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1 /*
2  * copyright (c) 2001 Fabrice Bellard
3  *
4  * This file is part of FFmpeg.
5  *
6  * FFmpeg is free software; you can redistribute it and/or
7  * modify it under the terms of the GNU Lesser General Public
8  * License as published by the Free Software Foundation; either
9  * version 2.1 of the License, or (at your option) any later version.
10  *
11  * FFmpeg is distributed in the hope that it will be useful,
12  * but WITHOUT ANY WARRANTY; without even the implied warranty of
13  * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
14  * Lesser General Public License for more details.
15  *
16  * You should have received a copy of the GNU Lesser General Public
17  * License along with FFmpeg; if not, write to the Free Software
18  * Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA
19  */
20 
21 #ifndef AVFORMAT_INTERNAL_H
22 #define AVFORMAT_INTERNAL_H
23 
24 #include <stdint.h>
25 
26 #include "libavcodec/avcodec.h"
27 #include "libavcodec/packet_internal.h"
28 
29 #include "avformat.h"
30 #include "os_support.h"
31 
32 #define MAX_URL_SIZE 4096
33 
34 /** size of probe buffer, for guessing file type from file contents */
35 #define PROBE_BUF_MIN 2048
36 #define PROBE_BUF_MAX (1 << 20)
37 
38 #ifdef DEBUG
39 #    define hex_dump_debug(class, buf, size) av_hex_dump_log(class, AV_LOG_DEBUG, buf, size)
40 #else
41 #    define hex_dump_debug(class, buf, size) do { if (0) av_hex_dump_log(class, AV_LOG_DEBUG, buf, size); } while(0)
42 #endif
43 
44 /**
45  * For an AVInputFormat with this flag set read_close() needs to be called
46  * by the caller upon read_header() failure.
47  */
48 #define FF_FMT_INIT_CLEANUP                             (1 << 0)
49 
50 typedef struct AVCodecTag {
51     enum AVCodecID id;
52     unsigned int tag;
53 } AVCodecTag;
54 
55 typedef struct CodecMime{
56     char str[32];
57     enum AVCodecID id;
58 } CodecMime;
59 
60 /*************************************************/
61 /* fractional numbers for exact pts handling */
62 
63 /**
64  * The exact value of the fractional number is: 'val + num / den'.
65  * num is assumed to be 0 <= num < den.
66  */
67 typedef struct FFFrac {
68     int64_t val, num, den;
69 } FFFrac;
70 
71 
72 typedef struct FFFormatContext {
73     /**
74      * The public context.
75      */
76     AVFormatContext pub;
77 
78     /**
79      * Number of streams relevant for interleaving.
80      * Muxing only.
81      */
82     int nb_interleaved_streams;
83 
84     /**
85      * Whether the timestamp shift offset has already been determined.
86      * -1: disabled, 0: not yet determined, 1: determined.
87      */
88     enum {
89         AVOID_NEGATIVE_TS_DISABLED = -1,
90         AVOID_NEGATIVE_TS_UNKNOWN  = 0,
91         AVOID_NEGATIVE_TS_KNOWN    = 1,
92     } avoid_negative_ts_status;
93 #define AVOID_NEGATIVE_TS_ENABLED(status) ((status) >= 0)
94 
95     /**
96      * The interleavement function in use. Always set for muxers.
97      */
98     int (*interleave_packet)(struct AVFormatContext *s, AVPacket *pkt,
99                              int flush, int has_packet);
100 
101     /**
102      * This buffer is only needed when packets were already buffered but
103      * not decoded, for example to get the codec parameters in MPEG
104      * streams.
105      */
106     PacketList packet_buffer;
107 
108     /* av_seek_frame() support */
109     int64_t data_offset; /**< offset of the first packet */
110 
111     /**
112      * Raw packets from the demuxer, prior to parsing and decoding.
113      * This buffer is used for buffering packets until the codec can
114      * be identified, as parsing cannot be done without knowing the
115      * codec.
