aboutsummaryrefslogtreecommitdiffstats
path: root/libavformat/internal.h
blob: 8e8971bfeba4a55f142a5d8b47ed5e9c04d35a0a (plain) (blame)
1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
50
51
52
53
54
55
56
57
58
59
60
61
62
63
64
65
66
67
68
69
70
71
72
73
74
75
76
77
78
79
80
81
82
83
84
85
86
87
88
89
90
91
92
93
94
95
96
97
98
99
100
101
102
103
104
105
106
107
108
109
110
111
112
113
114
115
116
117
118
119
120
121
122
123
124
125
126
127
128
129
130
131
132
133
134
135
136
137
138
139
140
141
142
143
144
145
146
147
148
149
150
151
152
153
154
155
156
157
158
159
160
161
162
163
164
165
166
167
168
169
170
171
172
173
174
175
176
177
178
179
180
181
182
183
184
185
186
187
188
189
190
191
192
193
194
195
196
197
198
199
200
201
202
203
204
205
206
207
208
209
210
211
212
213
214
215
216
217
218
219
220
221
222
223
224
225
226
227
228
229
230
231
232
233
234
235
236
237
238
239
240
241
242
243
244
245
246
247
248
249
250
251
252
253
254
255
256
257
258
259
260
261
262
263
264
265
266
267
268
269
270
271
272
273
274
275
276
277
278
279
280
281
282
283
284
285
286
287
288
289
290
291
292
293
294
295
296
297
298
299
300
301
302
303
304
305
306
307
308
309
310
311
312
313
314
315
316
317
318
319
320
321
322
323
324
325
326
327
328
329
330
331
332
333
334
335
336
337
338
339
340
341
342
343
344
345
346
347
348
349
350
351
352
353
354
355
356
357
358
359
360
361
362
363
364
365
366
367
368
369
370
371
372
373
374
375
376
377
378
379
380
381
382
383
384
385
386
387
388
389
390
391
392
393
394
395
396
397
398
399
400
401
402
403
404
405
406
407
408
409
410
411
412
413
414
415
416
417
418
419
420
421
422
423
424
425
426
427
428
429
430
431
432
433
434
435
436
437
438
439
440
441
442
443
444
445
446
447
448
449
450
451
452
453
454
455
456
457
458
459
460
461
462
463
464
465
466
467
468
469
470
471
472
473
474
475
476
477
478
479
480
481
482
483
484
485
486
487
488
489
490
491
492
493
494
495
496
497
498
499
500
501
502
503
504
505
506
507
508
509
510
511
512
513
514
515
516
517
518
519
520
521
522
523
524
525
526
527
528
529
530
531
532
533
534
535
536
537
538
539
540
541
542
543
544
545
546
547
548
549
550
551
552
553
554
555
556
557
558
559
560
561
562
563
564
565
566
567
568
569
570
571
572
573
574
575
576
577
578
579
580
581
582
583
584
585
586
587
588
589
590
591
592
593
594
595
596
597
598
599
600
601
602
603
604
605
606
607
608
609
610
611
612
613
614
615
616
617
618
619
620
621
622
623
624
625
626
627
628
629
630
631
632
633
634
635
636
637
638
639
640
641
642
643
644
645
646
647
648
649
650
651
652
653
654
655
656
657
658
659
660
661
662
663
664
665
666
667
668
669
670
671
672
673
674
675
676
677
678
679
680
681
682
683
684
685
686
687
688
689
690
691
692
693
694
695
696
697
698
699
700
701
702
703
704
705
706
707
708
709
710
711
712
713
714
715
716
717
718
719
720
721
722
723
724
725
726
727
728
729
730
731
732
733
734
735
736
737
738
739
740
741
742
743
744
745
746
747
748
749
750
751
752
753
/*
 * copyright (c) 2001 Fabrice Bellard
 *
 * This file is part of FFmpeg.
 *
 * FFmpeg is free software; you can redistribute it and/or
 * modify it under the terms of the GNU Lesser General Public
 * License as published by the Free Software Foundation; either
 * version 2.1 of the License, or (at your option) any later version.
 *
 * FFmpeg is distributed in the hope that it will be useful,
 * but WITHOUT ANY WARRANTY; without even the implied warranty of
 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
 * Lesser General Public License for more details.
 *
 * You should have received a copy of the GNU Lesser General Public
 * License along with FFmpeg; if not, write to the Free Software
 * Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA
 */

