libavfilter/fifo.c - third_party/ffmpeg - Git at Google

 /*
  * Copyright (c) 2007 Bobby Bingham
  *
  * This file is part of FFmpeg.
  *
  * FFmpeg is free software; you can redistribute it and/or
  * modify it under the terms of the GNU Lesser General Public
  * License as published by the Free Software Foundation; either
  * version 2.1 of the License, or (at your option) any later version.
  *
  * FFmpeg is distributed in the hope that it will be useful,
  * but WITHOUT ANY WARRANTY; without even the implied warranty of
  * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
  * Lesser General Public License for more details.
  *
  * You should have received a copy of the GNU Lesser General Public
  * License along with FFmpeg; if not, write to the Free Software
  * Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA
  */

 /**
  * @file
  * FIFO buffering filter
  */

 #include "libavutil/avassert.h"
 #include "libavutil/audioconvert.h"
 #include "libavutil/common.h"
 #include "libavutil/mathematics.h"
 #include "libavutil/samplefmt.h"

 #include "audio.h"
 #include "avfilter.h"
 #include "internal.h"
 #include "video.h"

 typedef struct Buf {
     AVFilterBufferRef *buf;
     struct Buf        *next;
 } Buf;

 typedef struct {
     Buf  root;
     Buf *last;   ///< last buffered frame

     /**
      * When a specific number of output samples is requested, the partial
      * buffer is stored here
      */
     AVFilterBufferRef *buf_out;
     int allocated_samples;      ///< number of samples buf_out was allocated for
 } FifoContext;

 static av_cold int init(AVFilterContext *ctx, const char *args)
 {
     FifoContext *fifo = ctx->priv;
     fifo->last = &fifo->root;

     return 0;
 }

 static av_cold void uninit(AVFilterContext *ctx)
 {
     FifoContext *fifo = ctx->priv;
     Buf *buf, *tmp;

     for (buf = fifo->root.next; buf; buf = tmp) {
         tmp = buf->next;
         avfilter_unref_bufferp(&buf->buf);
         av_free(buf);
     }

     avfilter_unref_bufferp(&fifo->buf_out);
 }

 static int add_to_queue(AVFilterLink *inlink, AVFilterBufferRef *buf)
 {
     FifoContext *fifo = inlink->dst->priv;

     inlink->cur_buf = NULL;
     fifo->last->next = av_mallocz(sizeof(Buf));
     if (!fifo->last->next) {
         avfilter_unref_buffer(buf);
         return AVERROR(ENOMEM);
     }

     fifo->last = fifo->last->next;
     fifo->last->buf = buf;

     return 0;
 }

 static void queue_pop(FifoContext *s)
 {
     Buf *tmp = s->root.next->next;
     if (s->last == s->root.next)
         s->last = &s->root;
     av_freep(&s->root.next);
     s->root.next = tmp;
 }

 static int end_frame(AVFilterLink *inlink)
 {
     return 0;
 }

 static int draw_slice(AVFilterLink *inlink, int y, int h, int slice_dir)
 {
     return 0;
 }

 /**
  * Move data pointers and pts offset samples forward.
  */
 static void buffer_offset(AVFilterLink *link, AVFilterBufferRef *buf,
                           int offset)
 {
     int nb_channels = av_get_channel_layout_nb_channels(link->channel_layout);
     int planar = av_sample_fmt_is_planar(link->format);
     int planes = planar ? nb_channels : 1;
     int block_align = av_get_bytes_per_sample(link->format) * (planar ? 1 : nb_channels);
     int i;

     av_assert0(buf->audio->nb_samples > offset);

     for (i = 0; i < planes; i++)
         buf->extended_data[i] += block_align*offset;
     if (buf->data != buf->extended_data)
         memcpy(buf->data, buf->extended_data,
                FFMIN(planes, FF_ARRAY_ELEMS(buf->data)) * sizeof(*buf->data));
     buf->linesize[0] -= block_align*offset;
     buf->audio->nb_samples -= offset;

     if (buf->pts != AV_NOPTS_VALUE) {
         buf->pts += av_rescale_q(offset, (AVRational){1, link->sample_rate},
                                  link->time_base);
     }
 }

