FFmpeg: libavcodec/audio_frame_queue.c Source File

FFmpeg
audio_frame_queue.c
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1 /*
2  * Audio Frame Queue
3  * Copyright (c) 2012 Justin Ruggles
4  *
5  * This file is part of FFmpeg.
6  *
7  * FFmpeg is free software; you can redistribute it and/or
8  * modify it under the terms of the GNU Lesser General Public
9  * License as published by the Free Software Foundation; either
10  * version 2.1 of the License, or (at your option) any later version.
11  *
12  * FFmpeg is distributed in the hope that it will be useful,
13  * but WITHOUT ANY WARRANTY; without even the implied warranty of
14  * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
15  * Lesser General Public License for more details.
16  *
17  * You should have received a copy of the GNU Lesser General Public
18  * License along with FFmpeg; if not, write to the Free Software
19  * Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA
20  */
21 
22 #include "libavutil/attributes.h"
23 #include "libavutil/common.h"
24 #include "audio_frame_queue.h"
25 #include "internal.h"
26 #include "libavutil/avassert.h"
27 
28  av_cold void ff_af_queue_init(AVCodecContext *avctx, AudioFrameQueue *afq)
29 {
30  afq->avctx = avctx;
31  afq->remaining_delay = avctx->initial_padding;
32  afq->remaining_samples = avctx->initial_padding;
33  afq->frame_count = 0;
34 }
35 
36  void ff_af_queue_close(AudioFrameQueue *afq)
37 {
38  if(afq->frame_count)
39  av_log(afq->avctx, AV_LOG_WARNING, "%d frames left in the queue on closing\n", afq->frame_count);
40  av_freep(&afq->frames);
41  memset(afq, 0, sizeof(*afq));
42 }
43 
44  int ff_af_queue_add(AudioFrameQueue *afq, const AVFrame *f)
45 {
46  AudioFrame *new = av_fast_realloc(afq->frames, &afq->frame_alloc, sizeof(*afq->frames)*(afq->frame_count+1));
47  if(!new)
48  return AVERROR(ENOMEM);
49  afq->frames = new;
50  new += afq->frame_count;
51 
52  /* get frame parameters */
53  new->duration = f->nb_samples;
54  new->duration += afq->remaining_delay;
55  if (f->pts != AV_NOPTS_VALUE) {
56  new->pts = av_rescale_q(f->pts,
57  afq->avctx->time_base,
58  (AVRational){ 1, afq->avctx->sample_rate });
59  new->pts -= afq->remaining_delay;
60  if(afq->frame_count && new[-1].pts >= new->pts)
61  av_log(afq->avctx, AV_LOG_WARNING, "Queue input is backward in time\n");
62  } else {
63  new->pts = AV_NOPTS_VALUE;
64  }
65  afq->remaining_delay = 0;
66 
67  /* add frame sample count */
68  afq->remaining_samples += f->nb_samples;
69 
70  afq->frame_count++;
71 
72  return 0;
73 }
74 
75  void ff_af_queue_remove(AudioFrameQueue *afq, int nb_samples, int64_t *pts,
76  int64_t *duration)
77 {
78  int64_t out_pts = AV_NOPTS_VALUE;
79  int removed_samples = 0;
80  int i;
81 
82  if (afq->frame_count || afq->frame_alloc) {
83  if (afq->frames->pts != AV_NOPTS_VALUE)
84  out_pts = afq->frames->pts;
85  }
86  if(!afq->frame_count)
87  av_log(afq->avctx, AV_LOG_WARNING, "Trying to remove %d samples, but the queue is empty\n", nb_samples);
88  if (pts)
89  *pts = ff_samples_to_time_base(afq->avctx, out_pts);
90 
91  for(i=0; nb_samples && i<afq->frame_count; i++){
92  int n= FFMIN(afq->frames[i].duration, nb_samples);
93  afq->frames[i].duration -= n;
94  nb_samples -= n;
95  removed_samples += n;
96  if(afq->frames[i].pts != AV_NOPTS_VALUE)
97  afq->frames[i].pts += n;
98  }
99  afq->remaining_samples -= removed_samples;
100  i -= i && afq->frames[i-1].duration;
101  memmove(afq->frames, afq->frames + i, sizeof(*afq->frames) * (afq->frame_count - i));
102  afq->frame_count -= i;
103 
104  if(nb_samples){
105  av_assert0(!afq->frame_count);
106  av_assert0(afq->remaining_samples == afq->remaining_delay);
107  if(afq->frames && afq->frames[0].pts != AV_NOPTS_VALUE)
108  afq->frames[0].pts += nb_samples;
109  av_log(afq->avctx, AV_LOG_DEBUG, "Trying to remove %d more samples than there are in the queue\n", nb_samples);
110  }
111  if (duration)
112  *duration = ff_samples_to_time_base(afq->avctx, removed_samples);
113 }
ff_af_queue_remove
void ff_af_queue_remove(AudioFrameQueue *afq, int nb_samples, int64_t *pts, int64_t *duration)
Remove frame(s) from the queue.