#ifndef AVFORMAT_INTERNAL_H
#define AVFORMAT_INTERNAL_H

#include <stdint.h>

#include "libavcodec/packet_internal.h"

#include "avformat.h"

#define MAX_URL_SIZE 4096

/** size of probe buffer, for guessing file type from file contents */
#define PROBE_BUF_MIN 2048
#define PROBE_BUF_MAX (1 << 20)

#ifdef DEBUG
#    define hex_dump_debug(class, buf, size) av_hex_dump_log(class, AV_LOG_DEBUG, buf, size)
#else
#    define hex_dump_debug(class, buf, size) do { if (0) av_hex_dump_log(class, AV_LOG_DEBUG, buf, size); } while(0)
#endif

typedef struct AVCodecTag {
    enum AVCodecID id;
    unsigned int tag;
} AVCodecTag;

typedef struct CodecMime{
    char str[32];
    enum AVCodecID id;
} CodecMime;

/*************************************************/
/* fractional numbers for exact pts handling */

/**
 * The exact value of the fractional number is: 'val + num / den'.
 * num is assumed to be 0 <= num < den.
 */
typedef struct FFFrac {
    int64_t val, num, den;
} FFFrac;


typedef struct FFFormatContext {
    /**
     * The public context.
     */
    AVFormatContext pub;

    /**
     * Number of streams relevant for interleaving.
     * Muxing only.
     */
    int nb_interleaved_streams;

    /**
     * Whether the timestamp shift offset has already been determined.
     * -1: disabled, 0: not yet determined, 1: determined.
     */
    enum {
        AVOID_NEGATIVE_TS_DISABLED = -1,
        AVOID_NEGATIVE_TS_UNKNOWN  = 0,
        AVOID_NEGATIVE_TS_KNOWN    = 1,
    } avoid_negative_ts_status;
#define AVOID_NEGATIVE_TS_ENABLED(status) ((status) >= 0)

    /**
     * The interleavement function in use. Always set for muxers.
     */
    int (*interleave_packet)(struct AVFormatContext *s, AVPacket *pkt,
                             int flush, int has_packet);

    /**
     * This buffer is only needed when packets were already buffered but
     * not decoded, for example to get the codec parameters in MPEG
     * streams.
     */
    PacketList packet_buffer;

    /* av_seek_frame() support */
    int64_t data_offset; /**< offset of the first packet */

    /**
     * Raw packets from the demuxer, prior to parsing and decoding.
     * This buffer is used for buffering packets until the codec can
     * be identified, as parsing cannot be done without knowing the
     * codec.
     */
    PacketList raw_packet_buffer;
    /**
     * Packets split by the parser get queued here.
     */
    PacketList parse_queue;
    /**
     * The generic code uses this as a temporary packet
     * to parse packets or for muxing, especially flushing.
     * For demuxers, it may also be used for other means
     * for short periods that are guaranteed not to overlap
     * with calls to av_read_frame() (or ff_read_packet())
     * or with each other.
     * It may be used by demuxers as a replacement for
     * stack packets (unless they call one of the aforementioned
     * functions with their own AVFormatContext).
     * Every user has to ensure that this packet is blank
     * after using it.
     */
    AVPacket *parse_pkt;

    /**
     * Used to hold temporary packets for the generic demuxing code.
     * When muxing, it may be used by muxers to hold packets (even
     * permanent ones).
     */
    AVPacket *pkt;
    /**
     * Sum of the size of packets in raw_packet_buffer, in bytes.
     */
    int raw_packet_buffer_size;

#if FF_API_COMPUTE_PKT_FIELDS2
    int missing_ts_warning;
#endif

#if FF_API_AVSTREAM_SIDE_DATA
    int inject_global_side_data;
#endif

    int avoid_negative_ts_use_pts;

#if FF_API_LAVF_SHORTEST
    /**
     * Timestamp of the end of the shortest stream.
     */
    int64_t shortest_end;
#endif

    /**
     * Whether or not avformat_init_output has already been called
     */
    int initialized;

    /**
     * Whether or not avformat_init_output fully initialized streams
     */
    int streams_initialized;

    /**
     * ID3v2 tag useful for MP3 demuxing
     */
    AVDictionary *id3v2_meta;

    /*
     * Prefer the codec framerate for avg_frame_rate computation.
     */
    int prefer_codec_framerate;

    /**
     * Set if chapter ids are strictly monotonic.
     */
    int chapter_ids_monotonic;

