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fifo.c
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1 /*
2  * Copyright (c) 2007 Bobby Bingham
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 /**
22  * @file
23  * FIFO buffering filter
24  */
25 
26 #include "libavutil/avassert.h"
28 #include "libavutil/common.h"
29 #include "libavutil/mathematics.h"
30 #include "libavutil/samplefmt.h"
31 
32 #include "audio.h"
33 #include "avfilter.h"
34 #include "internal.h"
35 #include "video.h"
36 
37 typedef struct Buf {
39  struct Buf *next;
40 } Buf;
41 
42 typedef struct {
44  Buf *last; ///< last buffered frame
45 
46  /**
47  * When a specific number of output samples is requested, the partial
48  * buffer is stored here
49  */
51  int allocated_samples; ///< number of samples out was allocated for
52 } FifoContext;
53 
54 static av_cold int init(AVFilterContext *ctx)
55 {
56  FifoContext *fifo = ctx->priv;
57  fifo->last = &fifo->root;
58 
59  return 0;
60 }
61 
62 static av_cold void uninit(AVFilterContext *ctx)
63 {
64  FifoContext *fifo = ctx->priv;
65  Buf *buf, *tmp;
66 
67  for (buf = fifo->root.next; buf; buf = tmp) {
68  tmp = buf->next;
69  av_frame_free(&buf->frame);
70  av_free(buf);
71  }
72 
73  av_frame_free(&fifo->out);
74 }
75 
76 static int add_to_queue(AVFilterLink *inlink, AVFrame *frame)
77 {
78  FifoContext *fifo = inlink->dst->priv;
79 
80  fifo->last->next = av_mallocz(sizeof(Buf));
81  if (!fifo->last->next) {
82  av_frame_free(&frame);
83  return AVERROR(ENOMEM);
84  }
85 
86  fifo->last = fifo->last->next;
87  fifo->last->frame = frame;
88 
89  return 0;
90 }
91 
92 static void queue_pop(FifoContext *s)
93 {
94  Buf *tmp = s->root.next->next;
95  if (s->last == s->root.next)
96  s->last = &s->root;
97  av_freep(&s->root.next);
98  s->root.next = tmp;
99 }
100 
101 /**
102  * Move data pointers and pts offset samples forward.
103  */
105  int offset)
106 {
108  int planar = av_sample_fmt_is_planar(link->format);
109  int planes = planar ? nb_channels : 1;
110  int block_align = av_get_bytes_per_sample(link->format) * (planar ? 1 : nb_channels);
111  int i;
112 
113  av_assert0(frame->nb_samples > offset);
114 
115  for (i = 0; i < planes; i++)
116  frame->extended_data[i] += block_align * offset;
117  if (frame->data != frame->extended_data)
118  memcpy(frame->data, frame->extended_data,
119  FFMIN(planes, FF_ARRAY_ELEMS(frame->data)) * sizeof(*frame->data));
120  frame->linesize[0] -= block_align*offset;
121  frame->nb_samples -= offset;
122 
123  if (frame->pts != AV_NOPTS_VALUE) {
124  frame->pts += av_rescale_q(offset, (AVRational){1, link->sample_rate},
125  link->time_base);
126  }
127 }
128 
130 {
131  int planes = av_sample_fmt_is_planar(frame->format) ?