 static int calc_ptr_alignment(AVFilterBufferRef *buf)
 {
     int planes = av_sample_fmt_is_planar(buf->format) ?
                  av_get_channel_layout_nb_channels(buf->audio->channel_layout) : 1;
     int min_align = 128;
     int p;

     for (p = 0; p < planes; p++) {
         int cur_align = 128;
         while ((intptr_t)buf->extended_data[p] % cur_align)
             cur_align >>= 1;
         if (cur_align < min_align)
             min_align = cur_align;
     }
     return min_align;
 }

 static int return_audio_frame(AVFilterContext *ctx)
 {
     AVFilterLink *link = ctx->outputs[0];
     FifoContext *s = ctx->priv;
     AVFilterBufferRef *head = s->root.next->buf;
     AVFilterBufferRef *buf_out;
     int ret;

     if (!s->buf_out &&
         head->audio->nb_samples >= link->request_samples &&
         calc_ptr_alignment(head) >= 32) {
         if (head->audio->nb_samples == link->request_samples) {
             buf_out = head;
             queue_pop(s);
         } else {
             buf_out = avfilter_ref_buffer(head, AV_PERM_READ);
             if (!buf_out)
                 return AVERROR(ENOMEM);

             buf_out->audio->nb_samples = link->request_samples;
             buffer_offset(link, head, link->request_samples);
         }
     } else {
         int nb_channels = av_get_channel_layout_nb_channels(link->channel_layout);

         if (!s->buf_out) {
             s->buf_out = ff_get_audio_buffer(link, AV_PERM_WRITE,
                                              link->request_samples);
             if (!s->buf_out)
                 return AVERROR(ENOMEM);

             s->buf_out->audio->nb_samples = 0;
             s->buf_out->pts               = head->pts;
             s->allocated_samples          = link->request_samples;
         } else if (link->request_samples != s->allocated_samples) {
             av_log(ctx, AV_LOG_ERROR, "request_samples changed before the "
                    "buffer was returned.\n");
             return AVERROR(EINVAL);
         }

         while (s->buf_out->audio->nb_samples < s->allocated_samples) {
             int len = FFMIN(s->allocated_samples - s->buf_out->audio->nb_samples,
                             head->audio->nb_samples);

             av_samples_copy(s->buf_out->extended_data, head->extended_data,
                             s->buf_out->audio->nb_samples, 0, len, nb_channels,
                             link->format);
             s->buf_out->audio->nb_samples += len;

             if (len == head->audio->nb_samples) {
                 avfilter_unref_buffer(head);
                 queue_pop(s);

                 if (!s->root.next &&
                     (ret = ff_request_frame(ctx->inputs[0])) < 0) {
                     if (ret == AVERROR_EOF) {
                         av_samples_set_silence(s->buf_out->extended_data,
                                                s->buf_out->audio->nb_samples,
                                                s->allocated_samples -
                                                s->buf_out->audio->nb_samples,
                                                nb_channels, link->format);
                         s->buf_out->audio->nb_samples = s->allocated_samples;
                         break;
                     }
                     return ret;
                 }
                 head = s->root.next->buf;
             } else {
                 buffer_offset(link, head, len);
             }
         }
         buf_out = s->buf_out;
         s->buf_out = NULL;
     }
     return ff_filter_samples(link, buf_out);
 }

 static int request_frame(AVFilterLink *outlink)
 {
     FifoContext *fifo = outlink->src->priv;
     int ret = 0;

     if (!fifo->root.next) {
         if ((ret = ff_request_frame(outlink->src->inputs[0])) < 0)
             return ret;
     }