Definition: audio_frame_queue.c:75
AVFrame
This structure describes decoded (raw) audio or video data.
Definition: frame.h:181
AV_LOG_WARNING
#define AV_LOG_WARNING
Something somehow does not look correct.
Definition: log.h:182
AudioFrame::pts
int64_t pts
Definition: audio_frame_queue.h:28
AudioFrameQueue::frames
AudioFrame * frames
Definition: audio_frame_queue.h:36
attributes.h
Macro definitions for various function/variable attributes.
AVCodecContext::time_base
AVRational time_base
This is the fundamental unit of time (in seconds) in terms of which frame timestamps are represented...
Definition: avcodec.h:1661
av_assert0
#define av_assert0(cond)
assert() equivalent, that is always enabled.
Definition: avassert.h:37
av_cold
#define av_cold
Definition: attributes.h:82
ff_af_queue_init
av_cold void ff_af_queue_init(AVCodecContext *avctx, AudioFrameQueue *afq)
Initialize AudioFrameQueue.
Definition: audio_frame_queue.c:28
AVFrame::pts
int64_t pts
Presentation timestamp in time_base units (time when frame should be shown to user).
Definition: frame.h:262
av_log
#define av_log(a,...)
Definition: tableprint_vlc.h:28
av_rescale_q
int64_t av_rescale_q(int64_t a, AVRational bq, AVRational cq)
Rescale a 64-bit integer by 2 rational numbers.
Definition: mathematics.c:142
av_fast_realloc
void * av_fast_realloc(void *ptr, unsigned int *size, size_t min_size)
Reallocate the given block if it is not large enough, otherwise do nothing.
Definition: mem.c:480
AVERROR
#define AVERROR(e)
Definition: error.h:43
AVCodecContext::initial_padding
int initial_padding
Audio only.
Definition: avcodec.h:3204
AV_LOG_DEBUG
#define AV_LOG_DEBUG
Stuff which is only useful for libav* developers.
Definition: log.h:197
avassert.h
simple assert() macros that are a bit more flexible than ISO C assert().
ff_af_queue_add
int ff_af_queue_add(AudioFrameQueue *afq, const AVFrame *f)
Add a frame to the queue.
Definition: audio_frame_queue.c:44
AudioFrameQueue::avctx
AVCodecContext * avctx
Definition: audio_frame_queue.h:33
FFMIN
#define FFMIN(a, b)
Definition: common.h:96
duration
int64_t duration
Definition: movenc-test.c:63
n
int n
Definition: avisynth_c.h:547
AudioFrameQueue::frame_count
unsigned frame_count
Definition: audio_frame_queue.h:37
AVCodecContext::sample_rate
int sample_rate
samples per second
Definition: avcodec.h:2287
AudioFrameQueue::frame_alloc
unsigned frame_alloc
Definition: audio_frame_queue.h:38
AVCodecContext
main external API structure.
Definition: avcodec.h:1532
AVRational
rational number numerator/denominator
Definition: rational.h:43
pts
static int64_t pts
Global timestamp for the audio frames.
Definition: transcode_aac.c:547
audio_frame_queue.h
internal.h
common internal api header.
common.h
common internal and external API header
ff_af_queue_close
void ff_af_queue_close(AudioFrameQueue *afq)
Close AudioFrameQueue.
Definition: audio_frame_queue.c:36
av_freep
#define av_freep(p)
Definition: tableprint_vlc.h:35
ff_samples_to_time_base
static av_always_inline int64_t ff_samples_to_time_base(AVCodecContext *avctx, int64_t samples)
Rescale from sample rate to AVCodecContext.time_base.
Definition: internal.h:235
AVFrame::nb_samples
int nb_samples
number of audio samples (per channel) described by this frame
Definition: frame.h:235
AV_NOPTS_VALUE
#define AV_NOPTS_VALUE
Undefined timestamp value.
Definition: avutil.h:240
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