    /**
     * Contexts and child contexts do not contain a metadata option
     */
    int metafree;
} FFFormatContext;

static av_always_inline FFFormatContext *ffformatcontext(AVFormatContext *s)
{
    return (FFFormatContext*)s;
}

typedef struct FFStream {
    /**
     * The public context.
     */
    AVStream pub;

    AVFormatContext *fmtctx;
    /**
     * Set to 1 if the codec allows reordering, so pts can be different
     * from dts.
     */
    int reorder;

    /**
     * bitstream filter to run on stream
     * - encoding: Set by muxer using ff_stream_add_bitstream_filter
     * - decoding: unused
     */
    struct AVBSFContext *bsfc;

    /**
     * Whether or not check_bitstream should still be run on each packet
     */
    int bitstream_checked;

    /**
     * The codec context used by avformat_find_stream_info, the parser, etc.
     */
    struct AVCodecContext *avctx;
    /**
     * 1 if avctx has been initialized with the values from the codec parameters
     */
    int avctx_inited;

    /* the context for extracting extradata in find_stream_info()
     * inited=1/bsf=NULL signals that extracting is not possible (codec not
     * supported) */
    struct {
        struct AVBSFContext *bsf;
        int inited;
    } extract_extradata;

    /**
     * Whether the internal avctx needs to be updated from codecpar (after a late change to codecpar)
     */
    int need_context_update;

    int is_intra_only;

    FFFrac priv_pts;

    /**
     * Stream information used internally by avformat_find_stream_info()
     */
    struct FFStreamInfo *info;

    AVIndexEntry *index_entries; /**< Only used if the format does not
                                    support seeking natively. */
    int nb_index_entries;
    unsigned int index_entries_allocated_size;

    int64_t interleaver_chunk_size;
    int64_t interleaver_chunk_duration;

    /**
     * stream probing state
     * -1   -> probing finished
     *  0   -> no probing requested
     * rest -> perform probing with request_probe being the minimum score to accept.
     */
    int request_probe;
    /**
     * Indicates that everything up to the next keyframe
     * should be discarded.
     */
    int skip_to_keyframe;

    /**
     * Number of samples to skip at the start of the frame decoded from the next packet.
     */
    int skip_samples;

    /**
     * If not 0, the number of samples that should be skipped from the start of
     * the stream (the samples are removed from packets with pts==0, which also
     * assumes negative timestamps do not happen).
     * Intended for use with formats such as mp3 with ad-hoc gapless audio
     * support.
     */
    int64_t start_skip_samples;

    /**
     * If not 0, the first audio sample that should be discarded from the stream.
     * This is broken by design (needs global sample count), but can't be
     * avoided for broken by design formats such as mp3 with ad-hoc gapless
     * audio support.
     */
    int64_t first_discard_sample;

    /**
     * The sample after last sample that is intended to be discarded after
     * first_discard_sample. Works on frame boundaries only. Used to prevent
     * early EOF if the gapless info is broken (considered concatenated mp3s).
     */
    int64_t last_discard_sample;

    /**
     * Number of internally decoded frames, used internally in libavformat, do not access
     * its lifetime differs from info which is why it is not in that structure.
     */
    int nb_decoded_frames;

    /**
     * Timestamp offset added to timestamps before muxing
     */
    int64_t mux_ts_offset;

    /**
     * This is the lowest ts allowed in this track; it may be set by the muxer
     * during init or write_header and influences the automatic timestamp
     * shifting code.
     */
    int64_t lowest_ts_allowed;

    /**
     * Internal data to check for wrapping of the time stamp
     */
    int64_t pts_wrap_reference;

    /**
     * Options for behavior, when a wrap is detected.
     *
     * Defined by AV_PTS_WRAP_ values.
     *
     * If correction is enabled, there are two possibilities:
     * If the first time stamp is near the wrap point, the wrap offset
     * will be subtracted, which will create negative time stamps.
     * Otherwise the offset will be added.
     */
    int pts_wrap_behavior;

    /**
     * Internal data to prevent doing update_initial_durations() twice
     */
    int update_initial_durations_done;

#define MAX_REORDER_DELAY 16

    /**
     * Internal data to generate dts from pts
     */
    int64_t pts_reorder_error[MAX_REORDER_DELAY+1];
    uint8_t pts_reorder_error_count[MAX_REORDER_DELAY+1];

    int64_t pts_buffer[MAX_REORDER_DELAY+1];