     /* by doing this, we give ownership of the reference to the next filter,
      * so we don't have to worry about dereferencing it ourselves. */
     switch (outlink->type) {
     case AVMEDIA_TYPE_VIDEO:
         if ((ret = ff_start_frame(outlink, fifo->root.next->buf)) < 0 ||
             (ret = ff_draw_slice(outlink, 0, outlink->h, 1)) < 0 ||
             (ret = ff_end_frame(outlink)) < 0)
             return ret;

         queue_pop(fifo);
         break;
     case AVMEDIA_TYPE_AUDIO:
         if (outlink->request_samples) {
             return return_audio_frame(outlink->src);
         } else {
             ret = ff_filter_samples(outlink, fifo->root.next->buf);
             queue_pop(fifo);
         }
         break;
     default:
         return AVERROR(EINVAL);
     }

     return ret;
 }

 AVFilter avfilter_vf_fifo = {
     .name      = "fifo",
     .description = NULL_IF_CONFIG_SMALL("Buffer input images and send them when they are requested."),

     .init      = init,
     .uninit    = uninit,

     .priv_size = sizeof(FifoContext),

     .inputs    = (const AVFilterPad[]) {{ .name            = "default",
                                           .type            = AVMEDIA_TYPE_VIDEO,
                                           .get_video_buffer= ff_null_get_video_buffer,
                                           .start_frame     = add_to_queue,
                                           .draw_slice      = draw_slice,
                                           .end_frame       = end_frame,
                                           .min_perms       = AV_PERM_PRESERVE, },
                                         { .name = NULL}},
     .outputs   = (const AVFilterPad[]) {{ .name            = "default",
                                           .type            = AVMEDIA_TYPE_VIDEO,
                                           .request_frame   = request_frame, },
                                         { .name = NULL}},
 };

 AVFilter avfilter_af_afifo = {
     .name        = "afifo",
     .description = NULL_IF_CONFIG_SMALL("Buffer input frames and send them when they are requested."),

     .init      = init,
     .uninit    = uninit,

     .priv_size = sizeof(FifoContext),

     .inputs    = (const AVFilterPad[]) {{ .name             = "default",
                                           .type             = AVMEDIA_TYPE_AUDIO,
                                           .get_audio_buffer = ff_null_get_audio_buffer,
                                           .filter_samples   = add_to_queue,
                                           .min_perms        = AV_PERM_PRESERVE, },
                                         { .name = NULL}},
     .outputs   = (const AVFilterPad[]) {{ .name             = "default",
                                           .type             = AVMEDIA_TYPE_AUDIO,
                                           .request_frame    = request_frame, },
                                         { .name = NULL}},
 };
	/*
	* Copyright (c) 2007 Bobby Bingham
	*
	* This file is part of FFmpeg.
	*
	* FFmpeg is free software; you can redistribute it and/or
	* modify it under the terms of the GNU Lesser General Public
	* License as published by the Free Software Foundation; either
	* version 2.1 of the License, or (at your option) any later version.
	*
	* FFmpeg is distributed in the hope that it will be useful,
	* but WITHOUT ANY WARRANTY; without even the implied warranty of
	* MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
	* Lesser General Public License for more details.
	*
	* You should have received a copy of the GNU Lesser General Public
	* License along with FFmpeg; if not, write to the Free Software
	* Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA
	*/

	/**
	* @file
	* FIFO buffering filter
	*/

	#include "libavutil/avassert.h"
	#include "libavutil/audioconvert.h"
	#include "libavutil/common.h"
	#include "libavutil/mathematics.h"
	#include "libavutil/samplefmt.h"

	#include "audio.h"
	#include "avfilter.h"
	#include "internal.h"
	#include "video.h"

	typedef struct Buf {
	AVFilterBufferRef *buf;
	struct Buf *next;
	} Buf;

	typedef struct {
	Buf root;
	Buf *last; ///< last buffered frame

	/**
	* When a specific number of output samples is requested, the partial
	* buffer is stored here
	*/
	AVFilterBufferRef *buf_out;
	int allocated_samples; ///< number of samples buf_out was allocated for
	} FifoContext;

	static av_cold int init(AVFilterContext ctx, const char args)
	{
	FifoContext *fifo = ctx->priv;
	fifo->last = &fifo->root;

	return 0;
	}

	static av_cold void uninit(AVFilterContext *ctx)
	{
	FifoContext *fifo = ctx->priv;
	Buf buf, tmp;

	for (buf = fifo->root.next; buf; buf = tmp) {
	tmp = buf->next;
	avfilter_unref_bufferp(&buf->buf);
	av_free(buf);
	}

