/src/ffmpeg/libavcodec/decode.h

Source
/*
 * generic decoding-related code
 *
 * 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 AVCODEC_DECODE_H
#define AVCODEC_DECODE_H

#include "libavutil/frame.h"
#include "libavutil/hwcontext.h"

#include "avcodec.h"

/**
 * This struct stores per-frame lavc-internal data and is attached to it via
 * private_ref.
 */
typedef struct FrameDecodeData {
    /**
     * The callback to perform some delayed processing on the frame right
     * before it is returned to the caller.
     *
     * @note This code is called at some unspecified point after the frame is
     * returned from the decoder's decode/receive_frame call. Therefore it cannot rely
     * on AVCodecContext being in any specific state, so it does not get to
     * access AVCodecContext directly at all. All the state it needs must be
     * stored in the post_process_opaque object.
     */
    int (*post_process)(void *logctx, AVFrame *frame);
    void *post_process_opaque;                        ///< RefStruct reference

    /**
     * Per-frame private data for hwaccels.
     *
     * Same as @ref post_process, but used only by some hwaccels to retrieve or
     * finalize frames, and executed first.
     */
    int (*hwaccel_priv_post_process)(void *logctx, AVFrame *frame);
    void *hwaccel_priv;
    void (*hwaccel_priv_free)(void *priv);
} FrameDecodeData;

/**
 * Called by decoders to get the next packet for decoding.
 *
 * @param pkt An empty packet to be filled with data.
 * @return 0 if a new reference has been successfully written to pkt
 *         AVERROR(EAGAIN) if no data is currently available
 *         AVERROR_EOF if and end of stream has been reached, so no more data
 *                     will be available
 */
int ff_decode_get_packet(AVCodecContext *avctx, AVPacket *pkt);

/**
 * Set various frame properties from the provided packet.
 */
int ff_decode_frame_props_from_pkt(const AVCodecContext *avctx,
                                   AVFrame *frame, const AVPacket *pkt);

/**
 * Set various frame properties from the codec context / packet data.
 */
int ff_decode_frame_props(AVCodecContext *avctx, AVFrame *frame);

static inline int ff_decode_skip_all_pixels(const AVCodecContext *avctx)
{
    return avctx->skip_pred >= AVDISCARD_ALL &&
           avctx->skip_idct >= AVDISCARD_ALL &&
           !avctx->err_recognition &&
           !(avctx->flags2 & AV_CODEC_FLAG2_CHUNKS) &&
           !(avctx->export_side_data & (AV_CODEC_EXPORT_DATA_MVS |
                                        AV_CODEC_EXPORT_DATA_VIDEO_ENC_PARAMS)) &&
           !(avctx->debug & (FF_DEBUG_QP | FF_DEBUG_MB_TYPE));
}

/**
 * Make sure avctx.hw_frames_ctx is set. If it's not set, the function will
 * try to allocate it from hw_device_ctx. If that is not possible, an error
 * message is printed, and an error code is returned.
 */
int ff_decode_get_hw_frames_ctx(AVCodecContext *avctx,
                                enum AVHWDeviceType dev_type);

int ff_attach_decode_data(AVCodecContext *avctx, AVFrame *frame);

/**
 * Check whether the side-data of src contains a palette of
 * size AVPALETTE_SIZE; if so, copy it to dst and return 1;
 * else return 0.
 * Also emit an error message upon encountering a palette
 * with invalid size.
 */
int ff_copy_palette(void *dst, const AVPacket *src, void *logctx);

/*
 * Validate and set video frame dimensions on AVCodecContext.
 *
 * Dimensions accepted here satisfy FFmpeg's generic image-size validation
 * (see av_image_check_size2()). Decoder code normally should not duplicate
 * generic width/height overflow checks before ff_get_buffer(); add local
 * checks only for codec-specific derived sizes or complexity bounds.
 */
int ff_set_dimensions(AVCodecContext *s, int width, int height);