116      */
117     PacketList raw_packet_buffer;
118     /**
119      * Packets split by the parser get queued here.
120      */
121     PacketList parse_queue;
122     /**
123      * The generic code uses this as a temporary packet
124      * to parse packets or for muxing, especially flushing.
125      * For demuxers, it may also be used for other means
126      * for short periods that are guaranteed not to overlap
127      * with calls to av_read_frame() (or ff_read_packet())
128      * or with each other.
129      * It may be used by demuxers as a replacement for
130      * stack packets (unless they call one of the aforementioned
131      * functions with their own AVFormatContext).
132      * Every user has to ensure that this packet is blank
133      * after using it.
134      */
135     AVPacket *parse_pkt;
136 
137     /**
138      * Used to hold temporary packets for the generic demuxing code.
139      * When muxing, it may be used by muxers to hold packets (even
140      * permanent ones).
141      */
142     AVPacket *pkt;
143     /**
144      * Sum of the size of packets in raw_packet_buffer, in bytes.
145      */
146     int raw_packet_buffer_size;
147 
148 #if FF_API_COMPUTE_PKT_FIELDS2
149     int missing_ts_warning;
150 #endif
151 
152     int inject_global_side_data;
153 
154     int avoid_negative_ts_use_pts;
155 
156     /**
157      * Timestamp of the end of the shortest stream.
158      */
159     int64_t shortest_end;
160 
161     /**
162      * Whether or not avformat_init_output has already been called
163      */
164     int initialized;
165 
166     /**
167      * Whether or not avformat_init_output fully initialized streams
168      */
169     int streams_initialized;
170 
171     /**
172      * ID3v2 tag useful for MP3 demuxing
173      */
174     AVDictionary *id3v2_meta;
175 
176     /*
177      * Prefer the codec framerate for avg_frame_rate computation.
178      */
179     int prefer_codec_framerate;
180 
181     /**
182      * Set if chapter ids are strictly monotonic.
183      */
184     int chapter_ids_monotonic;
185 
186     /**
187      * Contexts and child contexts do not contain a metadata option
188      */
189     int metafree;
190 } FFFormatContext;
191 
ffformatcontext(AVFormatContext * s)192 static av_always_inline FFFormatContext *ffformatcontext(AVFormatContext *s)
193 {
194     return (FFFormatContext*)s;
195 }
196 
197 typedef struct FFStream {
198     /**
199      * The public context.
200      */
201     AVStream pub;
202 
203     /**
204      * Set to 1 if the codec allows reordering, so pts can be different
205      * from dts.
206      */
207     int reorder;
208 
209     /**
210      * bitstream filter to run on stream
211      * - encoding: Set by muxer using ff_stream_add_bitstream_filter
212      * - decoding: unused
213      */
214     struct AVBSFContext *bsfc;
215 
216     /**
217      * Whether or not check_bitstream should still be run on each packet
218      */
219     int bitstream_checked;
220 
221     /**
222      * The codec context used by avformat_find_stream_info, the parser, etc.
223      */
224     AVCodecContext *avctx;
225     /**
226      * 1 if avctx has been initialized with the values from the codec parameters
227      */
228     int avctx_inited;
229 
230     /* the context for extracting extradata in find_stream_info()
231      * inited=1/bsf=NULL signals that extracting is not possible (codec not
232      * supported) */
233     struct {
234         struct AVBSFContext *bsf;
235         int inited;
236     } extract_extradata;
237 
238     /**
239      * Whether the internal avctx needs to be updated from codecpar (after a late change to codecpar)
240      */
241     int need_context_update;
242 
243     int is_intra_only;
244 
245     FFFrac *priv_pts;
246 
247     /**
248      * Stream information used internally by avformat_find_stream_info()
249      */
250     struct FFStreamInfo *info;
251 
252     AVIndexEntry *index_entries; /**< Only used if the format does not
253                                     support seeking natively. */
254     int nb_index_entries;
255     unsigned int index_entries_allocated_size;
256 
257     int64_t interleaver_chunk_size;
258     int64_t interleaver_chunk_duration;
259 
260     /**
261      * stream probing state
262      * -1   -> probing finished
263      *  0   -> no probing requested
264      * rest -> perform probing with request_probe being the minimum score to accept.
