xref: /third_party/ffmpeg/libavcodec/decode.h (revision cabdff1a) 
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 */
34typedef 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 */
65int ff_decode_get_packet(AVCodecContext *avctx, AVPacket *pkt);
66
67/**
68 * Set various frame properties from the codec context / packet data.
69 */
70int 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 */
77int ff_decode_get_hw_frames_ctx(AVCodecContext *avctx,
78                                enum AVHWDeviceType dev_type);
79
80int ff_attach_decode_data(AVFrame *frame);
81
82/**
83 * Check whether the side-data of src contains a palette of
84 * size AVPALETTE_SIZE; if so, copy it to dst and return 1;
85 * else return 0.
86 * Also emit an error message upon encountering a palette
87 * with invalid size.
88 */
89int ff_copy_palette(void *dst, const AVPacket *src, void *logctx);
90
91/**
92 * Perform decoder initialization and validation.
93 * Called when opening the decoder, before the FFCodec.init() call.
94 */
95int ff_decode_preinit(AVCodecContext *avctx);
96
97#endif /* AVCODEC_DECODE_H */
98