FFmpeg  4.4
codec.h
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1 /*
2  * AVCodec 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_CODEC_H
22 #define AVCODEC_CODEC_H
23 
24 #include <stdint.h>
25 
26 #include "libavutil/avutil.h"
27 #include "libavutil/hwcontext.h"
28 #include "libavutil/log.h"
29 #include "libavutil/pixfmt.h"
30 #include "libavutil/rational.h"
31 #include "libavutil/samplefmt.h"
32 
33 #include "libavcodec/codec_id.h"
34 #include "libavcodec/version.h"
35 
36 /**
37  * @addtogroup lavc_core
38  * @{
39  */
40 
41 /**
42  * Decoder can use draw_horiz_band callback.
43  */
44 #define AV_CODEC_CAP_DRAW_HORIZ_BAND (1 << 0)
45 /**
46  * Codec uses get_buffer() or get_encode_buffer() for allocating buffers and
47  * supports custom allocators.
48  * If not set, it might not use get_buffer() or get_encode_buffer() at all, or
49  * use operations that assume the buffer was allocated by
50  * avcodec_default_get_buffer2 or avcodec_default_get_encode_buffer.
51  */
52 #define AV_CODEC_CAP_DR1 (1 << 1)
53 #define AV_CODEC_CAP_TRUNCATED (1 << 3)
54 /**
55  * Encoder or decoder requires flushing with NULL input at the end in order to
56  * give the complete and correct output.
57  *
58  * NOTE: If this flag is not set, the codec is guaranteed to never be fed with
59  * with NULL data. The user can still send NULL data to the public encode
60  * or decode function, but libavcodec will not pass it along to the codec
61  * unless this flag is set.
62  *
63  * Decoders:
64  * The decoder has a non-zero delay and needs to be fed with avpkt->data=NULL,
65  * avpkt->size=0 at the end to get the delayed data until the decoder no longer
66  * returns frames.
67  *
68  * Encoders:
69  * The encoder needs to be fed with NULL data at the end of encoding until the
70  * encoder no longer returns data.
71  *
72  * NOTE: For encoders implementing the AVCodec.encode2() function, setting this
73  * flag also means that the encoder must set the pts and duration for
74  * each output packet. If this flag is not set, the pts and duration will
75  * be determined by libavcodec from the input frame.
76  */
77 #define AV_CODEC_CAP_DELAY (1 << 5)
78 /**
79  * Codec can be fed a final frame with a smaller size.
80  * This can be used to prevent truncation of the last audio samples.
81  */
82 #define AV_CODEC_CAP_SMALL_LAST_FRAME (1 << 6)
83 
84 /**
85  * Codec can output multiple frames per AVPacket
86  * Normally demuxers return one frame at a time, demuxers which do not do
87  * are connected to a parser to split what they return into proper frames.
88  * This flag is reserved to the very rare category of codecs which have a
89  * bitstream that cannot be split into frames without timeconsuming
90  * operations like full decoding. Demuxers carrying such bitstreams thus
91  * may return multiple frames in a packet. This has many disadvantages like
92  * prohibiting stream copy in many cases thus it should only be considered
93  * as a last resort.
94  */
95 #define AV_CODEC_CAP_SUBFRAMES (1 << 8)
96 /**
97  * Codec is experimental and is thus avoided in favor of non experimental
98  * encoders
99  */
100 #define AV_CODEC_CAP_EXPERIMENTAL (1 << 9)
101 /**
102  * Codec should fill in channel configuration and samplerate instead of container
103  */
104 #define AV_CODEC_CAP_CHANNEL_CONF (1 << 10)
105 /**
106  * Codec supports frame-level multithreading.
107  */
108 #define AV_CODEC_CAP_FRAME_THREADS (1 << 12)
109 /**
110  * Codec supports slice-based (or partition-based) multithreading.
111  */
112 #define AV_CODEC_CAP_SLICE_THREADS (1 << 13)
113 /**
114  * Codec supports changed parameters at any point.