133  int min_align = 128;
134  int p;
135 
136  for (p = 0; p < planes; p++) {
137  int cur_align = 128;
138  while ((intptr_t)frame->extended_data[p] % cur_align)
139  cur_align >>= 1;
140  if (cur_align < min_align)
141  min_align = cur_align;
142  }
143  return min_align;
144 }
145 
147 {
148  AVFilterLink *link = ctx->outputs[0];
149  FifoContext *s = ctx->priv;
150  AVFrame *head = s->root.next ? s->root.next->frame : NULL;
151  AVFrame *out;
152  int ret;
153 
154  /* if head is NULL then we're flushing the remaining samples in out */
155  if (!head && !s->out)
156  return AVERROR_EOF;
157 
158  if (!s->out &&
159  head->nb_samples >= link->request_samples &&
160  calc_ptr_alignment(head) >= 32) {
161  if (head->nb_samples == link->request_samples) {
162  out = head;
163  queue_pop(s);
164  } else {
165  out = av_frame_clone(head);
166  if (!out)
167  return AVERROR(ENOMEM);
168 
169  out->nb_samples = link->request_samples;
170  buffer_offset(link, head, link->request_samples);
171  }
172  } else {
174 
175  if (!s->out) {
176  s->out = ff_get_audio_buffer(link, link->request_samples);
177  if (!s->out)
178  return AVERROR(ENOMEM);
179 
180  s->out->nb_samples = 0;
181  s->out->pts = head->pts;
183  } else if (link->request_samples != s->allocated_samples) {
184  av_log(ctx, AV_LOG_ERROR, "request_samples changed before the "
185  "buffer was returned.\n");
186  return AVERROR(EINVAL);
187  }
188 
189  while (s->out->nb_samples < s->allocated_samples) {
190  int len;
191 
192  if (!s->root.next) {
193  ret = ff_request_frame(ctx->inputs[0]);
194  if (ret == AVERROR_EOF) {
196  s->out->nb_samples,
197  s->allocated_samples -
198  s->out->nb_samples,
199  nb_channels, link->format);
201  break;
202  } else if (ret < 0)
203  return ret;
204  av_assert0(s->root.next); // If ff_request_frame() succeeded then we should have a frame
205  }
206  head = s->root.next->frame;
207 
208  len = FFMIN(s->allocated_samples - s->out->nb_samples,
209  head->nb_samples);
210 
212  s->out->nb_samples, 0, len, nb_channels,
213  link->format);
214  s->out->nb_samples += len;
215 
216  if (len == head->nb_samples) {
217  av_frame_free(&head);
218  queue_pop(s);
219  } else {
220  buffer_offset(link, head, len);
221  }
222  }
223  out = s->out;
224  s->out = NULL;
225  }
226  return ff_filter_frame(link, out);
227 }
228 
229 static int request_frame(AVFilterLink *outlink)
230 {
231  FifoContext *fifo = outlink->src->priv;
232  int ret = 0;
233 
234  if (!fifo->root.next) {
235  if ((ret = ff_request_frame(outlink->src->inputs[0])) < 0) {
236  if (ret == AVERROR_EOF && outlink->request_samples)
237  return return_audio_frame(outlink->src);
238  return ret;
239  }
240  av_assert0(fifo->root.next);
241  }
242 
243  if (outlink->request_samples) {
244  return return_audio_frame(outlink->src);
245  } else {
246  ret = ff_filter_frame(outlink, fifo->root.next->frame);
247  queue_pop(fifo);
248  }
249 
250  return ret;
251 }
252 
254  {
255  .name = "default",
256  .type = AVMEDIA_TYPE_VIDEO,
257  .filter_frame = add_to_queue,
258  },
259  { NULL }
260 };
261 
263  {
264  .name = "default",
265  .type = AVMEDIA_TYPE_VIDEO,
266  .request_frame = request_frame,
267  },
268  { NULL }
269 };
270 
272  .name = "fifo",
273  .description = NULL_IF_CONFIG_SMALL("Buffer input images and send them when they are requested."),
274 
275  .init = init,
276  .uninit = uninit,
277 
278  .priv_size = sizeof(FifoContext),
279 
280  .inputs = avfilter_vf_fifo_inputs,
281  .outputs = avfilter_vf_fifo_outputs,
282 };
283 
285  {
286  .name = "default",
287  .type = AVMEDIA_TYPE_AUDIO,
288  .filter_frame = add_to_queue,
289  },
290  { NULL }
291 };
292 
294  {
295  .name = "default",
296  .type = AVMEDIA_TYPE_AUDIO,
297  .request_frame = request_frame,
298  },
299  { NULL }
300 };
301 
303  .name = "afifo",
304  .description = NULL_IF_CONFIG_SMALL("Buffer input frames and send them when they are requested."),
305 
306  .init = init,
307  .uninit = uninit,
308 
309  .priv_size = sizeof(FifoContext),
310 
311  .inputs = avfilter_af_afifo_inputs,
312  .outputs = avfilter_af_afifo_outputs,
313 };