrice Bellard
    nb_streams = get_be32(pb);
257 de6d9b64 Fabrice Bellard
    get_be32(pb); /* total bitrate */
258
    /* read each stream */
259 fa26a29d Fabrice Bellard
    for(i=0;i<nb_streams;i++) {
260 75bdb984 Philip Gladstone
        char rc_eq_buf[128];
261
262 fa26a29d Fabrice Bellard
        st = av_new_stream(s, 0);
263 de6d9b64 Fabrice Bellard
        if (!st)
264
            goto fail;
265 26aa0f89 Alex Beregszaszi
        s->streams[i] = st;
266 115329f1 Diego Biurrun
267 e928649b Michael Niedermayer
        av_set_pts_info(st, 64, 1, 1000000);
268 115329f1 Diego Biurrun
269 01f4895c Michael Niedermayer
        codec = st->codec;
270 de6d9b64 Fabrice Bellard
        /* generic info */
271 26aa0f89 Alex Beregszaszi
        codec->codec_id = get_be32(pb);
272
        codec->codec_type = get_byte(pb); /* codec_type */
273 de6d9b64 Fabrice Bellard
        codec->bit_rate = get_be32(pb);
274 26aa0f89 Alex Beregszaszi
        st->quality = get_be32(pb);
275 ccac2e27 Philip Gladstone
        codec->flags = get_be32(pb);
276 22332126 Philip Gladstone
        codec->flags2 = get_be32(pb);
277
        codec->debug = get_be32(pb);
278 de6d9b64 Fabrice Bellard
        /* specific info */
279
        switch(codec->codec_type) {
280
        case CODEC_TYPE_VIDEO:
281 c0df9d75 Michael Niedermayer
            codec->time_base.num = get_be32(pb);
282
            codec->time_base.den = get_be32(pb);
283 de6d9b64 Fabrice Bellard
            codec->width = get_be16(pb);
284
            codec->height = get_be16(pb);
285 20f01548 Philip Gladstone
            codec->gop_size = get_be16(pb);
286 22332126 Philip Gladstone
            codec->pix_fmt = get_be32(pb);
287 20f01548 Philip Gladstone
            codec->qmin = get_byte(pb);
288
            codec->qmax = get_byte(pb);
289
            codec->max_qdiff = get_byte(pb);
290
            codec->qcompress = get_be16(pb) / 10000.0;
291
            codec->qblur = get_be16(pb) / 10000.0;
292 3884a3c3 Philip Gladstone
            codec->bit_rate_tolerance = get_be32(pb);
293 e9a9e0c2 Fabrice Bellard
            codec->rc_eq = av_strdup(get_strz(pb, rc_eq_buf, sizeof(rc_eq_buf)));
294 75bdb984 Philip Gladstone
            codec->rc_max_rate = get_be32(pb);
295
            codec->rc_min_rate = get_be32(pb);
296
            codec->rc_buffer_size = get_be32(pb);
297 7cb8f314 Michael Niedermayer
            codec->i_quant_factor = av_int2dbl(get_be64(pb));
298
            codec->b_quant_factor = av_int2dbl(get_be64(pb));
299
            codec->i_quant_offset = av_int2dbl(get_be64(pb));
300
            codec->b_quant_offset = av_int2dbl(get_be64(pb));
301 75bdb984 Philip Gladstone
            codec->dct_algo = get_be32(pb);
302 22332126 Philip Gladstone
            codec->strict_std_compliance = get_be32(pb);
303
            codec->max_b_frames = get_be32(pb);
304
            codec->luma_elim_threshold = get_be32(pb);
305
            codec->chroma_elim_threshold = get_be32(pb);
306
            codec->mpeg_quant = get_be32(pb);
307
            codec->intra_dc_precision = get_be32(pb);
308
            codec->me_method = get_be32(pb);
309
            codec->mb_decision = get_be32(pb);
310
            codec->nsse_weight = get_be32(pb);
311
            codec->frame_skip_cmp = get_be32(pb);
312 7cb8f314 Michael Niedermayer
            codec->rc_buffer_aggressivity = av_int2dbl(get_be64(pb));
313 038a1243 Alex Beregszaszi
            codec->codec_tag = get_be32(pb);
314 dbedf2aa Baptiste Coudurier
            codec->thread_count = get_byte(pb);
315 de6d9b64 Fabrice Bellard
            break;
316
        case CODEC_TYPE_AUDIO:
317
            codec->sample_rate = get_be32(pb);
318
            codec->channels = get_le16(pb);
319 20f01548 Philip Gladstone
            codec->frame_size = get_le16(pb);
320 de6d9b64 Fabrice Bellard