    /**
     * Internal data to analyze DTS and detect faulty mpeg streams
     */
    int64_t last_dts_for_order_check;
    uint8_t dts_ordered;
    uint8_t dts_misordered;

#if FF_API_AVSTREAM_SIDE_DATA
    /**
     * Internal data to inject global side data
     */
    int inject_global_side_data;
#endif

    /**
     * display aspect ratio (0 if unknown)
     * - encoding: unused
     * - decoding: Set by libavformat to calculate sample_aspect_ratio internally
     */
    AVRational display_aspect_ratio;

    AVProbeData probe_data;

    /**
     * last packet in packet_buffer for this stream when muxing.
     */
    PacketListEntry *last_in_packet_buffer;

    int64_t last_IP_pts;
    int last_IP_duration;

    /**
     * Number of packets to buffer for codec probing
     */
    int probe_packets;

    /* av_read_frame() support */
    enum AVStreamParseType need_parsing;
    struct AVCodecParserContext *parser;

    /**
     * Number of frames that have been demuxed during avformat_find_stream_info()
     */
    int codec_info_nb_frames;

    /**
     * Stream Identifier
     * This is the MPEG-TS stream identifier +1
     * 0 means unknown
     */
    int stream_identifier;

    // Timestamp generation support:
    /**
     * Timestamp corresponding to the last dts sync point.
     *
     * Initialized when AVCodecParserContext.dts_sync_point >= 0 and
     * a DTS is received from the underlying container. Otherwise set to
     * AV_NOPTS_VALUE by default.
     */
    int64_t first_dts;
    int64_t cur_dts;

    const struct AVCodecDescriptor *codec_desc;

#if FF_API_INTERNAL_TIMING
    AVRational transferred_mux_tb;
#endif
} FFStream;

static av_always_inline FFStream *ffstream(AVStream *st)
{
    return (FFStream*)st;
}

static av_always_inline const FFStream *cffstream(const AVStream *st)
{
    return (const FFStream*)st;
}

typedef struct FFStreamGroup {
    /**
     * The public context.
     */
    AVStreamGroup pub;

    AVFormatContext *fmtctx;
} FFStreamGroup;


static av_always_inline FFStreamGroup *ffstreamgroup(AVStreamGroup *stg)
{
    return (FFStreamGroup*)stg;
}

static av_always_inline const FFStreamGroup *cffstreamgroup(const AVStreamGroup *stg)
{
    return (const FFStreamGroup*)stg;
}

#ifdef __GNUC__
#define dynarray_add(tab, nb_ptr, elem)\
do {\
    __typeof__(tab) _tab = (tab);\
    __typeof__(elem) _elem = (elem);\
    (void)sizeof(**_tab == _elem); /* check that types are compatible */\
    av_dynarray_add(_tab, nb_ptr, _elem);\
} while(0)
#else
#define dynarray_add(tab, nb_ptr, elem)\
do {\
    av_dynarray_add((tab), nb_ptr, (elem));\
} while(0)
#endif


void ff_flush_packet_queue(AVFormatContext *s);

/**
 * Automatically create sub-directories
 *
 * @param path will create sub-directories by path
 * @return 0, or < 0 on error
 */
int ff_mkdir_p(const char *path);

/**
 * Write hexadecimal string corresponding to given binary data. The string
 * is zero-terminated.
 *
 * @param buf       the output string is written here;
 *                  needs to be at least 2 * size + 1 bytes long.
 * @param src       the input data to be transformed.
 * @param size      the size (in byte) of src.
 * @param lowercase determines whether to use the range [0-9a-f] or [0-9A-F].
 * @return buf.
 */
char *ff_data_to_hex(char *buf, const uint8_t *src, int size, int lowercase);

/**
 * Parse a string of hexadecimal strings. Any space between the hexadecimal
 * digits is ignored.
 *
 * @param data if non-null, the parsed data is written to this pointer
 * @param p the string to parse
 * @return the number of bytes written (or to be written, if data is null)
 */
int ff_hex_to_data(uint8_t *data, const char *p);

#define NTP_OFFSET 2208988800ULL
#define NTP_OFFSET_US (NTP_OFFSET * 1000000ULL)

/** Get the current time since NTP epoch in microseconds. */
uint64_t ff_ntp_time(void);

