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1 /*
2  * AVPacket public API
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 AVCODEC_PACKET_H
22 #define AVCODEC_PACKET_H
23 
24 #include <stddef.h>
25 #include <stdint.h>
26 
27 #include "libavutil/attributes.h"
28 #include "libavutil/buffer.h"
29 #include "libavutil/dict.h"
30 #include "libavutil/rational.h"
31 
32 #include "libavcodec/version.h"
33 
34 /**
35  * @defgroup lavc_packet AVPacket
36  *
37  * Types and functions for working with AVPacket.
38  * @{
39  */
40 enum AVPacketSideDataType {
41     /**
42      * An AV_PKT_DATA_PALETTE side data packet contains exactly AVPALETTE_SIZE
43      * bytes worth of palette. This side data signals that a new palette is
44      * present.
45      */
46     AV_PKT_DATA_PALETTE,
47 
48     /**
49      * The AV_PKT_DATA_NEW_EXTRADATA is used to notify the codec or the format
50      * that the extradata buffer was changed and the receiving side should
51      * act upon it appropriately. The new extradata is embedded in the side
52      * data buffer and should be immediately used for processing the current
53      * frame or packet.
54      */
55     AV_PKT_DATA_NEW_EXTRADATA,
56 
57     /**
58      * An AV_PKT_DATA_PARAM_CHANGE side data packet is laid out as follows:
59      * @code
60      * u32le param_flags
61      * if (param_flags & AV_SIDE_DATA_PARAM_CHANGE_CHANNEL_COUNT)
62      *     s32le channel_count
63      * if (param_flags & AV_SIDE_DATA_PARAM_CHANGE_CHANNEL_LAYOUT)
64      *     u64le channel_layout
65      * if (param_flags & AV_SIDE_DATA_PARAM_CHANGE_SAMPLE_RATE)
66      *     s32le sample_rate
67      * if (param_flags & AV_SIDE_DATA_PARAM_CHANGE_DIMENSIONS)
68      *     s32le width
69      *     s32le height
70      * @endcode
71      */
72     AV_PKT_DATA_PARAM_CHANGE,
73 
74     /**
75      * An AV_PKT_DATA_H263_MB_INFO side data packet contains a number of
76      * structures with info about macroblocks relevant to splitting the
77      * packet into smaller packets on macroblock edges (e.g. as for RFC 2190).
78      * That is, it does not necessarily contain info about all macroblocks,
79      * as long as the distance between macroblocks in the info is smaller
80      * than the target payload size.
81      * Each MB info structure is 12 bytes, and is laid out as follows:
82      * @code
83      * u32le bit offset from the start of the packet
84      * u8    current quantizer at the start of the macroblock
85      * u8    GOB number
86      * u16le macroblock address within the GOB
87      * u8    horizontal MV predictor
88      * u8    vertical MV predictor
89      * u8    horizontal MV predictor for block number 3
90      * u8    vertical MV predictor for block number 3
91      * @endcode
92      */
93     AV_PKT_DATA_H263_MB_INFO,
94 
95     /**
96      * This side data should be associated with an audio stream and contains
97      * ReplayGain information in form of the AVReplayGain struct.
98      */
99     AV_PKT_DATA_REPLAYGAIN,
100 
101     /**
102      * This side data contains a 3x3 transformation matrix describing an affine
103      * transformation that needs to be applied to the decoded video frames for
104      * correct presentation.
105      *
106      * See libavutil/display.h for a detailed description of the data.
107      */
108     AV_PKT_DATA_DISPLAYMATRIX,
109 
110     /**
111      * This side data should be associated with a video stream and contains
112      * Stereoscopic 3D information in form of the AVStereo3D struct.
113      */
114     AV_PKT_DATA_STEREO3D,
115 
116     /**
117      * This side data should be associated with an audio stream and corresponds
118      * to enum AVAudioServiceType.