265      */
266     int request_probe;
267     /**
268      * Indicates that everything up to the next keyframe
269      * should be discarded.
270      */
271     int skip_to_keyframe;
272 
273     /**
274      * Number of samples to skip at the start of the frame decoded from the next packet.
275      */
276     int skip_samples;
277 
278     /**
279      * If not 0, the number of samples that should be skipped from the start of
280      * the stream (the samples are removed from packets with pts==0, which also
281      * assumes negative timestamps do not happen).
282      * Intended for use with formats such as mp3 with ad-hoc gapless audio
283      * support.
284      */
285     int64_t start_skip_samples;
286 
287     /**
288      * If not 0, the first audio sample that should be discarded from the stream.
289      * This is broken by design (needs global sample count), but can't be
290      * avoided for broken by design formats such as mp3 with ad-hoc gapless
291      * audio support.
292      */
293     int64_t first_discard_sample;
294 
295     /**
296      * The sample after last sample that is intended to be discarded after
297      * first_discard_sample. Works on frame boundaries only. Used to prevent
298      * early EOF if the gapless info is broken (considered concatenated mp3s).
299      */
300     int64_t last_discard_sample;
301 
302     /**
303      * Number of internally decoded frames, used internally in libavformat, do not access
304      * its lifetime differs from info which is why it is not in that structure.
305      */
306     int nb_decoded_frames;
307 
308     /**
309      * Timestamp offset added to timestamps before muxing
310      */
311     int64_t mux_ts_offset;
312 
313     /**
314      * Internal data to check for wrapping of the time stamp
315      */
316     int64_t pts_wrap_reference;
317 
318     /**
319      * Options for behavior, when a wrap is detected.
320      *
321      * Defined by AV_PTS_WRAP_ values.
322      *
323      * If correction is enabled, there are two possibilities:
324      * If the first time stamp is near the wrap point, the wrap offset
325      * will be subtracted, which will create negative time stamps.
326      * Otherwise the offset will be added.
327      */
328     int pts_wrap_behavior;
329 
330     /**
331      * Internal data to prevent doing update_initial_durations() twice
332      */
333     int update_initial_durations_done;
334 
335 #define MAX_REORDER_DELAY 16
336 
337     /**
338      * Internal data to generate dts from pts
339      */
340     int64_t pts_reorder_error[MAX_REORDER_DELAY+1];
341     uint8_t pts_reorder_error_count[MAX_REORDER_DELAY+1];
342 
343     int64_t pts_buffer[MAX_REORDER_DELAY+1];
344 
345     /**
346      * Internal data to analyze DTS and detect faulty mpeg streams
347      */
348     int64_t last_dts_for_order_check;
349     uint8_t dts_ordered;
350     uint8_t dts_misordered;
351 
352     /**
353      * Internal data to inject global side data
354      */
355     int inject_global_side_data;
356 
357     /**
358      * display aspect ratio (0 if unknown)
359      * - encoding: unused
360      * - decoding: Set by libavformat to calculate sample_aspect_ratio internally
361      */
362     AVRational display_aspect_ratio;
363 
364     AVProbeData probe_data;
365 
366     /**
367      * last packet in packet_buffer for this stream when muxing.
368      */
369     PacketListEntry *last_in_packet_buffer;
370 
371     int64_t last_IP_pts;
372     int last_IP_duration;
373 
374     /**
375      * Number of packets to buffer for codec probing
376      */
377     int probe_packets;
378 
379     /* av_read_frame() support */
380     enum AVStreamParseType need_parsing;
381     struct AVCodecParserContext *parser;
382 
383     /**
384      * Number of frames that have been demuxed during avformat_find_stream_info()
385      */
386     int codec_info_nb_frames;
387 
388     /**
389      * Stream Identifier
390      * This is the MPEG-TS stream identifier +1
391      * 0 means unknown
392      */
393     int stream_identifier;
394 
395     // Timestamp generation support:
396     /**
397      * Timestamp corresponding to the last dts sync point.