            break;
321 20f01548 Philip Gladstone
        default:
322 75bdb984 Philip Gladstone
            goto fail;
323 de6d9b64 Fabrice Bellard
        }
324 7080cbe2 Baptiste Coudurier
        if (codec->flags & CODEC_FLAG_GLOBAL_HEADER) {
325
            codec->extradata_size = get_be32(pb);
326
            codec->extradata = av_malloc(codec->extradata_size);
327
            if (!codec->extradata)
328
                return AVERROR(ENOMEM);
329
            get_buffer(pb, codec->extradata, codec->extradata_size);
330
        }
331 de6d9b64 Fabrice Bellard
    }
332
333
    /* get until end of block reached */
334
    while ((url_ftell(pb) % ffm->packet_size) != 0)
335
        get_byte(pb);
336
337
    /* init packet demux */
338
    ffm->packet_ptr = ffm->packet;
339
    ffm->packet_end = ffm->packet;
340
    ffm->frame_offset = 0;
341 fabb990e Baptiste Coudurier
    ffm->dts = 0;
342 de6d9b64 Fabrice Bellard
    ffm->read_state = READ_HEADER;
343
    ffm->first_packet = 1;
344
    return 0;
345
 fail:
346
    for(i=0;i<s->nb_streams;i++) {
347
        st = s->streams[i];
348
        if (st) {
349 1ea4f593 Fabrice Bellard
            av_free(st);
350 de6d9b64 Fabrice Bellard
        }
351
    }
352
    return -1;
353
}
354
355
/* return < 0 if eof */
356
static int ffm_read_packet(AVFormatContext *s, AVPacket *pkt)
357
{
358
    int size;
359
    FFMContext *ffm = s->priv_data;
360 20f01548 Philip Gladstone
    int duration;
361 de6d9b64 Fabrice Bellard
362
    switch(ffm->read_state) {
363
    case READ_HEADER:
364 3c6a9f66 Baptiste Coudurier
        if (!ffm_is_avail_data(s, FRAME_HEADER_SIZE+4)) {
365 8fa36ae0 François Revol
            return AVERROR(EAGAIN);
366 66d2ff2a Fabrice Bellard
        }
367 ff978de4 Baptiste Coudurier
        dprintf(s, "pos=%08"PRIx64" spos=%"PRIx64", write_index=%"PRIx64" size=%"PRIx64"\n",
368 e785efc4 Albert Astals Cid
               url_ftell(s->pb), s->pb->pos, ffm->write_index, ffm->file_size);
369 115329f1 Diego Biurrun
        if (ffm_read_data(s, ffm->header, FRAME_HEADER_SIZE, 1) !=
370 66d2ff2a Fabrice Bellard
            FRAME_HEADER_SIZE)
371 8fa36ae0 François Revol
            return AVERROR(EAGAIN);
372 3c6a9f66 Baptiste Coudurier
        if (ffm->header[1] & FLAG_DTS)
373
            if (ffm_read_data(s, ffm->header+16, 4, 1) != 4)
374
                return AVERROR(EAGAIN);
375 de6d9b64 Fabrice Bellard
#if 0
376 a299832f Baptiste Coudurier
        av_hexdump_log(s, AV_LOG_DEBUG, ffm->header, FRAME_HEADER_SIZE);
377 de6d9b64 Fabrice Bellard
#endif
378
        ffm->read_state = READ_DATA;
379
        /* fall thru */
380
    case READ_DATA:
381 80fb8234 Ronald S. Bultje
        size = AV_RB24(ffm->header + 2);
382 de6d9b64 Fabrice Bellard
        if (!ffm_is_avail_data(s, size)) {
383 8fa36ae0 François Revol
            return AVERROR(EAGAIN);
384 de6d9b64 Fabrice Bellard
        }
385
386 80fb8234 Ronald S. Bultje
        duration = AV_RB24(ffm->header + 5);
387 20f01548 Philip Gladstone
388 de6d9b64 Fabrice Bellard
        av_new_packet(pkt, size);
389
        pkt->stream_index = ffm->header[0];
390 2ea2340e Baptiste Coudurier
        if ((unsigned)pkt->stream_index >= s->nb_streams) {
391
            av_log(s, AV_LOG_ERROR, "invalid stream index %d\n", pkt->stream_index);
392
            av_free_packet(pkt);
393
            ffm->read_state = READ_HEADER;
394
            return AVERROR(EAGAIN);
395
        }
396 899681cd Björn Axelsson
        pkt->pos = url_ftell(s->pb);
397 de6d9b64 Fabrice Bellard
        if (ffm->header[1] & FLAG_KEY_FRAME)
398
            pkt->flags |= PKT_FLAG_KEY;
399 4606ac8d Zdenek Kabelac
400 de6d9b64 Fabrice Bellard
        ffm->read_state = READ_HEADER;
401
        if (ffm_read_data(s, pkt->data, size, 0) != size) {
402