/**
 * Check that the provided sample aspect ratio is valid and set it on the codec
 * context.
 */
int ff_set_sar(AVCodecContext *avctx, AVRational sar);

/**
 * Select the (possibly hardware accelerated) pixel format.
 * This is a wrapper around AVCodecContext.get_format() and should be used
 * instead of calling get_format() directly.
 *
 * The list of pixel formats must contain at least one valid entry, and is
 * terminated with AV_PIX_FMT_NONE. If it is possible to decode to software,
 * the first entry after the last hwaccel one in the list must be the most
 * accurate software format, followed by less accurate ones in order of
 * preference.
 * If it is not possible to decode to software, AVCodecContext.sw_pix_fmt
 * must be set before calling this function.
 */
int ff_get_format(AVCodecContext *avctx, const enum AVPixelFormat *fmt);

/**
 * Get a buffer for a frame. This is a wrapper around
 * AVCodecContext.get_buffer() and should be used instead calling get_buffer()
 * directly.
 */
int ff_get_buffer(AVCodecContext *avctx, AVFrame *frame, int flags);

#define FF_REGET_BUFFER_FLAG_READONLY 1 ///< the returned buffer does not need to be writable
/**
 * Identical in function to ff_get_buffer(), except it reuses the existing buffer
 * if available.
 */
int ff_reget_buffer(AVCodecContext *avctx, AVFrame *frame, int flags);

/**
 * Add or update AV_FRAME_DATA_MATRIXENCODING side data.
 */
int ff_side_data_update_matrix_encoding(AVFrame *frame,
                                        enum AVMatrixEncoding matrix_encoding);

/**
 * Allocate a hwaccel frame private data if the provided avctx
 * uses a hwaccel method that needs it. The returned data is
 * a RefStruct reference (if allocated).
 *
 * @param  avctx                   The codec context
 * @param  hwaccel_picture_private Pointer to return hwaccel_picture_private
 * @return 0 on success, < 0 on error
 */
int ff_hwaccel_frame_priv_alloc(AVCodecContext *avctx, void **hwaccel_picture_private);

/**
 * Get side data of the given type from a decoding context.
 */
const AVPacketSideData *ff_get_coded_side_data(const AVCodecContext *avctx,
                                               enum AVPacketSideDataType type);

/**
 * Wrapper around av_frame_new_side_data, which rejects side data overridden by
 * the demuxer. Returns 0 on success, and a negative error code otherwise.
 * If successful and sd is not NULL, *sd may either contain a pointer to the new
 * side data, or NULL in case the side data was already present.
 */
int ff_frame_new_side_data(const AVCodecContext *avctx, AVFrame *frame,
                           enum AVFrameSideDataType type, size_t size,
                           AVFrameSideData **sd);

/**
 * Similar to `ff_frame_new_side_data`, but using an existing buffer ref.
 *
 * *buf is ALWAYS consumed by this function and NULL written in its place, even
 * on failure.
 */
int ff_frame_new_side_data_from_buf(const AVCodecContext *avctx,
                                    AVFrame *frame, enum AVFrameSideDataType type,
                                    AVBufferRef **buf);

/**
 * Same as `ff_frame_new_side_data_from_buf`, but taking a AVFrameSideData
 * array directly instead of an AVFrame.
 */
int ff_frame_new_side_data_from_buf_ext(const AVCodecContext *avctx,
                                        AVFrameSideData ***sd, int *nb_sd,
                                        enum AVFrameSideDataType type,
                                        AVBufferRef **buf);

struct AVMasteringDisplayMetadata;
struct AVContentLightMetadata;

/**
 * Wrapper around av_mastering_display_metadata_create_side_data(), which
 * rejects side data overridden by the demuxer. Returns 0 on success, and a
 * negative error code otherwise. If successful, *mdm may either be a pointer to
 * the new side data, or NULL in case the side data was already present.
 */
int ff_decode_mastering_display_new(const AVCodecContext *avctx, AVFrame *frame,
                                    struct AVMasteringDisplayMetadata **mdm);