115  */
116 #define AV_CODEC_CAP_PARAM_CHANGE (1 << 14)
117 /**
118  * Codec supports multithreading through a method other than slice- or
119  * frame-level multithreading. Typically this marks wrappers around
120  * multithreading-capable external libraries.
121  */
122 #define AV_CODEC_CAP_OTHER_THREADS (1 << 15)
123 #if FF_API_AUTO_THREADS
124 #define AV_CODEC_CAP_AUTO_THREADS AV_CODEC_CAP_OTHER_THREADS
125 #endif
126 /**
127  * Audio encoder supports receiving a different number of samples in each call.
128  */
129 #define AV_CODEC_CAP_VARIABLE_FRAME_SIZE (1 << 16)
130 /**
131  * Decoder is not a preferred choice for probing.
132  * This indicates that the decoder is not a good choice for probing.
133  * It could for example be an expensive to spin up hardware decoder,
134  * or it could simply not provide a lot of useful information about
135  * the stream.
136  * A decoder marked with this flag should only be used as last resort
137  * choice for probing.
138  */
139 #define AV_CODEC_CAP_AVOID_PROBING (1 << 17)
140 
141 #if FF_API_UNUSED_CODEC_CAPS
142 /**
143  * Deprecated and unused. Use AVCodecDescriptor.props instead
144  */
145 #define AV_CODEC_CAP_INTRA_ONLY 0x40000000
146 /**
147  * Deprecated and unused. Use AVCodecDescriptor.props instead
148  */
149 #define AV_CODEC_CAP_LOSSLESS 0x80000000
150 #endif
151 
152 /**
153  * Codec is backed by a hardware implementation. Typically used to
154  * identify a non-hwaccel hardware decoder. For information about hwaccels, use
155  * avcodec_get_hw_config() instead.
156  */
157 #define AV_CODEC_CAP_HARDWARE (1 << 18)
158 
159 /**
160  * Codec is potentially backed by a hardware implementation, but not
161  * necessarily. This is used instead of AV_CODEC_CAP_HARDWARE, if the
162  * implementation provides some sort of internal fallback.
163  */
164 #define AV_CODEC_CAP_HYBRID (1 << 19)
165 
166 /**
167  * This codec takes the reordered_opaque field from input AVFrames
168  * and returns it in the corresponding field in AVCodecContext after
169  * encoding.
170  */
171 #define AV_CODEC_CAP_ENCODER_REORDERED_OPAQUE (1 << 20)
172 
173 /**
174  * This encoder can be flushed using avcodec_flush_buffers(). If this flag is
175  * not set, the encoder must be closed and reopened to ensure that no frames
176  * remain pending.
177  */
178 #define AV_CODEC_CAP_ENCODER_FLUSH (1 << 21)
179 
180 /**
181  * AVProfile.
182  */
183 typedef struct AVProfile {
184  int profile;
185  const char *name; ///< short name for the profile
186 } AVProfile;
187 
188 typedef struct AVCodecDefault AVCodecDefault;
189 
190 struct AVCodecContext;
191 struct AVSubtitle;
192 struct AVPacket;
193 
194 /**
195  * AVCodec.
196  */
197 typedef struct AVCodec {
198  /**
199  * Name of the codec implementation.
200  * The name is globally unique among encoders and among decoders (but an
201  * encoder and a decoder can share the same name).
202  * This is the primary way to find a codec from the user perspective.
203  */
204  const char *name;
205  /**
206  * Descriptive name for the codec, meant to be more human readable than name.
207  * You should use the NULL_IF_CONFIG_SMALL() macro to define it.
208  */
209  const char *long_name;
210  enum AVMediaType type;
211  enum AVCodecID id;
212  /**
213  * Codec capabilities.
