libavcodec/audio_frame_queue.c

   1 /*
   2  * Audio Frame Queue
   3  * Copyright (c) 2012 Justin Ruggles
   4  *
   5  * This file is part of Libav.
   6  *
   7  * Libav 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  * Libav 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 Libav; 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/common.h"
  23 #include "libavutil/mathematics.h"
  24 #include "internal.h"
  25 #include "audio_frame_queue.h"
  26
  27 void ff_af_queue_init(AVCodecContext *avctx, AudioFrameQueue *afq)
  28 {
  29     afq->avctx             = avctx;
  30     afq->next_pts          = AV_NOPTS_VALUE;
  31     afq->remaining_delay   = avctx->delay;
  32     afq->remaining_samples = avctx->delay;
  33     afq->frame_queue       = NULL;
  34 }
  35
  36 static void delete_next_frame(AudioFrameQueue *afq)
  37 {
  38     AudioFrame *f = afq->frame_queue;
  39     if (f) {
  40         afq->frame_queue = f->next;
  41         f->next = NULL;
  42         av_freep(&f);
  43     }
  44 }
  45
  46 void ff_af_queue_close(AudioFrameQueue *afq)
  47 {
  48     /* remove/free any remaining frames */
  49     while (afq->frame_queue)
  50         delete_next_frame(afq);
  51     memset(afq, 0, sizeof(*afq));
  52 }
  53
  54 #ifdef DEBUG
  55 static void af_queue_log_state(AudioFrameQueue *afq)
  56 {
  57     AudioFrame *f;
  58     av_dlog(afq->avctx, "remaining delay   = %d\n", afq->remaining_delay);
  59     av_dlog(afq->avctx, "remaining samples = %d\n", afq->remaining_samples);
  60     av_dlog(afq->avctx, "frames:\n");
  61     f = afq->frame_queue;
  62     while (f) {
  63         av_dlog(afq->avctx, "  [ pts=%9"PRId64" duration=%d ]\n",
  64                 f->pts, f->duration);
  65         f = f->next;
  66     }
  67 }
  68 #endif /* DEBUG */
  69
  70 int ff_af_queue_add(AudioFrameQueue *afq, const AVFrame *f)
  71 {
  72     AudioFrame *new_frame;
  73     AudioFrame *queue_end = afq->frame_queue;
  74
  75     /* find the end of the queue */
  76     while (queue_end && queue_end->next)
  77         queue_end = queue_end->next;
  78
  79     /* allocate new frame queue entry */
  80     if (!(new_frame = av_malloc(sizeof(*new_frame))))
  81         return AVERROR(ENOMEM);
  82
  83     /* get frame parameters */
  84     new_frame->next = NULL;
  85     new_frame->duration = f->nb_samples;
  86     if (f->pts != AV_NOPTS_VALUE) {
  87         new_frame->pts = av_rescale_q(f->pts,
  88                                       afq->avctx->time_base,
  89                                       (AVRational){ 1, afq->avctx->sample_rate });
  90         afq->next_pts = new_frame->pts + new_frame->duration;
  91     } else {
  92         new_frame->pts = AV_NOPTS_VALUE;
  93         afq->next_pts  = AV_NOPTS_VALUE;
  94     }
  95
  96     /* add new frame to the end of the queue */
  97     if (!queue_end)
  98         afq->frame_queue = new_frame;
  99     else
 100         queue_end->next = new_frame;
 101
 102     /* add frame sample count */
 103     afq->remaining_samples += f->nb_samples;
 104
 105 #ifdef DEBUG
 106     af_queue_log_state(afq);
 107 #endif
 108
 109     return 0;
 110 }
 111
 112 void ff_af_queue_remove(AudioFrameQueue *afq, int nb_samples, int64_t *pts,
 113                         int *duration)
 114 {
 115     int64_t out_pts = AV_NOPTS_VALUE;
 116     int removed_samples = 0;
 117
 118 #ifdef DEBUG
 119     af_queue_log_state(afq);
 120 #endif
 121
 122     /* get output pts from the next frame or generated pts */
 123     if (afq->frame_queue) {
 124         if (afq->frame_queue->pts != AV_NOPTS_VALUE)
 125             out_pts = afq->frame_queue->pts - afq->remaining_delay;
 126     } else {
 127         if (afq->next_pts != AV_NOPTS_VALUE)
 128             out_pts = afq->next_pts - afq->remaining_delay;
 129     }
 130     if (pts) {
 131         if (out_pts != AV_NOPTS_VALUE)
 132             *pts = ff_samples_to_time_base(afq->avctx, out_pts);
 133         else
 134             *pts = AV_NOPTS_VALUE;
 135     }
 136
 137     /* if the delay is larger than the packet duration, we use up delay samples
 138        for the output packet and leave all frames in the queue */
 139     if (afq->remaining_delay >= nb_samples) {
 140         removed_samples      += nb_samples;
 141         afq->remaining_delay -= nb_samples;
 142     }
 143     /* remove frames from the queue until we have enough to cover the
 144        requested number of samples or until the queue is empty */
 145     while (removed_samples < nb_samples && afq->frame_queue) {
 146         removed_samples += afq->frame_queue->duration;
 147         delete_next_frame(afq);
 148     }
 149     afq->remaining_samples -= removed_samples;
 150
 151     /* if there are no frames left and we have room for more samples, use
 152        any remaining delay samples */
 153     if (removed_samples < nb_samples && afq->remaining_samples > 0) {
 154         int add_samples = FFMIN(afq->remaining_samples,
 155                                 nb_samples - removed_samples);
 156         removed_samples        += add_samples;
 157         afq->remaining_samples -= add_samples;
 158     }
 159     if (removed_samples > nb_samples)
 160         av_log(afq->avctx, AV_LOG_WARNING, "frame_size is too large\n");
 161     if (duration)
 162         *duration = ff_samples_to_time_base(afq->avctx, removed_samples);
 163 }