119      */
120     AV_PKT_DATA_AUDIO_SERVICE_TYPE,
121 
122     /**
123      * This side data contains quality related information from the encoder.
124      * @code
125      * u32le quality factor of the compressed frame. Allowed range is between 1 (good) and FF_LAMBDA_MAX (bad).
126      * u8    picture type
127      * u8    error count
128      * u16   reserved
129      * u64le[error count] sum of squared differences between encoder in and output
130      * @endcode
131      */
132     AV_PKT_DATA_QUALITY_STATS,
133 
134     /**
135      * This side data contains an integer value representing the stream index
136      * of a "fallback" track.  A fallback track indicates an alternate
137      * track to use when the current track can not be decoded for some reason.
138      * e.g. no decoder available for codec.
139      */
140     AV_PKT_DATA_FALLBACK_TRACK,
141 
142     /**
143      * This side data corresponds to the AVCPBProperties struct.
144      */
145     AV_PKT_DATA_CPB_PROPERTIES,
146 
147     /**
148      * Recommmends skipping the specified number of samples
149      * @code
150      * u32le number of samples to skip from start of this packet
151      * u32le number of samples to skip from end of this packet
152      * u8    reason for start skip
153      * u8    reason for end   skip (0=padding silence, 1=convergence)
154      * @endcode
155      */
156     AV_PKT_DATA_SKIP_SAMPLES,
157 
158     /**
159      * An AV_PKT_DATA_JP_DUALMONO side data packet indicates that
160      * the packet may contain "dual mono" audio specific to Japanese DTV
161      * and if it is true, recommends only the selected channel to be used.
162      * @code
163      * u8    selected channels (0=mail/left, 1=sub/right, 2=both)
164      * @endcode
165      */
166     AV_PKT_DATA_JP_DUALMONO,
167 
168     /**
169      * A list of zero terminated key/value strings. There is no end marker for
170      * the list, so it is required to rely on the side data size to stop.
171      */
172     AV_PKT_DATA_STRINGS_METADATA,
173 
174     /**
175      * Subtitle event position
176      * @code
177      * u32le x1
178      * u32le y1
179      * u32le x2
180      * u32le y2
181      * @endcode
182      */
183     AV_PKT_DATA_SUBTITLE_POSITION,
184 
185     /**
186      * Data found in BlockAdditional element of matroska container. There is
187      * no end marker for the data, so it is required to rely on the side data
188      * size to recognize the end. 8 byte id (as found in BlockAddId) followed
189      * by data.
190      */
191     AV_PKT_DATA_MATROSKA_BLOCKADDITIONAL,
192 
193     /**
194      * The optional first identifier line of a WebVTT cue.
195      */
196     AV_PKT_DATA_WEBVTT_IDENTIFIER,
197 
198     /**
199      * The optional settings (rendering instructions) that immediately
200      * follow the timestamp specifier of a WebVTT cue.
201      */
202     AV_PKT_DATA_WEBVTT_SETTINGS,
203 
204     /**
205      * A list of zero terminated key/value strings. There is no end marker for
206      * the list, so it is required to rely on the side data size to stop. This
207      * side data includes updated metadata which appeared in the stream.
208      */
209     AV_PKT_DATA_METADATA_UPDATE,
210 
211     /**
212      * MPEGTS stream ID as uint8_t, this is required to pass the stream ID
213      * information from the demuxer to the corresponding muxer.
214      */
215     AV_PKT_DATA_MPEGTS_STREAM_ID,
216 
217     /**
218      * Mastering display metadata (based on SMPTE-2086:2014). This metadata
219      * should be associated with a video stream and contains data in the form
220      * of the AVMasteringDisplayMetadata struct.
221      */
222     AV_PKT_DATA_MASTERING_DISPLAY_METADATA,
223 
224     /**
225      * This side data should be associated with a video stream and corresponds
226      * to the AVSphericalMapping structure.