398      *
399      * Initialized when AVCodecParserContext.dts_sync_point >= 0 and
400      * a DTS is received from the underlying container. Otherwise set to
401      * AV_NOPTS_VALUE by default.
402      */
403     int64_t first_dts;
404     int64_t cur_dts;
405 } FFStream;
406 
ffstream(AVStream * st)407 static av_always_inline FFStream *ffstream(AVStream *st)
408 {
409     return (FFStream*)st;
410 }
411 
cffstream(const AVStream * st)412 static av_always_inline const FFStream *cffstream(const AVStream *st)
413 {
414     return (FFStream*)st;
415 }
416 
417 #ifdef __GNUC__
418 #define dynarray_add(tab, nb_ptr, elem)\
419 do {\
420     __typeof__(tab) _tab = (tab);\
421     __typeof__(elem) _elem = (elem);\
422     (void)sizeof(**_tab == _elem); /* check that types are compatible */\
423     av_dynarray_add(_tab, nb_ptr, _elem);\
424 } while(0)
425 #else
426 #define dynarray_add(tab, nb_ptr, elem)\
427 do {\
428     av_dynarray_add((tab), nb_ptr, (elem));\
429 } while(0)
430 #endif
431 
432 
433 void ff_flush_packet_queue(AVFormatContext *s);
434 
435 /**
436  * Automatically create sub-directories
437  *
438  * @param path will create sub-directories by path
439  * @return 0, or < 0 on error
440  */
441 int ff_mkdir_p(const char *path);
442 
443 /**
444  * Write hexadecimal string corresponding to given binary data. The string
445  * is zero-terminated.
446  *
447  * @param buf       the output string is written here;
448  *                  needs to be at least 2 * size + 1 bytes long.
449  * @param src       the input data to be transformed.
450  * @param size      the size (in byte) of src.
451  * @param lowercase determines whether to use the range [0-9a-f] or [0-9A-F].
452  * @return buf.
453  */
454 char *ff_data_to_hex(char *buf, const uint8_t *src, int size, int lowercase);
455 
456 /**
457  * Parse a string of hexadecimal strings. Any space between the hexadecimal
458  * digits is ignored.
459  *
460  * @param data if non-null, the parsed data is written to this pointer
461  * @param p the string to parse
462  * @return the number of bytes written (or to be written, if data is null)
463  */
464 int ff_hex_to_data(uint8_t *data, const char *p);
465 
466 #define NTP_OFFSET 2208988800ULL
467 #define NTP_OFFSET_US (NTP_OFFSET * 1000000ULL)
468 
469 /** Get the current time since NTP epoch in microseconds. */
470 uint64_t ff_ntp_time(void);
471 
472 /**
473  * Get the NTP time stamp formatted as per the RFC-5905.
474  *
475  * @param ntp_time NTP time in micro seconds (since NTP epoch)
476  * @return the formatted NTP time stamp
477  */
478 uint64_t ff_get_formatted_ntp_time(uint64_t ntp_time_us);
479 
480 /**
481  * Parse the NTP time in micro seconds (since NTP epoch).
482  *
483  * @param ntp_ts NTP time stamp formatted as per the RFC-5905.
484  * @return the time in micro seconds (since NTP epoch)
485  */
486 uint64_t ff_parse_ntp_time(uint64_t ntp_ts);
487 
488 /**
489  * Append the media-specific SDP fragment for the media stream c
490  * to the buffer buff.
491  *
492  * Note, the buffer needs to be initialized, since it is appended to
493  * existing content.