214  * see AV_CODEC_CAP_*
215  */
217  const AVRational *supported_framerates; ///< array of supported framerates, or NULL if any, array is terminated by {0,0}
218  const enum AVPixelFormat *pix_fmts; ///< array of supported pixel formats, or NULL if unknown, array is terminated by -1
219  const int *supported_samplerates; ///< array of supported audio samplerates, or NULL if unknown, array is terminated by 0
220  const enum AVSampleFormat *sample_fmts; ///< array of supported sample formats, or NULL if unknown, array is terminated by -1
221  const uint64_t *channel_layouts; ///< array of support channel layouts, or NULL if unknown. array is terminated by 0
222  uint8_t max_lowres; ///< maximum value for lowres supported by the decoder
223  const AVClass *priv_class; ///< AVClass for the private context
224  const AVProfile *profiles; ///< array of recognized profiles, or NULL if unknown, array is terminated by {FF_PROFILE_UNKNOWN}
225 
226  /**
227  * Group name of the codec implementation.
228  * This is a short symbolic name of the wrapper backing this codec. A
229  * wrapper uses some kind of external implementation for the codec, such
230  * as an external library, or a codec implementation provided by the OS or
231  * the hardware.
232  * If this field is NULL, this is a builtin, libavcodec native codec.
233  * If non-NULL, this will be the suffix in AVCodec.name in most cases
234  * (usually AVCodec.name will be of the form "<codec_name>_<wrapper_name>").
235  */
236  const char *wrapper_name;
237 
238  /*****************************************************************
239  * No fields below this line are part of the public API. They
240  * may not be used outside of libavcodec and can be changed and
241  * removed at will.
242  * New public fields should be added right above.
243  *****************************************************************
244  */
246 #if FF_API_NEXT
247  struct AVCodec *next;
248 #endif
249  /**
250  * @name Frame-level threading support functions
251  * @{
252  */
253  /**
254  * Copy necessary context variables from a previous thread context to the current one.
255  * If not defined, the next thread will start automatically; otherwise, the codec
256  * must call ff_thread_finish_setup().
257  *
258  * dst and src will (rarely) point to the same context, in which case memcpy should be skipped.
259  */
260  int (*update_thread_context)(struct AVCodecContext *dst, const struct AVCodecContext *src);
261  /** @} */
262 
263  /**
264  * Private codec-specific defaults.
265  */
267 
268  /**
269  * Initialize codec static data, called from av_codec_iterate().
270  *
271  * This is not intended for time consuming operations as it is
272  * run for every codec regardless of that codec being used.
273  */
274  void (*init_static_data)(struct AVCodec *codec);
275 
276  int (*init)(struct AVCodecContext *);
277  int (*encode_sub)(struct AVCodecContext *, uint8_t *buf, int buf_size,
278  const struct AVSubtitle *sub);
279  /**
280  * Encode data to an AVPacket.
281  *
282  * @param avctx codec context
283  * @param avpkt output AVPacket
284  * @param[in] frame AVFrame containing the raw data to be encoded
285  * @param[out] got_packet_ptr encoder sets to 0 or 1 to indicate that a
286  * non-empty packet was returned in avpkt.
287  * @return 0 on success, negative error code on failure
288  */
289  int (*encode2)(struct AVCodecContext *avctx, struct AVPacket *avpkt,
290  const struct AVFrame *frame, int *got_packet_ptr);
291  /**
292  * Decode picture or subtitle data.
293  *
294  * @param avctx codec context
295  * @param outdata codec type dependent output struct
296  * @param[out] got_frame_ptr decoder sets to 0 or 1 to indicate that a
297  * non-empty frame or subtitle was returned in
298  * outdata.
299  * @param[in] avpkt AVPacket containing the data to be decoded
300  * @return amount of bytes read from the packet on success, negative error
301  * code on failure
302  */
303  int (*decode)(struct AVCodecContext *avctx, void *outdata,
304  int *got_frame_ptr, struct AVPacket *avpkt);
305  int (*close)(struct AVCodecContext *);
306  /**
307  * Encode API with decoupled frame/packet dataflow. This function is called
308  * to get one output packet. It should call ff_encode_get_frame() to obtain
309  * input data.