/**
 * Same as `ff_decode_mastering_display_new`, but taking a AVFrameSideData
 * array directly instead of an AVFrame.
 */
int ff_decode_mastering_display_new_ext(const AVCodecContext *avctx,
                                        AVFrameSideData ***sd, int *nb_sd,
                                        struct AVMasteringDisplayMetadata **mdm);

/**
 * Wrapper around av_content_light_metadata_create_side_data(), which
 * rejects side data overridden by the demuxer. Returns 0 on success, and a
 * negative error code otherwise. If successful, *clm may either be a pointer to
 * the new side data, or NULL in case the side data was already present.
 */
int ff_decode_content_light_new(const AVCodecContext *avctx, AVFrame *frame,
                                struct AVContentLightMetadata **clm);

/**
 * Same as `ff_decode_content_light_new`, but taking a AVFrameSideData
 * array directly instead of an AVFrame.
 */
int ff_decode_content_light_new_ext(const AVCodecContext *avctx,
                                    AVFrameSideData ***sd, int *nb_sd,
                                    struct AVContentLightMetadata **clm);

/**
 * Get the data of a subtitle packet followed by a 0 byte.
 *
 * @return avpkt->data if avpkt->size <= 0 or its first padding byte is 0,
 *         otherwise a copy valid until the decode callback returns,
 *         NULL on allocation failure
 */
const char *ff_decode_subtitle_text(AVCodecContext *avctx, const AVPacket *avpkt);