227      */
228     AV_PKT_DATA_SPHERICAL,
229 
230     /**
231      * Content light level (based on CTA-861.3). This metadata should be
232      * associated with a video stream and contains data in the form of the
233      * AVContentLightMetadata struct.
234      */
235     AV_PKT_DATA_CONTENT_LIGHT_LEVEL,
236 
237     /**
238      * ATSC A53 Part 4 Closed Captions. This metadata should be associated with
239      * a video stream. A53 CC bitstream is stored as uint8_t in AVPacketSideData.data.
240      * The number of bytes of CC data is AVPacketSideData.size.
241      */
242     AV_PKT_DATA_A53_CC,
243 
244     /**
245      * This side data is encryption initialization data.
246      * The format is not part of ABI, use av_encryption_init_info_* methods to
247      * access.
248      */
249     AV_PKT_DATA_ENCRYPTION_INIT_INFO,
250 
251     /**
252      * This side data contains encryption info for how to decrypt the packet.
253      * The format is not part of ABI, use av_encryption_info_* methods to access.
254      */
255     AV_PKT_DATA_ENCRYPTION_INFO,
256 
257     /**
258      * Active Format Description data consisting of a single byte as specified
259      * in ETSI TS 101 154 using AVActiveFormatDescription enum.
260      */
261     AV_PKT_DATA_AFD,
262 
263     /**
264      * Producer Reference Time data corresponding to the AVProducerReferenceTime struct,
265      * usually exported by some encoders (on demand through the prft flag set in the
266      * AVCodecContext export_side_data field).
267      */
268     AV_PKT_DATA_PRFT,
269 
270     /**
271      * ICC profile data consisting of an opaque octet buffer following the
272      * format described by ISO 15076-1.
273      */
274     AV_PKT_DATA_ICC_PROFILE,
275 
276     /**
277      * DOVI configuration
278      * ref:
279      * dolby-vision-bitstreams-within-the-iso-base-media-file-format-v2.1.2, section 2.2
280      * dolby-vision-bitstreams-in-mpeg-2-transport-stream-multiplex-v1.2, section 3.3
281      * Tags are stored in struct AVDOVIDecoderConfigurationRecord.
282      */
283     AV_PKT_DATA_DOVI_CONF,
284 
285     /**
286      * Timecode which conforms to SMPTE ST 12-1:2014. The data is an array of 4 uint32_t
287      * where the first uint32_t describes how many (1-3) of the other timecodes are used.
288      * The timecode format is described in the documentation of av_timecode_get_smpte_from_framenum()
289      * function in libavutil/timecode.h.
290      */
291     AV_PKT_DATA_S12M_TIMECODE,
292 
293     /**
294      * The number of side data types.
295      * This is not part of the public API/ABI in the sense that it may
296      * change when new side data types are added.
297      * This must stay the last enum value.
298      * If its value becomes huge, some code using it
299      * needs to be updated as it assumes it to be smaller than other limits.
300      */
301     AV_PKT_DATA_NB
302 };
303 
304 #define AV_PKT_DATA_QUALITY_FACTOR AV_PKT_DATA_QUALITY_STATS //DEPRECATED
305 
306 typedef struct AVPacketSideData {
307     uint8_t *data;
308 #if FF_API_BUFFER_SIZE_T
309     int      size;
310 #else
311     size_t   size;
312 #endif
313     enum AVPacketSideDataType type;
314 } AVPacketSideData;
315 
316 /**
317  * This structure stores compressed data. It is typically exported by demuxers
318  * and then passed as input to decoders, or received as output from encoders and
319  * then passed to muxers.
320  *
321  * For video, it should typically contain one compressed frame. For audio it may
322  * contain several compressed frames. Encoders are allowed to output empty
323  * packets, with no compressed data, containing only side data
324  * (e.g. to update some stream parameters at the end of encoding).
325  *
326  * The semantics of data ownership depends on the buf field.