310  */
311  int (*receive_packet)(struct AVCodecContext *avctx, struct AVPacket *avpkt);
312 
313  /**
314  * Decode API with decoupled packet/frame dataflow. This function is called
315  * to get one output frame. It should call ff_decode_get_packet() to obtain
316  * input data.
317  */
318  int (*receive_frame)(struct AVCodecContext *avctx, struct AVFrame *frame);
319  /**
320  * Flush buffers.
321  * Will be called when seeking
322  */
323  void (*flush)(struct AVCodecContext *);
324  /**
325  * Internal codec capabilities.
326  * See FF_CODEC_CAP_* in internal.h
327  */
329 
330  /**
331  * Decoding only, a comma-separated list of bitstream filters to apply to
332  * packets before decoding.
333  */
334  const char *bsfs;
335 
336  /**
337  * Array of pointers to hardware configurations supported by the codec,
338  * or NULL if no hardware supported. The array is terminated by a NULL
339  * pointer.
340  *
341  * The user can only access this field via avcodec_get_hw_config().
342  */
343  const struct AVCodecHWConfigInternal *const *hw_configs;
344 
345  /**
346  * List of supported codec_tags, terminated by FF_CODEC_TAGS_END.
347  */
348  const uint32_t *codec_tags;
349 } AVCodec;
350 
351 /**
352  * Iterate over all registered codecs.
353  *
354  * @param opaque a pointer where libavcodec will store the iteration state. Must
355  * point to NULL to start the iteration.
356  *
357  * @return the next registered codec or NULL when the iteration is
358  * finished
359  */
360 const AVCodec *av_codec_iterate(void **opaque);
361 
362 /**
363  * Find a registered decoder with a matching codec ID.
364  *
365  * @param id AVCodecID of the requested decoder
366  * @return A decoder if one was found, NULL otherwise.
367  */
369 
370 /**
371  * Find a registered decoder with the specified name.
372  *
373  * @param name name of the requested decoder
374  * @return A decoder if one was found, NULL otherwise.
375  */
377 
378 /**
379  * Find a registered encoder with a matching codec ID.
380  *
381  * @param id AVCodecID of the requested encoder
382  * @return An encoder if one was found, NULL otherwise.
383  */
385 
386 /**
387  * Find a registered encoder with the specified name.
388  *
389  * @param name name of the requested encoder
390  * @return An encoder if one was found, NULL otherwise.
391  */
393 /**
394  * @return a non-zero number if codec is an encoder, zero otherwise
395  */
396 int av_codec_is_encoder(const AVCodec *codec);
397 
398 /**
399  * @return a non-zero number if codec is a decoder, zero otherwise
400  */
401 int av_codec_is_decoder(const AVCodec *codec);
402 
403 enum {
404  /**
405  * The codec supports this format via the hw_device_ctx interface.
406  *
407  * When selecting this format, AVCodecContext.hw_device_ctx should
408  * have been set to a device of the specified type before calling
409  * avcodec_open2().
410  */
412  /**
413  * The codec supports this format via the hw_frames_ctx interface.
414  *
415  * When selecting this format for a decoder,
416  * AVCodecContext.hw_frames_ctx should be set to a suitable frames
417  * context inside the get_format() callback. The frames context
418  * must have been created on a device of the specified type.
419  *
420  * When selecting this format for an encoder,
421  * AVCodecContext.hw_frames_ctx should be set to the context which
422  * will be used for the input frames before calling avcodec_open2().
423  */
425  /**
426  * The codec supports this format by some internal method.
427  *
428  * This format can be selected without any additional configuration -
429  * no device or frames context is required.
430  */
432  /**
433  * The codec supports this format by some ad-hoc method.
434  *
435  * Additional settings and/or function calls are required. See the
436  * codec-specific documentation for details. (Methods requiring
437  * this sort of configuration are deprecated and others should be
438  * used in preference.)