#endif /* AVCODEC_DECODE_H */

Coverage Report

Created: 2026-10-28 07:09

Line	Count	Source
1		/*
2		* generic decoding-related code
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_DECODE_H
22		#define AVCODEC_DECODE_H
23
24		#include "libavutil/frame.h"
25		#include "libavutil/hwcontext.h"
26
27		#include "avcodec.h"
28
29		/**
30		* This struct stores per-frame lavc-internal data and is attached to it via
31		* private_ref.
32		*/
33		typedef struct FrameDecodeData {
34		/**
35		* The callback to perform some delayed processing on the frame right
36		* before it is returned to the caller.
37		*
38		* @note This code is called at some unspecified point after the frame is
39		* returned from the decoder's decode/receive_frame call. Therefore it cannot rely
40		* on AVCodecContext being in any specific state, so it does not get to
41		* access AVCodecContext directly at all. All the state it needs must be
42		* stored in the post_process_opaque object.
43		*/
44		int (post_process)(void logctx, AVFrame *frame);
45		void *post_process_opaque; ///< RefStruct reference
46
47		/**
48		* Per-frame private data for hwaccels.
49		*
50		* Same as @ref post_process, but used only by some hwaccels to retrieve or
51		* finalize frames, and executed first.
52		*/
53		int (hwaccel_priv_post_process)(void logctx, AVFrame *frame);
54		void *hwaccel_priv;
55		void (hwaccel_priv_free)(void priv);
56		} FrameDecodeData;
57
58		/**
59		* Called by decoders to get the next packet for decoding.
60		*
61		* @param pkt An empty packet to be filled with data.
62		* @return 0 if a new reference has been successfully written to pkt
63		* AVERROR(EAGAIN) if no data is currently available
64		* AVERROR_EOF if and end of stream has been reached, so no more data
65		* will be available
66		*/
67		int ff_decode_get_packet(AVCodecContext avctx, AVPacket pkt);
68
69		/**
70		* Set various frame properties from the provided packet.
71		*/
72		int ff_decode_frame_props_from_pkt(const AVCodecContext *avctx,
73		AVFrame frame, const AVPacket pkt);
74
75		/**
76		* Set various frame properties from the codec context / packet data.
77		*/
78		int ff_decode_frame_props(AVCodecContext avctx, AVFrame frame);
79
80		static inline int ff_decode_skip_all_pixels(const AVCodecContext *avctx)
81	0	{
82	0	return avctx->skip_pred >= AVDISCARD_ALL &&
83	0	avctx->skip_idct >= AVDISCARD_ALL &&
84	0	!avctx->err_recognition &&
85	0	!(avctx->flags2 & AV_CODEC_FLAG2_CHUNKS) &&
86	0	!(avctx->export_side_data & (AV_CODEC_EXPORT_DATA_MVS \|
87	0	AV_CODEC_EXPORT_DATA_VIDEO_ENC_PARAMS)) &&
88	0	!(avctx->debug & (FF_DEBUG_QP \| FF_DEBUG_MB_TYPE));
89	0	} Unexecuted instantiation: avcodec.c:ff_decode_skip_all_pixels Unexecuted instantiation: decode.c:ff_decode_skip_all_pixels Unexecuted instantiation: pthread_frame.c:ff_decode_skip_all_pixels Unexecuted instantiation: utils.c:ff_decode_skip_all_pixels
90
91		/**
92		* Make sure avctx.hw_frames_ctx is set. If it's not set, the function will
93		* try to allocate it from hw_device_ctx. If that is not possible, an error
94		* message is printed, and an error code is returned.
95		*/
96		int ff_decode_get_hw_frames_ctx(AVCodecContext *avctx,
97		enum AVHWDeviceType dev_type);
98
99		int ff_attach_decode_data(AVCodecContext avctx, AVFrame frame);
100
101		/**
102		* Check whether the side-data of src contains a palette of
103		* size AVPALETTE_SIZE; if so, copy it to dst and return 1;
104		* else return 0.
105		* Also emit an error message upon encountering a palette
106		* with invalid size.
107		*/
108		int ff_copy_palette(void dst, const AVPacket src, void *logctx);
109
110		/*
111		* Validate and set video frame dimensions on AVCodecContext.
112		*
113		* Dimensions accepted here satisfy FFmpeg's generic image-size validation
114		* (see av_image_check_size2()). Decoder code normally should not duplicate
115		* generic width/height overflow checks before ff_get_buffer(); add local
116		* checks only for codec-specific derived sizes or complexity bounds.
117		*/
118		int ff_set_dimensions(AVCodecContext *s, int width, int height);
119
120		/**
121		* Check that the provided sample aspect ratio is valid and set it on the codec
122		* context.
123		*/
124		int ff_set_sar(AVCodecContext *avctx, AVRational sar);
125
126		/**
127		* Select the (possibly hardware accelerated) pixel format.
128		* This is a wrapper around AVCodecContext.get_format() and should be used
129		* instead of calling get_format() directly.
130		*
131		* The list of pixel formats must contain at least one valid entry, and is
132		* terminated with AV_PIX_FMT_NONE. If it is possible to decode to software,
133		* the first entry after the last hwaccel one in the list must be the most
134		* accurate software format, followed by less accurate ones in order of