/**
 * Get the NTP time stamp formatted as per the RFC-5905.
 *
 * @param ntp_time NTP time in micro seconds (since NTP epoch)
 * @return the formatted NTP time stamp
 */
uint64_t ff_get_formatted_ntp_time(uint64_t ntp_time_us);

/**
 * Parse the NTP time in micro seconds (since NTP epoch).
 *
 * @param ntp_ts NTP time stamp formatted as per the RFC-5905.
 * @return the time in micro seconds (since NTP epoch)
 */
uint64_t ff_parse_ntp_time(uint64_t ntp_ts);

/**
 * Append the media-specific SDP fragment for the media stream c
 * to the buffer buff.
 *
 * Note, the buffer needs to be initialized, since it is appended to
 * existing content.
 *
 * @param buff the buffer to append the SDP fragment to
 * @param size the size of the buff buffer
 * @param st the AVStream of the media to describe
 * @param idx the global stream index
 * @param dest_addr the destination address of the media stream, may be NULL
 * @param dest_type the destination address type, may be NULL
 * @param port the destination port of the media stream, 0 if unknown
 * @param ttl the time to live of the stream, 0 if not multicast
 * @param fmt the AVFormatContext, which might contain options modifying
 *            the generated SDP
 * @return 0 on success, a negative error code on failure
 */
int ff_sdp_write_media(char *buff, int size, const AVStream *st, int idx,
                       const char *dest_addr, const char *dest_type,
                       int port, int ttl, AVFormatContext *fmt);

/**
 * Read a whole line of text from AVIOContext. Stop reading after reaching
 * either a \\n, a \\0 or EOF. The returned string is always \\0-terminated,
 * and may be truncated if the buffer is too small.
 *
 * @param s the read-only AVIOContext
 * @param buf buffer to store the read line
 * @param maxlen size of the buffer
 * @return the length of the string written in the buffer, not including the
 *         final \\0
 */
int ff_get_line(AVIOContext *s, char *buf, int maxlen);

/**
 * Same as ff_get_line but strip the white-space characters in the text tail
 *
 * @param s the read-only AVIOContext
 * @param buf buffer to store the read line
 * @param maxlen size of the buffer
 * @return the length of the string written in the buffer
 */
int ff_get_chomp_line(AVIOContext *s, char *buf, int maxlen);

#define SPACE_CHARS " \t\r\n"

/**
 * Callback function type for ff_parse_key_value.
 *
 * @param key a pointer to the key
 * @param key_len the number of bytes that belong to the key, including the '='
 *                char
 * @param dest return the destination pointer for the value in *dest, may
 *             be null to ignore the value
 * @param dest_len the length of the *dest buffer
 */
typedef void (*ff_parse_key_val_cb)(void *context, const char *key,
                                    int key_len, char **dest, int *dest_len);
/**
 * Parse a string with comma-separated key=value pairs. The value strings
 * may be quoted and may contain escaped characters within quoted strings.
 *
 * @param str the string to parse
 * @param callback_get_buf function that returns where to store the
 *                         unescaped value string.
 * @param context the opaque context pointer to pass to callback_get_buf
 */
void ff_parse_key_value(const char *str, ff_parse_key_val_cb callback_get_buf,
                        void *context);

enum AVCodecID ff_guess_image2_codec(const char *filename);

const struct AVCodec *ff_find_decoder(AVFormatContext *s, const AVStream *st,
                                      enum AVCodecID codec_id);

/**
 * Set the time base and wrapping info for a given stream. This will be used
 * to interpret the stream's timestamps. If the new time base is invalid
 * (numerator or denominator are non-positive), it leaves the stream
 * unchanged.
 *
 * @param st stream
 * @param pts_wrap_bits number of bits effectively used by the pts
 *        (used for wrap control)
 * @param pts_num time base numerator
 * @param pts_den time base denominator
 */
void avpriv_set_pts_info(AVStream *st, int pts_wrap_bits,
                         unsigned int pts_num, unsigned int pts_den);

/**
 * Set the timebase for each stream from the corresponding codec timebase and
 * print it.
 */
int ff_framehash_write_header(AVFormatContext *s);

/**
 * Frees a stream without modifying the corresponding AVFormatContext.
 * Must only be called if the latter doesn't matter or if the stream
 * is not yet attached to an AVFormatContext.
 */
void ff_free_stream(AVStream **st);
/**
 * Remove a stream from its AVFormatContext and free it.
 * The stream must be the last stream of the AVFormatContext.
 */
void ff_remove_stream(AVFormatContext *s, AVStream *st);