	avfilter_unref_bufferp(&fifo->buf_out);
	}

	static int add_to_queue(AVFilterLink inlink, AVFilterBufferRef buf)
	{
	FifoContext *fifo = inlink->dst->priv;

	inlink->cur_buf = NULL;
	fifo->last->next = av_mallocz(sizeof(Buf));
	if (!fifo->last->next) {
	avfilter_unref_buffer(buf);
	return AVERROR(ENOMEM);
	}

	fifo->last = fifo->last->next;
	fifo->last->buf = buf;

	return 0;
	}

	static void queue_pop(FifoContext *s)
	{
	Buf *tmp = s->root.next->next;
	if (s->last == s->root.next)
	s->last = &s->root;
	av_freep(&s->root.next);
	s->root.next = tmp;
	}

	static int end_frame(AVFilterLink *inlink)
	{
	return 0;
	}

	static int draw_slice(AVFilterLink *inlink, int y, int h, int slice_dir)
	{
	return 0;
	}

	/**
	* Move data pointers and pts offset samples forward.
	*/
	static void buffer_offset(AVFilterLink link, AVFilterBufferRef buf,
	int offset)
	{
	int nb_channels = av_get_channel_layout_nb_channels(link->channel_layout);
	int planar = av_sample_fmt_is_planar(link->format);
	int planes = planar ? nb_channels : 1;
	int block_align = av_get_bytes_per_sample(link->format) * (planar ? 1 : nb_channels);
	int i;

	av_assert0(buf->audio->nb_samples > offset);

	for (i = 0; i < planes; i++)
	buf->extended_data[i] += block_align*offset;
	if (buf->data != buf->extended_data)
	memcpy(buf->data, buf->extended_data,
	FFMIN(planes, FF_ARRAY_ELEMS(buf->data)) * sizeof(*buf->data));
	buf->linesize[0] -= block_align*offset;
	buf->audio->nb_samples -= offset;

	if (buf->pts != AV_NOPTS_VALUE) {
	buf->pts += av_rescale_q(offset, (AVRational){1, link->sample_rate},
	link->time_base);
	}
	}

	static int calc_ptr_alignment(AVFilterBufferRef *buf)
	{
	int planes = av_sample_fmt_is_planar(buf->format) ?
	av_get_channel_layout_nb_channels(buf->audio->channel_layout) : 1;
	int min_align = 128;
	int p;

	for (p = 0; p < planes; p++) {
	int cur_align = 128;
	while ((intptr_t)buf->extended_data[p] % cur_align)
	cur_align >>= 1;
	if (cur_align < min_align)
	min_align = cur_align;
	}
	return min_align;
	}

	static int return_audio_frame(AVFilterContext *ctx)
	{
	AVFilterLink *link = ctx->outputs[0];
	FifoContext *s = ctx->priv;
	AVFilterBufferRef *head = s->root.next->buf;
	AVFilterBufferRef *buf_out;
	int ret;

	if (!s->buf_out &&
	head->audio->nb_samples >= link->request_samples &&
	calc_ptr_alignment(head) >= 32) {
	if (head->audio->nb_samples == link->request_samples) {
	buf_out = head;
	queue_pop(s);
	} else {
	buf_out = avfilter_ref_buffer(head, AV_PERM_READ);
	if (!buf_out)
	return AVERROR(ENOMEM);

	buf_out->audio->nb_samples = link->request_samples;
	buffer_offset(link, head, link->request_samples);
	}
	} else {
	int nb_channels = av_get_channel_layout_nb_channels(link->channel_layout);

	if (!s->buf_out) {
	s->buf_out = ff_get_audio_buffer(link, AV_PERM_WRITE,
	link->request_samples);
	if (!s->buf_out)
	return AVERROR(ENOMEM);

	s->buf_out->audio->nb_samples = 0;
	s->buf_out->pts = head->pts;
	s->allocated_samples = link->request_samples;
	} else if (link->request_samples != s->allocated_samples) {
	av_log(ctx, AV_LOG_ERROR, "request_samples changed before the "
	"buffer was returned.\n");
	return AVERROR(EINVAL);
	}