439  */
441 };
442 
443 typedef struct AVCodecHWConfig {
444  /**
445  * For decoders, a hardware pixel format which that decoder may be
446  * able to decode to if suitable hardware is available.
447  *
448  * For encoders, a pixel format which the encoder may be able to
449  * accept. If set to AV_PIX_FMT_NONE, this applies to all pixel
450  * formats supported by the codec.
451  */
452  enum AVPixelFormat pix_fmt;
453  /**
454  * Bit set of AV_CODEC_HW_CONFIG_METHOD_* flags, describing the possible
455  * setup methods which can be used with this configuration.
456  */
457  int methods;
458  /**
459  * The device type associated with the configuration.
460  *
461  * Must be set for AV_CODEC_HW_CONFIG_METHOD_HW_DEVICE_CTX and
462  * AV_CODEC_HW_CONFIG_METHOD_HW_FRAMES_CTX, otherwise unused.
463  */
466 
467 /**
468  * Retrieve supported hardware configurations for a codec.
469  *
470  * Values of index from zero to some maximum return the indexed configuration
471  * descriptor; all other values return NULL. If the codec does not support
472  * any hardware configurations then it will always return NULL.
473  */
474 const AVCodecHWConfig *avcodec_get_hw_config(const AVCodec *codec, int index);
475 
476 /**
477  * @}
478  */
479 
480 #endif /* AVCODEC_CODEC_H */
Convenience header that includes libavutil's core.
static AVFrame * frame
AVCodec * avcodec_find_decoder(enum AVCodecID id)
Find a registered decoder with a matching codec ID.
struct AVCodecDefault AVCodecDefault
Definition: codec.h:188
int av_codec_is_encoder(const AVCodec *codec)
const AVCodecHWConfig * avcodec_get_hw_config(const AVCodec *codec, int index)
Retrieve supported hardware configurations for a codec.
int av_codec_is_decoder(const AVCodec *codec)
AVCodec * avcodec_find_decoder_by_name(const char *name)
Find a registered decoder with the specified name.
const AVCodec * av_codec_iterate(void **opaque)
Iterate over all registered codecs.
AVCodec * avcodec_find_encoder(enum AVCodecID id)
Find a registered encoder with a matching codec ID.
AVCodec * avcodec_find_encoder_by_name(const char *name)
Find a registered encoder with the specified name.
AVCodecID
Identify the syntax and semantics of the bitstream.
Definition: codec_id.h:46
@ AV_CODEC_HW_CONFIG_METHOD_AD_HOC
The codec supports this format by some ad-hoc method.
Definition: codec.h:440
@ AV_CODEC_HW_CONFIG_METHOD_HW_FRAMES_CTX
The codec supports this format via the hw_frames_ctx interface.
Definition: codec.h:424
@ AV_CODEC_HW_CONFIG_METHOD_HW_DEVICE_CTX
The codec supports this format via the hw_device_ctx interface.
Definition: codec.h:411
@ AV_CODEC_HW_CONFIG_METHOD_INTERNAL
The codec supports this format by some internal method.
Definition: codec.h:431
AVMediaType
Definition: avutil.h:199
AVSampleFormat
Audio sample formats.
Definition: samplefmt.h:58
AVHWDeviceType
Definition: hwcontext.h:27
Libavcodec version macros.
pixel format definitions
AVPixelFormat
Pixel format.
Definition: pixfmt.h:64
Utilties for rational number calculation.
Describe the class of an AVClass context structure.
Definition: log.h:67
main external API structure.
Definition: avcodec.h:536
enum AVHWDeviceType device_type
The device type associated with the configuration.
Definition: codec.h:464
int methods
Bit set of AV_CODEC_HW_CONFIG_METHOD_* flags, describing the possible setup methods which can be used...
Definition: codec.h:457
enum AVPixelFormat pix_fmt
For decoders, a hardware pixel format which that decoder may be able to decode to if suitable hardwar...