/**
 * Frees a stream group without modifying the corresponding AVFormatContext.
 * Must only be called if the latter doesn't matter or if the stream
 * is not yet attached to an AVFormatContext.
 */
void ff_free_stream_group(AVStreamGroup **pstg);
/**
 * Remove a stream group from its AVFormatContext and free it.
 * The stream group must be the last stream group of the AVFormatContext.
 */
void ff_remove_stream_group(AVFormatContext *s, AVStreamGroup *stg);

unsigned int ff_codec_get_tag(const AVCodecTag *tags, enum AVCodecID id);

enum AVCodecID ff_codec_get_id(const AVCodecTag *tags, unsigned int tag);

int ff_is_intra_only(enum AVCodecID id);

/**
 * Select a PCM codec based on the given parameters.
 *
 * @param bps     bits-per-sample
 * @param flt     floating-point
 * @param be      big-endian
 * @param sflags  signed flags. each bit corresponds to one byte of bit depth.
 *                e.g. the 1st bit indicates if 8-bit should be signed or
 *                unsigned, the 2nd bit indicates if 16-bit should be signed or
 *                unsigned, etc... This is useful for formats such as WAVE where
 *                only 8-bit is unsigned and all other bit depths are signed.
 * @return        a PCM codec id or AV_CODEC_ID_NONE
 */
enum AVCodecID ff_get_pcm_codec_id(int bps, int flt, int be, int sflags);

/**
 * Copy side data from source to destination stream
 *
 * @param dst pointer to destination AVStream
 * @param src pointer to source AVStream
 * @return >=0 on success, AVERROR code on error
 */
int ff_stream_side_data_copy(AVStream *dst, const AVStream *src);

/**
 * Create a new stream and copy to it all parameters from a source stream, with
 * the exception of the index field, which is set when the new stream is
 * created.
 *
 * @param dst_ctx pointer to the context in which the new stream is created
 * @param src pointer to source AVStream
 * @return pointer to the new stream or NULL on error
 */
AVStream *ff_stream_clone(AVFormatContext *dst_ctx, const AVStream *src);

/**
 * Wrap ffurl_move() and log if error happens.
 *
 * @param url_src source path
 * @param url_dst destination path
 * @return        0 or AVERROR on failure
 */
int ff_rename(const char *url_src, const char *url_dst, void *logctx);

/**
 * Allocate extradata with additional AV_INPUT_BUFFER_PADDING_SIZE at end
 * which is always set to 0.
 *
 * Previously allocated extradata in par will be freed.
 *
 * @param size size of extradata
 * @return 0 if OK, AVERROR_xxx on error
 */
int ff_alloc_extradata(AVCodecParameters *par, int size);

/**
 * Copies the whilelists from one context to the other
 */
int ff_copy_whiteblacklists(AVFormatContext *dst, const AVFormatContext *src);

/*
 * A wrapper around AVFormatContext.io_close that should be used
 * instead of calling the pointer directly.
 *
 * @param s AVFormatContext
 * @param *pb the AVIOContext to be closed and freed. Can be NULL.
 * @return >=0 on success, negative AVERROR in case of failure
 */
int ff_format_io_close(AVFormatContext *s, AVIOContext **pb);

/**
 * Utility function to check if the file uses http or https protocol
 *
 * @param s AVFormatContext
 * @param filename URL or file name to open for writing
 */
int ff_is_http_proto(const char *filename);

struct AVBPrint;
/**
 * Finalize buf into extradata and set its size appropriately.
 */
int ff_bprint_to_codecpar_extradata(AVCodecParameters *par, struct AVBPrint *buf);

/**
 * Set AVFormatContext url field to the provided pointer. The pointer must
 * point to a valid string. The existing url field is freed if necessary. Also
 * set the legacy filename field to the same string which was provided in url.
 */
void ff_format_set_url(AVFormatContext *s, char *url);

/**
 * Return a positive value if the given url has one of the given
 * extensions, negative AVERROR on error, 0 otherwise.
 *
 * @param url        url to check against the given extensions
 * @param extensions a comma-separated list of filename extensions
 */
int ff_match_url_ext(const char *url, const char *extensions);

struct FFOutputFormat;
struct FFInputFormat;
void avpriv_register_devices(const struct FFOutputFormat * const o[],
                             const struct FFInputFormat * const i[]);

#endif /* AVFORMAT_INTERNAL_H */