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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/buffer.h"
25 #include "libavutil/frame.h"
26 #include "libavutil/hwcontext.h"
27 
28 #include "avcodec.h"
29 
30 /**
31  * This struct stores per-frame lavc-internal data and is attached to it via
32  * private_ref.
33  */
34 typedef struct FrameDecodeData {
35     /**
36      * The callback to perform some delayed processing on the frame right
37      * before it is returned to the caller.
38      *
39      * @note This code is called at some unspecified point after the frame is
40      * returned from the decoder's decode/receive_frame call. Therefore it cannot rely
41      * on AVCodecContext being in any specific state, so it does not get to
42      * access AVCodecContext directly at all. All the state it needs must be
43      * stored in the post_process_opaque object.
44      */
45     int (*post_process)(void *logctx, AVFrame *frame);
46     void *post_process_opaque;
47     void (*post_process_opaque_free)(void *opaque);
48 
49     /**
50      * Per-frame private data for hwaccels.
51      */
52     void *hwaccel_priv;
53     void (*hwaccel_priv_free)(void *priv);
54 } FrameDecodeData;
55 
56 /**
57  * Called by decoders to get the next packet for decoding.
58  *
59  * @param pkt An empty packet to be filled with data.
60  * @return 0 if a new reference has been successfully written to pkt
61  *         AVERROR(EAGAIN) if no data is currently available
62  *         AVERROR_EOF if and end of stream has been reached, so no more data
63  *                     will be available
64  */
65 int ff_decode_get_packet(AVCodecContext *avctx, AVPacket *pkt);
66 
67 /**
68  * Set various frame properties from the codec context / packet data.
69  */
70 int ff_decode_frame_props(AVCodecContext *avctx, AVFrame *frame);
71 
72 /**
73  * Make sure avctx.hw_frames_ctx is set. If it's not set, the function will
74  * try to allocate it from hw_device_ctx. If that is not possible, an error
75  * message is printed, and an error code is returned.
76  */
77 int ff_decode_get_hw_frames_ctx(AVCodecContext *avctx,
78                                 enum AVHWDeviceType dev_type);
79 
80 int ff_attach_decode_data(AVFrame *frame);
81 
82 /**
83  * Perform decoder initialization and validation.
84  * Called when opening the decoder, before the AVCodec.init() call.
85  */
86 int ff_decode_preinit(AVCodecContext *avctx);
87 
88 #endif /* AVCODEC_DECODE_H */
89