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| Rev | Author | Line No. | Line |
|---|---|---|---|
| 4349 | Serge | 1 | /* |
| 2 | * Generic buffer queue |
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| 3 | * Copyright (c) 2012 Nicolas George |
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| 4 | * |
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| 5 | * This file is part of FFmpeg. |
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| 6 | * |
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| 7 | * FFmpeg is free software; you can redistribute it and/or |
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| 8 | * modify it under the terms of the GNU Lesser General Public |
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| 9 | * License as published by the Free Software Foundation; either |
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| 10 | * version 2.1 of the License, or (at your option) any later version. |
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| 11 | * |
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| 12 | * FFmpeg is distributed in the hope that it will be useful, |
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| 13 | * but WITHOUT ANY WARRANTY; without even the implied warranty of |
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| 14 | * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU |
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| 15 | * Lesser General Public License for more details. |
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| 16 | * |
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| 17 | * You should have received a copy of the GNU Lesser General Public |
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| 18 | * License along with FFmpeg; if not, write to the Free Software |
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| 19 | * Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA |
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| 20 | */ |
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| 21 | |||
| 22 | #ifndef AVFILTER_BUFFERQUEUE_H |
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| 23 | #define AVFILTER_BUFFERQUEUE_H |
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| 24 | |||
| 25 | /** |
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| 26 | * FFBufQueue: simple AVFrame queue API |
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| 27 | * |
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| 28 | * Note: this API is not thread-safe. Concurrent access to the same queue |
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| 29 | * must be protected by a mutex or any synchronization mechanism. |
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| 30 | */ |
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| 31 | |||
| 32 | /** |
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| 33 | * Maximum size of the queue. |
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| 34 | * |
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| 35 | * This value can be overridden by definying it before including this |
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| 36 | * header. |
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| 37 | * Powers of 2 are recommended. |
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| 38 | */ |
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| 39 | #ifndef FF_BUFQUEUE_SIZE |
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| 40 | #define FF_BUFQUEUE_SIZE 32 |
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| 41 | #endif |
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| 42 | |||
| 43 | #include "avfilter.h" |
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| 44 | #include "libavutil/avassert.h" |
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| 45 | |||
| 46 | /** |
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| 47 | * Structure holding the queue |
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| 48 | */ |
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| 49 | struct FFBufQueue { |
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| 50 | AVFrame *queue[FF_BUFQUEUE_SIZE]; |
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| 51 | unsigned short head; |
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| 52 | unsigned short available; /**< number of available buffers */ |
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| 53 | }; |
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| 54 | |||
| 55 | #define BUCKET(i) queue->queue[(queue->head + (i)) % FF_BUFQUEUE_SIZE] |
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| 56 | |||
| 57 | /** |
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| 58 | * Test if a buffer queue is full. |
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| 59 | */ |
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| 60 | static inline int ff_bufqueue_is_full(struct FFBufQueue *queue) |
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| 61 | { |
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| 62 | return queue->available == FF_BUFQUEUE_SIZE; |
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| 63 | } |
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| 64 | |||
| 65 | /** |
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| 66 | * Add a buffer to the queue. |
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| 67 | * |
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| 68 | * If the queue is already full, then the current last buffer is dropped |
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| 69 | * (and unrefed) with a warning before adding the new buffer. |
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| 70 | */ |
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| 71 | static inline void ff_bufqueue_add(void *log, struct FFBufQueue *queue, |
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| 72 | AVFrame *buf) |
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| 73 | { |
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| 74 | if (ff_bufqueue_is_full(queue)) { |
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| 75 | av_log(log, AV_LOG_WARNING, "Buffer queue overflow, dropping.\n"); |
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| 76 | av_frame_free(&BUCKET(--queue->available)); |
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| 77 | } |
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| 78 | BUCKET(queue->available++) = buf; |
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| 79 | } |
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| 80 | |||
| 81 | /** |
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| 82 | * Get a buffer from the queue without altering it. |
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| 83 | * |
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| 84 | * Buffer with index 0 is the first buffer in the queue. |
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| 85 | * Return NULL if the queue has not enough buffers. |
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| 86 | */ |
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| 87 | static inline AVFrame *ff_bufqueue_peek(struct FFBufQueue *queue, |
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| 88 | unsigned index) |
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| 89 | { |
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| 90 | return index < queue->available ? BUCKET(index) : NULL; |
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| 91 | } |
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| 92 | |||
| 93 | /** |
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| 94 | * Get the first buffer from the queue and remove it. |
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| 95 | * |
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| 96 | * Do not use on an empty queue. |
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| 97 | */ |
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| 98 | static inline AVFrame *ff_bufqueue_get(struct FFBufQueue *queue) |
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| 99 | { |
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| 100 | AVFrame *ret = queue->queue[queue->head]; |
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| 101 | av_assert0(queue->available); |
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| 102 | queue->available--; |
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| 103 | queue->queue[queue->head] = NULL; |
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| 104 | queue->head = (queue->head + 1) % FF_BUFQUEUE_SIZE; |
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| 105 | return ret; |
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| 106 | } |
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| 107 | |||
| 108 | /** |
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| 109 | * Unref and remove all buffers from the queue. |
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| 110 | */ |
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| 111 | static inline void ff_bufqueue_discard_all(struct FFBufQueue *queue) |
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| 112 | { |
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| 113 | while (queue->available) { |
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| 114 | AVFrame *buf = ff_bufqueue_get(queue); |
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| 115 | av_frame_free(&buf); |
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| 116 | } |
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| 117 | } |
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| 118 | |||
| 119 | #undef BUCKET |
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| 120 | |||
| 121 | #endif /* AVFILTER_BUFFERQUEUE_H */ |