494  *
495  * @param buff the buffer to append the SDP fragment to
496  * @param size the size of the buff buffer
497  * @param st the AVStream of the media to describe
498  * @param idx the global stream index
499  * @param dest_addr the destination address of the media stream, may be NULL
500  * @param dest_type the destination address type, may be NULL
501  * @param port the destination port of the media stream, 0 if unknown
502  * @param ttl the time to live of the stream, 0 if not multicast
503  * @param fmt the AVFormatContext, which might contain options modifying
504  *            the generated SDP
505  * @return 0 on success, a negative error code on failure
506  */
507 int ff_sdp_write_media(char *buff, int size, const AVStream *st, int idx,
508                        const char *dest_addr, const char *dest_type,
509                        int port, int ttl, AVFormatContext *fmt);
510 
511 /**
512  * Read a whole line of text from AVIOContext. Stop reading after reaching
513  * either a \\n, a \\0 or EOF. The returned string is always \\0-terminated,
514  * and may be truncated if the buffer is too small.
515  *
516  * @param s the read-only AVIOContext
517  * @param buf buffer to store the read line
518  * @param maxlen size of the buffer
519  * @return the length of the string written in the buffer, not including the
520  *         final \\0
521  */
522 int ff_get_line(AVIOContext *s, char *buf, int maxlen);
523 
524 /**
525  * Same as ff_get_line but strip the white-space characters in the text tail
526  *
527  * @param s the read-only AVIOContext
528  * @param buf buffer to store the read line
529  * @param maxlen size of the buffer
530  * @return the length of the string written in the buffer
531  */
532 int ff_get_chomp_line(AVIOContext *s, char *buf, int maxlen);
533 
534 #define SPACE_CHARS " \t\r\n"
535 
536 /**
537  * Callback function type for ff_parse_key_value.
538  *
539  * @param key a pointer to the key
540  * @param key_len the number of bytes that belong to the key, including the '='
541  *                char
542  * @param dest return the destination pointer for the value in *dest, may
543  *             be null to ignore the value
544  * @param dest_len the length of the *dest buffer
545  */
546 typedef void (*ff_parse_key_val_cb)(void *context, const char *key,
547                                     int key_len, char **dest, int *dest_len);
548 /**
549  * Parse a string with comma-separated key=value pairs. The value strings
550  * may be quoted and may contain escaped characters within quoted strings.
551  *
552  * @param str the string to parse
553  * @param callback_get_buf function that returns where to store the
554  *                         unescaped value string.
555  * @param context the opaque context pointer to pass to callback_get_buf
556  */
557 void ff_parse_key_value(const char *str, ff_parse_key_val_cb callback_get_buf,
558                         void *context);
559 
560 enum AVCodecID ff_guess_image2_codec(const char *filename);
561 
562 const AVCodec *ff_find_decoder(AVFormatContext *s, const AVStream *st,
563                                enum AVCodecID codec_id);
564 
565 /**
566  * Set the time base and wrapping info for a given stream. This will be used
567  * to interpret the stream's timestamps. If the new time base is invalid
568  * (numerator or denominator are non-positive), it leaves the stream
569  * unchanged.
570  *
571  * @param st stream
572  * @param pts_wrap_bits number of bits effectively used by the pts
573  *        (used for wrap control)
574  * @param pts_num time base numerator
575  * @param pts_den time base denominator
576  */
577 void avpriv_set_pts_info(AVStream *st, int pts_wrap_bits,
578                          unsigned int pts_num, unsigned int pts_den);
579 
580 /**
581  * Set the timebase for each stream from the corresponding codec timebase and
582  * print it.
583  */
584 int ff_framehash_write_header(AVFormatContext *s);
585 
586 /**
587  * Frees a stream without modifying the corresponding AVFormatContext.
588  * Must only be called if the latter doesn't matter or if the stream
589  * is not yet attached to an AVFormatContext.
590  */
591 void ff_free_stream(AVStream **st);
592 /**
593  * Remove a stream from its AVFormatContext and free it.