135		* preference.
136		* If it is not possible to decode to software, AVCodecContext.sw_pix_fmt
137		* must be set before calling this function.
138		*/
139		int ff_get_format(AVCodecContext avctx, const enum AVPixelFormat fmt);
140
141		/**
142		* Get a buffer for a frame. This is a wrapper around
143		* AVCodecContext.get_buffer() and should be used instead calling get_buffer()
144		* directly.
145		*/
146		int ff_get_buffer(AVCodecContext avctx, AVFrame frame, int flags);
147
148	0	#define FF_REGET_BUFFER_FLAG_READONLY 1 ///< the returned buffer does not need to be writable
149		/**
150		* Identical in function to ff_get_buffer(), except it reuses the existing buffer
151		* if available.
152		*/
153		int ff_reget_buffer(AVCodecContext avctx, AVFrame frame, int flags);
154
155		/**
156		* Add or update AV_FRAME_DATA_MATRIXENCODING side data.
157		*/
158		int ff_side_data_update_matrix_encoding(AVFrame *frame,
159		enum AVMatrixEncoding matrix_encoding);
160
161		/**
162		* Allocate a hwaccel frame private data if the provided avctx
163		* uses a hwaccel method that needs it. The returned data is
164		* a RefStruct reference (if allocated).
165		*
166		* @param avctx The codec context
167		* @param hwaccel_picture_private Pointer to return hwaccel_picture_private
168		* @return 0 on success, < 0 on error
169		*/
170		int ff_hwaccel_frame_priv_alloc(AVCodecContext avctx, void *hwaccel_picture_private);
171
172		/**
173		* Get side data of the given type from a decoding context.
174		*/
175		const AVPacketSideData ff_get_coded_side_data(const AVCodecContext avctx,
176		enum AVPacketSideDataType type);
177
178		/**
179		* Wrapper around av_frame_new_side_data, which rejects side data overridden by
180		* the demuxer. Returns 0 on success, and a negative error code otherwise.
181		* If successful and sd is not NULL, *sd may either contain a pointer to the new
182		* side data, or NULL in case the side data was already present.
183		*/
184		int ff_frame_new_side_data(const AVCodecContext avctx, AVFrame frame,
185		enum AVFrameSideDataType type, size_t size,
186		AVFrameSideData **sd);
187
188		/**
189		* Similar to `ff_frame_new_side_data`, but using an existing buffer ref.
190		*
191		* *buf is ALWAYS consumed by this function and NULL written in its place, even
192		* on failure.
193		*/
194		int ff_frame_new_side_data_from_buf(const AVCodecContext *avctx,
195		AVFrame *frame, enum AVFrameSideDataType type,
196		AVBufferRef **buf);
197
198		/**
199		* Same as `ff_frame_new_side_data_from_buf`, but taking a AVFrameSideData
200		* array directly instead of an AVFrame.
201		*/
202		int ff_frame_new_side_data_from_buf_ext(const AVCodecContext *avctx,
203		AVFrameSideData **sd, int nb_sd,
204		enum AVFrameSideDataType type,
205		AVBufferRef **buf);
206
207		struct AVMasteringDisplayMetadata;
208		struct AVContentLightMetadata;
209
210		/**
211		* Wrapper around av_mastering_display_metadata_create_side_data(), which
212		* rejects side data overridden by the demuxer. Returns 0 on success, and a
213		* negative error code otherwise. If successful, *mdm may either be a pointer to
214		* the new side data, or NULL in case the side data was already present.
215		*/
216		int ff_decode_mastering_display_new(const AVCodecContext avctx, AVFrame frame,
217		struct AVMasteringDisplayMetadata **mdm);
218
219		/**
220		* Same as `ff_decode_mastering_display_new`, but taking a AVFrameSideData
221		* array directly instead of an AVFrame.
222		*/
223		int ff_decode_mastering_display_new_ext(const AVCodecContext *avctx,
224		AVFrameSideData **sd, int nb_sd,
225		struct AVMasteringDisplayMetadata **mdm);
226
227		/**
228		* Wrapper around av_content_light_metadata_create_side_data(), which
229		* rejects side data overridden by the demuxer. Returns 0 on success, and a
230		* negative error code otherwise. If successful, *clm may either be a pointer to
231		* the new side data, or NULL in case the side data was already present.
232		*/
233		int ff_decode_content_light_new(const AVCodecContext avctx, AVFrame frame,
234		struct AVContentLightMetadata **clm);
235
236		/**
237		* Same as `ff_decode_content_light_new`, but taking a AVFrameSideData
238		* array directly instead of an AVFrame.
239		*/
240		int ff_decode_content_light_new_ext(const AVCodecContext *avctx,
241		AVFrameSideData **sd, int nb_sd,
242		struct AVContentLightMetadata **clm);
243
244		/**
245		* Get the data of a subtitle packet followed by a 0 byte.
246		*
247		* @return avpkt->data if avpkt->size <= 0 or its first padding byte is 0,
248		* otherwise a copy valid until the decode callback returns,
249		* NULL on allocation failure
250		*/
251		const char ff_decode_subtitle_text(AVCodecContext avctx, const AVPacket *avpkt);
252
253		#endif /* AVCODEC_DECODE_H */