327  * If it is set, the packet data is dynamically allocated and is
328  * valid indefinitely until a call to av_packet_unref() reduces the
329  * reference count to 0.
330  *
331  * If the buf field is not set av_packet_ref() would make a copy instead
332  * of increasing the reference count.
333  *
334  * The side data is always allocated with av_malloc(), copied by
335  * av_packet_ref() and freed by av_packet_unref().
336  *
337  * sizeof(AVPacket) being a part of the public ABI is deprecated. once
338  * av_init_packet() is removed, new packets will only be able to be allocated
339  * with av_packet_alloc(), and new fields may be added to the end of the struct
340  * with a minor bump.
341  *
342  * @see av_packet_alloc
343  * @see av_packet_ref
344  * @see av_packet_unref
345  */
346 typedef struct AVPacket {
347     /**
348      * A reference to the reference-counted buffer where the packet data is
349      * stored.
350      * May be NULL, then the packet data is not reference-counted.
351      */
352     AVBufferRef *buf;
353     /**
354      * Presentation timestamp in AVStream->time_base units; the time at which
355      * the decompressed packet will be presented to the user.
356      * Can be AV_NOPTS_VALUE if it is not stored in the file.
357      * pts MUST be larger or equal to dts as presentation cannot happen before
358      * decompression, unless one wants to view hex dumps. Some formats misuse
359      * the terms dts and pts/cts to mean something different. Such timestamps
360      * must be converted to true pts/dts before they are stored in AVPacket.
361      */
362     int64_t pts;
363     /**
364      * Decompression timestamp in AVStream->time_base units; the time at which
365      * the packet is decompressed.
366      * Can be AV_NOPTS_VALUE if it is not stored in the file.
367      */
368     int64_t dts;
369     uint8_t *data;
370     int   size;
371     int   stream_index;
372     /**
373      * A combination of AV_PKT_FLAG values
374      */
375     int   flags;
376     /**
377      * Additional packet data that can be provided by the container.
378      * Packet can contain several types of side information.
379      */
380     AVPacketSideData *side_data;
381     int side_data_elems;
382 
383     /**
384      * Duration of this packet in AVStream->time_base units, 0 if unknown.
385      * Equals next_pts - this_pts in presentation order.
386      */
387     int64_t duration;
388 
389     int64_t pos;                            ///< byte position in stream, -1 if unknown
390 
391 #if FF_API_CONVERGENCE_DURATION
392     /**
393      * @deprecated Same as the duration field, but as int64_t. This was required
394      * for Matroska subtitles, whose duration values could overflow when the
395      * duration field was still an int.
396      */
397     attribute_deprecated
398     int64_t convergence_duration;
399 #endif
400 } AVPacket;
401 
402 #if FF_API_INIT_PACKET
403 attribute_deprecated
404 typedef struct AVPacketList {
405     AVPacket pkt;
406     struct AVPacketList *next;
407 } AVPacketList;
408 #endif
409 
410 #define AV_PKT_FLAG_KEY     0x0001 ///< The packet contains a keyframe
411 #define AV_PKT_FLAG_CORRUPT 0x0002 ///< The packet content is corrupted
412 /**
413  * Flag is used to discard packets which are required to maintain valid
414  * decoder state but are not required for output and should be dropped
415  * after decoding.
416  **/
417 #define AV_PKT_FLAG_DISCARD   0x0004
418 /**
419  * The packet comes from a trusted source.
420  *
421  * Otherwise-unsafe constructs such as arbitrary pointers to data
422  * outside the packet may be followed.
423  */
424 #define AV_PKT_FLAG_TRUSTED   0x0008
425 /**
426  * Flag is used to indicate packets that contain frames that can
427  * be discarded by the decoder.  I.e. Non-reference frames.