	while (s->buf_out->audio->nb_samples < s->allocated_samples) {
	int len = FFMIN(s->allocated_samples - s->buf_out->audio->nb_samples,
	head->audio->nb_samples);

	av_samples_copy(s->buf_out->extended_data, head->extended_data,
	s->buf_out->audio->nb_samples, 0, len, nb_channels,
	link->format);
	s->buf_out->audio->nb_samples += len;

	if (len == head->audio->nb_samples) {
	avfilter_unref_buffer(head);
	queue_pop(s);

	if (!s->root.next &&
	(ret = ff_request_frame(ctx->inputs[0])) < 0) {
	if (ret == AVERROR_EOF) {
	av_samples_set_silence(s->buf_out->extended_data,
	s->buf_out->audio->nb_samples,
	s->allocated_samples -
	s->buf_out->audio->nb_samples,
	nb_channels, link->format);
	s->buf_out->audio->nb_samples = s->allocated_samples;
	break;
	}
	return ret;
	}
	head = s->root.next->buf;
	} else {
	buffer_offset(link, head, len);
	}
	}
	buf_out = s->buf_out;
	s->buf_out = NULL;
	}
	return ff_filter_samples(link, buf_out);
	}

	static int request_frame(AVFilterLink *outlink)
	{
	FifoContext *fifo = outlink->src->priv;
	int ret = 0;

	if (!fifo->root.next) {
	if ((ret = ff_request_frame(outlink->src->inputs[0])) < 0)
	return ret;
	}

	/* by doing this, we give ownership of the reference to the next filter,
	* so we don't have to worry about dereferencing it ourselves. */
	switch (outlink->type) {
	case AVMEDIA_TYPE_VIDEO:
	if ((ret = ff_start_frame(outlink, fifo->root.next->buf)) < 0 \|\|
	(ret = ff_draw_slice(outlink, 0, outlink->h, 1)) < 0 \|\|
	(ret = ff_end_frame(outlink)) < 0)
	return ret;

	queue_pop(fifo);
	break;
	case AVMEDIA_TYPE_AUDIO:
	if (outlink->request_samples) {
	return return_audio_frame(outlink->src);
	} else {
	ret = ff_filter_samples(outlink, fifo->root.next->buf);
	queue_pop(fifo);
	}
	break;
	default:
	return AVERROR(EINVAL);
	}

	return ret;
	}

	AVFilter avfilter_vf_fifo = {
	.name = "fifo",
	.description = NULL_IF_CONFIG_SMALL("Buffer input images and send them when they are requested."),

	.init = init,
	.uninit = uninit,

	.priv_size = sizeof(FifoContext),

	.inputs = (const AVFilterPad[]) {{ .name = "default",
	.type = AVMEDIA_TYPE_VIDEO,
	.get_video_buffer= ff_null_get_video_buffer,
	.start_frame = add_to_queue,
	.draw_slice = draw_slice,
	.end_frame = end_frame,
	.min_perms = AV_PERM_PRESERVE, },
	{ .name = NULL}},
	.outputs = (const AVFilterPad[]) {{ .name = "default",
	.type = AVMEDIA_TYPE_VIDEO,
	.request_frame = request_frame, },
	{ .name = NULL}},
	};

	AVFilter avfilter_af_afifo = {
	.name = "afifo",
	.description = NULL_IF_CONFIG_SMALL("Buffer input frames and send them when they are requested."),

	.init = init,
	.uninit = uninit,

	.priv_size = sizeof(FifoContext),

	.inputs = (const AVFilterPad[]) {{ .name = "default",
	.type = AVMEDIA_TYPE_AUDIO,
	.get_audio_buffer = ff_null_get_audio_buffer,
	.filter_samples = add_to_queue,
	.min_perms = AV_PERM_PRESERVE, },
	{ .name = NULL}},
	.outputs = (const AVFilterPad[]) {{ .name = "default",
	.type = AVMEDIA_TYPE_AUDIO,
	.request_frame = request_frame, },
	{ .name = NULL}},
	};