594  * The stream must be the last stream of the AVFormatContext.
595  */
596 void ff_remove_stream(AVFormatContext *s, AVStream *st);
597 
598 unsigned int ff_codec_get_tag(const AVCodecTag *tags, enum AVCodecID id);
599 
600 enum AVCodecID ff_codec_get_id(const AVCodecTag *tags, unsigned int tag);
601 
602 int ff_is_intra_only(enum AVCodecID id);
603 
604 /**
605  * Select a PCM codec based on the given parameters.
606  *
607  * @param bps     bits-per-sample
608  * @param flt     floating-point
609  * @param be      big-endian
610  * @param sflags  signed flags. each bit corresponds to one byte of bit depth.
611  *                e.g. the 1st bit indicates if 8-bit should be signed or
612  *                unsigned, the 2nd bit indicates if 16-bit should be signed or
613  *                unsigned, etc... This is useful for formats such as WAVE where
614  *                only 8-bit is unsigned and all other bit depths are signed.
615  * @return        a PCM codec id or AV_CODEC_ID_NONE
616  */
617 enum AVCodecID ff_get_pcm_codec_id(int bps, int flt, int be, int sflags);
618 
619 /**
620  * Copy side data from source to destination stream
621  *
622  * @param dst pointer to destination AVStream
623  * @param src pointer to source AVStream
624  * @return >=0 on success, AVERROR code on error
625  */
626 int ff_stream_side_data_copy(AVStream *dst, const AVStream *src);
627 
628 /**
629  * Wrap ffurl_move() and log if error happens.
630  *
631  * @param url_src source path
632  * @param url_dst destination path
633  * @return        0 or AVERROR on failure
634  */
635 int ff_rename(const char *url_src, const char *url_dst, void *logctx);
636 
637 /**
638  * Allocate extradata with additional AV_INPUT_BUFFER_PADDING_SIZE at end
639  * which is always set to 0.
640  *
641  * Previously allocated extradata in par will be freed.
642  *
643  * @param size size of extradata
644  * @return 0 if OK, AVERROR_xxx on error
645  */
646 int ff_alloc_extradata(AVCodecParameters *par, int size);
647 
648 /**
649  * Copies the whilelists from one context to the other
650  */
651 int ff_copy_whiteblacklists(AVFormatContext *dst, const AVFormatContext *src);
652 
653 /*
654  * A wrapper around AVFormatContext.io_close that should be used
655  * instead of calling the pointer directly.
656  *
657  * @param s AVFormatContext
658  * @param *pb the AVIOContext to be closed and freed. Can be NULL.
659  * @return >=0 on success, negative AVERROR in case of failure
660  */
661 int ff_format_io_close(AVFormatContext *s, AVIOContext **pb);
662 
663 /* Default io_close callback, not to be used directly, use ff_format_io_close
664  * instead. */
665 void ff_format_io_close_default(AVFormatContext *s, AVIOContext *pb);
666 
667 /**
668  * Utility function to check if the file uses http or https protocol
669  *
670  * @param s AVFormatContext
671  * @param filename URL or file name to open for writing
672  */
673 int ff_is_http_proto(const char *filename);
674 
675 struct AVBPrint;
676 /**
677  * Finalize buf into extradata and set its size appropriately.
678  */
679 int ff_bprint_to_codecpar_extradata(AVCodecParameters *par, struct AVBPrint *buf);
680 
681 int ff_lock_avformat(void);
682 int ff_unlock_avformat(void);
683 
684 /**
685  * Set AVFormatContext url field to the provided pointer. The pointer must
686  * point to a valid string. The existing url field is freed if necessary. Also
687  * set the legacy filename field to the same string which was provided in url.
688  */
689 void ff_format_set_url(AVFormatContext *s, char *url);
690 
691 void avpriv_register_devices(const AVOutputFormat * const o[], const AVInputFormat * const i[]);
692 
693 #endif /* AVFORMAT_INTERNAL_H */
694