428  */
429 #define AV_PKT_FLAG_DISPOSABLE 0x0010
430 
431 enum AVSideDataParamChangeFlags {
432     AV_SIDE_DATA_PARAM_CHANGE_CHANNEL_COUNT  = 0x0001,
433     AV_SIDE_DATA_PARAM_CHANGE_CHANNEL_LAYOUT = 0x0002,
434     AV_SIDE_DATA_PARAM_CHANGE_SAMPLE_RATE    = 0x0004,
435     AV_SIDE_DATA_PARAM_CHANGE_DIMENSIONS     = 0x0008,
436 };
437 
438 /**
439  * Allocate an AVPacket and set its fields to default values.  The resulting
440  * struct must be freed using av_packet_free().
441  *
442  * @return An AVPacket filled with default values or NULL on failure.
443  *
444  * @note this only allocates the AVPacket itself, not the data buffers. Those
445  * must be allocated through other means such as av_new_packet.
446  *
447  * @see av_new_packet
448  */
449 AVPacket *av_packet_alloc(void);
450 
451 /**
452  * Create a new packet that references the same data as src.
453  *
454  * This is a shortcut for av_packet_alloc()+av_packet_ref().
455  *
456  * @return newly created AVPacket on success, NULL on error.
457  *
458  * @see av_packet_alloc
459  * @see av_packet_ref
460  */
461 AVPacket *av_packet_clone(const AVPacket *src);
462 
463 /**
464  * Free the packet, if the packet is reference counted, it will be
465  * unreferenced first.
466  *
467  * @param pkt packet to be freed. The pointer will be set to NULL.
468  * @note passing NULL is a no-op.
469  */
470 void av_packet_free(AVPacket **pkt);
471 
472 #if FF_API_INIT_PACKET
473 /**
474  * Initialize optional fields of a packet with default values.
475  *
476  * Note, this does not touch the data and size members, which have to be
477  * initialized separately.
478  *
479  * @param pkt packet
480  *
481  * @see av_packet_alloc
482  * @see av_packet_unref
483  *
484  * @deprecated This function is deprecated. Once it's removed,
485                sizeof(AVPacket) will not be a part of the ABI anymore.
486  */
487 attribute_deprecated
488 void av_init_packet(AVPacket *pkt);
489 #endif
490 
491 /**
492  * Allocate the payload of a packet and initialize its fields with
493  * default values.
494  *
495  * @param pkt packet
496  * @param size wanted payload size
497  * @return 0 if OK, AVERROR_xxx otherwise
498  */
499 int av_new_packet(AVPacket *pkt, int size);
500 
501 /**
502  * Reduce packet size, correctly zeroing padding
503  *
504  * @param pkt packet
505  * @param size new size
506  */
507 void av_shrink_packet(AVPacket *pkt, int size);
508 
509 /**
510  * Increase packet size, correctly zeroing padding
511  *
512  * @param pkt packet
513  * @param grow_by number of bytes by which to increase the size of the packet
514  */
515 int av_grow_packet(AVPacket *pkt, int grow_by);
516 
517 /**
518  * Initialize a reference-counted packet from av_malloc()ed data.
519  *
520  * @param pkt packet to be initialized. This function will set the data, size,
521  *        and buf fields, all others are left untouched.
522  * @param data Data allocated by av_malloc() to be used as packet data. If this
523  *        function returns successfully, the data is owned by the underlying AVBuffer.
524  *        The caller may not access the data through other means.
525  * @param size size of data in bytes, without the padding. I.e. the full buffer
526  *        size is assumed to be size + AV_INPUT_BUFFER_PADDING_SIZE.
527  *
528  * @return 0 on success, a negative AVERROR on error
529  */
530 int av_packet_from_data(AVPacket *pkt, uint8_t *data, int size);
531 
532 #if FF_API_AVPACKET_OLD_API
533 /**
534  * @warning This is a hack - the packet memory allocation stuff is broken. The
535  * packet is allocated if it was not really allocated.