            /* bad case: desynchronized packet. we cancel all the packet loading */
403
            av_free_packet(pkt);
404 8fa36ae0 François Revol
            return AVERROR(EAGAIN);
405 de6d9b64 Fabrice Bellard
        }
406 3c6a9f66 Baptiste Coudurier
        pkt->pts = AV_RB64(ffm->header+8);
407
        if (ffm->header[1] & FLAG_DTS)
408
            pkt->dts = pkt->pts - AV_RB32(ffm->header+16);
409
        else
410
            pkt->dts = pkt->pts;
411 20f01548 Philip Gladstone
        pkt->duration = duration;
412 de6d9b64 Fabrice Bellard
        break;
413
    }
414
    return 0;
415
}
416
417
/* seek to a given time in the file. The file read pointer is
418 aa6b38c2 Diego Biurrun
   positioned at or before pts. XXX: the following code is quite
419 de6d9b64 Fabrice Bellard
   approximative */
420 7b3c1382 Michael Niedermayer
static int ffm_seek(AVFormatContext *s, int stream_index, int64_t wanted_pts, int flags)
421 de6d9b64 Fabrice Bellard
{
422
    FFMContext *ffm = s->priv_data;
423 bc5c918e Diego Biurrun
    int64_t pos_min, pos_max, pos;
424 0c1a9eda Zdenek Kabelac
    int64_t pts_min, pts_max, pts;
425 de6d9b64 Fabrice Bellard
    double pos1;
426
427
#ifdef DEBUG_SEEK
428 8999c833 Baptiste Coudurier
    av_log(s, AV_LOG_DEBUG, "wanted_pts=%0.6f\n", wanted_pts / 1000000.0);
429 de6d9b64 Fabrice Bellard
#endif
430
    /* find the position using linear interpolation (better than
431
       dichotomy in typical cases) */
432
    pos_min = 0;
433
    pos_max = ffm->file_size - 2 * FFM_PACKET_SIZE;
434
    while (pos_min <= pos_max) {
435 fabb990e Baptiste Coudurier
        pts_min = get_dts(s, pos_min);
436
        pts_max = get_dts(s, pos_max);
437 de6d9b64 Fabrice Bellard
        /* linear interpolation */
438 4606ac8d Zdenek Kabelac
        pos1 = (double)(pos_max - pos_min) * (double)(wanted_pts - pts_min) /
439 de6d9b64 Fabrice Bellard
            (double)(pts_max - pts_min);
440 0c1a9eda Zdenek Kabelac
        pos = (((int64_t)pos1) / FFM_PACKET_SIZE) * FFM_PACKET_SIZE;
441 de6d9b64 Fabrice Bellard
        if (pos <= pos_min)
442
            pos = pos_min;
443
        else if (pos >= pos_max)
444
            pos = pos_max;
445 fabb990e Baptiste Coudurier
        pts = get_dts(s, pos);
446 de6d9b64 Fabrice Bellard
        /* check if we are lucky */
447
        if (pts == wanted_pts) {
448
            goto found;
449
        } else if (pts > wanted_pts) {
450
            pos_max = pos - FFM_PACKET_SIZE;
451
        } else {
452
            pos_min = pos + FFM_PACKET_SIZE;
453
        }
454
    }
455 7b3c1382 Michael Niedermayer
    pos = (flags & AVSEEK_FLAG_BACKWARD) ? pos_min : pos_max;
456 de6d9b64 Fabrice Bellard
    if (pos > 0)
457
        pos -= FFM_PACKET_SIZE;
458
 found:
459
    ffm_seek1(s, pos);
460 c07d64c8 Baptiste Coudurier
461
    /* reset read state */
462
    ffm->read_state = READ_HEADER;
463
    ffm->packet_ptr = ffm->packet;
464
    ffm->packet_end = ffm->packet;
465
    ffm->first_packet = 1;
466
467 de6d9b64 Fabrice Bellard
    return 0;
468
}
469
470 07c4ed85 Philip Gladstone
static int ffm_probe(AVProbeData *p)
471
{
472 87e87886 Michael Niedermayer
    if (
473 115329f1 Diego Biurrun
        p->buf[0] == 'F' && p->buf[1] == 'F' && p->buf[2] == 'M' &&
474 66d2ff2a Fabrice Bellard
        p->buf[3] == '1')
475 07c4ed85 Philip Gladstone
        return AVPROBE_SCORE_MAX + 1;
476
    return 0;
477
}
478
479 ff70e601 Måns Rullgård
AVInputFormat ffm_demuxer = {
480 c9a65ca8 Fabrice Bellard
    "ffm",
481 af274fd1 Stefano Sabatini
    NULL_IF_CONFIG_SMALL("FFM (FFserver live feed) format"),
482 66d2ff2a Fabrice Bellard
    sizeof(FFMContext),
483 07c4ed85 Philip Gladstone
    ffm_probe,
484 c9a65ca8 Fabrice Bellard
    ffm_read_header,
485
    ffm_read_packet,
486 9f5d3b13 Baptiste Coudurier
    NULL,
487 c9a65ca8 Fabrice Bellard
    ffm_seek,
488
};