Definition: codec.h:452
AVCodec.
Definition: codec.h:197
enum AVCodecID id
Definition: codec.h:211
const AVCodecDefault * defaults
Private codec-specific defaults.
Definition: codec.h:266
const uint64_t * channel_layouts
array of support channel layouts, or NULL if unknown. array is terminated by 0
Definition: codec.h:221
int(* receive_packet)(struct AVCodecContext *avctx, struct AVPacket *avpkt)
Encode API with decoupled frame/packet dataflow.
Definition: codec.h:311
int caps_internal
Internal codec capabilities.
Definition: codec.h:328
int(* receive_frame)(struct AVCodecContext *avctx, struct AVFrame *frame)
Decode API with decoupled packet/frame dataflow.
Definition: codec.h:318
const char * bsfs
Decoding only, a comma-separated list of bitstream filters to apply to packets before decoding.
Definition: codec.h:334
void(* init_static_data)(struct AVCodec *codec)
Initialize codec static data, called from av_codec_iterate().
Definition: codec.h:274
const AVClass * priv_class
AVClass for the private context.
Definition: codec.h:223
int(* init)(struct AVCodecContext *)
Definition: codec.h:276
const AVRational * supported_framerates
array of supported framerates, or NULL if any, array is terminated by {0,0}
Definition: codec.h:217
const struct AVCodecHWConfigInternal *const * hw_configs
Array of pointers to hardware configurations supported by the codec, or NULL if no hardware supported...
Definition: codec.h:343
int(* update_thread_context)(struct AVCodecContext *dst, const struct AVCodecContext *src)
Copy necessary context variables from a previous thread context to the current one.
Definition: codec.h:260
int(* decode)(struct AVCodecContext *avctx, void *outdata, int *got_frame_ptr, struct AVPacket *avpkt)
Decode picture or subtitle data.
Definition: codec.h:303
int priv_data_size
Definition: codec.h:245
void(* flush)(struct AVCodecContext *)
Flush buffers.
Definition: codec.h:323
enum AVSampleFormat * sample_fmts
array of supported sample formats, or NULL if unknown, array is terminated by -1
Definition: codec.h:220
const uint32_t * codec_tags
List of supported codec_tags, terminated by FF_CODEC_TAGS_END.
Definition: codec.h:348
enum AVMediaType type
Definition: codec.h:210
enum AVPixelFormat * pix_fmts
array of supported pixel formats, or NULL if unknown, array is terminated by -1
Definition: codec.h:218
const AVProfile * profiles
array of recognized profiles, or NULL if unknown, array is terminated by {FF_PROFILE_UNKNOWN}
Definition: codec.h:224
const char * long_name
Descriptive name for the codec, meant to be more human readable than name.
Definition: codec.h:209
const char * wrapper_name
Group name of the codec implementation.
Definition: codec.h:236
const char * name
Name of the codec implementation.
Definition: codec.h:204
int(* encode2)(struct AVCodecContext *avctx, struct AVPacket *avpkt, const struct AVFrame *frame, int *got_packet_ptr)
Encode data to an AVPacket.
Definition: codec.h:289
int(* close)(struct AVCodecContext *)
Definition: codec.h:305
int(* encode_sub)(struct AVCodecContext *, uint8_t *buf, int buf_size, const struct AVSubtitle *sub)
Definition: codec.h:277
const int * supported_samplerates
array of supported audio samplerates, or NULL if unknown, array is terminated by 0
Definition: codec.h:219
int capabilities
Codec capabilities.
Definition: codec.h:216
uint8_t max_lowres
maximum value for lowres supported by the decoder
Definition: codec.h:222
This structure describes decoded (raw) audio or video data.
Definition: frame.h:318
This structure stores compressed data.
Definition: packet.h:346
AVProfile.
Definition: codec.h:183
int profile
Definition: codec.h:184
const char * name
short name for the profile
Definition: codec.h:185
Rational number (pair of numerator and denominator).
Definition: rational.h:58