536  *
537  * @deprecated Use av_packet_ref or av_packet_make_refcounted
538  */
539 attribute_deprecated
540 int av_dup_packet(AVPacket *pkt);
541 /**
542  * Copy packet, including contents
543  *
544  * @return 0 on success, negative AVERROR on fail
545  *
546  * @deprecated Use av_packet_ref
547  */
548 attribute_deprecated
549 int av_copy_packet(AVPacket *dst, const AVPacket *src);
550 
551 /**
552  * Copy packet side data
553  *
554  * @return 0 on success, negative AVERROR on fail
555  *
556  * @deprecated Use av_packet_copy_props
557  */
558 attribute_deprecated
559 int av_copy_packet_side_data(AVPacket *dst, const AVPacket *src);
560 
561 /**
562  * Free a packet.
563  *
564  * @deprecated Use av_packet_unref
565  *
566  * @param pkt packet to free
567  */
568 attribute_deprecated
569 void av_free_packet(AVPacket *pkt);
570 #endif
571 /**
572  * Allocate new information of a packet.
573  *
574  * @param pkt packet
575  * @param type side information type
576  * @param size side information size
577  * @return pointer to fresh allocated data or NULL otherwise
578  */
579 uint8_t* av_packet_new_side_data(AVPacket *pkt, enum AVPacketSideDataType type,
580 #if FF_API_BUFFER_SIZE_T
581                                  int size);
582 #else
583                                  size_t size);
584 #endif
585 
586 /**
587  * Wrap an existing array as a packet side data.
588  *
589  * @param pkt packet
590  * @param type side information type
591  * @param data the side data array. It must be allocated with the av_malloc()
592  *             family of functions. The ownership of the data is transferred to
593  *             pkt.
594  * @param size side information size
595  * @return a non-negative number on success, a negative AVERROR code on
596  *         failure. On failure, the packet is unchanged and the data remains
597  *         owned by the caller.
598  */
599 int av_packet_add_side_data(AVPacket *pkt, enum AVPacketSideDataType type,
600                             uint8_t *data, size_t size);
601 
602 /**
603  * Shrink the already allocated side data buffer
604  *
605  * @param pkt packet
606  * @param type side information type
607  * @param size new side information size
608  * @return 0 on success, < 0 on failure
609  */
610 int av_packet_shrink_side_data(AVPacket *pkt, enum AVPacketSideDataType type,
611 #if FF_API_BUFFER_SIZE_T
612                                int size);
613 #else
614                                size_t size);
615 #endif
616 
617 /**
618  * Get side information from packet.
619  *
620  * @param pkt packet
621  * @param type desired side information type
622  * @param size If supplied, *size will be set to the size of the side data
623  *             or to zero if the desired side data is not present.
624  * @return pointer to data if present or NULL otherwise
625  */
626 uint8_t* av_packet_get_side_data(const AVPacket *pkt, enum AVPacketSideDataType type,
627 #if FF_API_BUFFER_SIZE_T
628                                  int *size);
629 #else
630                                  size_t *size);
631 #endif
632 
633 #if FF_API_MERGE_SD_API
634 attribute_deprecated
635 int av_packet_merge_side_data(AVPacket *pkt);
636 
637 attribute_deprecated
638 int av_packet_split_side_data(AVPacket *pkt);
639 #endif
640 
641 const char *av_packet_side_data_name(enum AVPacketSideDataType type);
642 
643 /**
644  * Pack a dictionary for use in side_data.
645  *
646  * @param dict The dictionary to pack.
647  * @param size pointer to store the size of the returned data
648  * @return pointer to data if successful, NULL otherwise
649  */
650 #if FF_API_BUFFER_SIZE_T
651 uint8_t *av_packet_pack_dictionary(AVDictionary *dict, int *size);
652 #else
653 uint8_t *av_packet_pack_dictionary(AVDictionary *dict, size_t *size);
654 #endif
655 /**
656  * Unpack a dictionary from side_data.
657  *
658  * @param data data from side_data
659  * @param size size of the data
660  * @param dict the metadata storage dictionary
661  * @return 0 on success, < 0 on failure
662  */
663 #if FF_API_BUFFER_SIZE_T
664 int av_packet_unpack_dictionary(const uint8_t *data, int size, AVDictionary **dict);
665 #else
666 int av_packet_unpack_dictionary(const uint8_t *data, size_t size,
667                                 AVDictionary **dict);
668 #endif
669 
670 /**
671  * Convenience function to free all the side data stored.
672  * All the other fields stay untouched.
673  *
674  * @param pkt packet
675  */
676 void av_packet_free_side_data(AVPacket *pkt);
677 
678 /**
679  * Setup a new reference to the data described by a given packet
680  *
681  * If src is reference-counted, setup dst as a new reference to the
682  * buffer in src. Otherwise allocate a new buffer in dst and copy the
683  * data from src into it.
684  *
685  * All the other fields are copied from src.
686  *
687  * @see av_packet_unref
688  *
689  * @param dst Destination packet. Will be completely overwritten.
690  * @param src Source packet
691  *
692  * @return 0 on success, a negative AVERROR on error. On error, dst
693  *         will be blank (as if returned by av_packet_alloc()).
694  */
695 int av_packet_ref(AVPacket *dst, const AVPacket *src);
696 
697 /**
698  * Wipe the packet.
699  *
700  * Unreference the buffer referenced by the packet and reset the
701  * remaining packet fields to their default values.
702  *
703  * @param pkt The packet to be unreferenced.
704  */
705 void av_packet_unref(AVPacket *pkt);
706 
707 /**
708  * Move every field in src to dst and reset src.
709  *
710  * @see av_packet_unref
711  *
712  * @param src Source packet, will be reset
713  * @param dst Destination packet
714  */
715 void av_packet_move_ref(AVPacket *dst, AVPacket *src);
716 
717 /**
718  * Copy only "properties" fields from src to dst.
719  *
720  * Properties for the purpose of this function are all the fields
721  * beside those related to the packet data (buf, data, size)
722  *
723  * @param dst Destination packet
724  * @param src Source packet
725  *
726  * @return 0 on success AVERROR on failure.
727  */
728 int av_packet_copy_props(AVPacket *dst, const AVPacket *src);
729 
730 /**
731  * Ensure the data described by a given packet is reference counted.
732  *
733  * @note This function does not ensure that the reference will be writable.
734  *       Use av_packet_make_writable instead for that purpose.
735  *
736  * @see av_packet_ref
737  * @see av_packet_make_writable
738  *
739  * @param pkt packet whose data should be made reference counted.
740  *
741  * @return 0 on success, a negative AVERROR on error. On failure, the
742  *         packet is unchanged.
743  */
744 int av_packet_make_refcounted(AVPacket *pkt);
745 
746 /**
747  * Create a writable reference for the data described by a given packet,
748  * avoiding data copy if possible.
749  *
750  * @param pkt Packet whose data should be made writable.
751  *
752  * @return 0 on success, a negative AVERROR on failure. On failure, the
753  *         packet is unchanged.
754  */
755 int av_packet_make_writable(AVPacket *pkt);
756 
757 /**
758  * Convert valid timing fields (timestamps / durations) in a packet from one
759  * timebase to another. Timestamps with unknown values (AV_NOPTS_VALUE) will be
760  * ignored.
761  *
762  * @param pkt packet on which the conversion will be performed
763  * @param tb_src source timebase, in which the timing fields in pkt are
764  *               expressed
765  * @param tb_dst destination timebase, to which the timing fields will be
766  *               converted
767  */
768 void av_packet_rescale_ts(AVPacket *pkt, AVRational tb_src, AVRational tb_dst);
769 
770 /**
771  * @}
772  */
773 
774 #endif // AVCODEC_PACKET_H
775