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/*

 * 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/channel_layout.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 {

    AVFrame *frame;

    struct Buf        *next;

} Buf;

typedef struct FifoContext {

    Buf  root;

    Buf *last;   ///< last buffered frame

    /**

     * When a specific number of output samples is requested, the partial

     * buffer is stored here

     */

    AVFrame *out;

    int allocated_samples;      ///< number of samples out was allocated for

} FifoContext;

static av_cold int init(AVFilterContext *ctx)

{

    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;

        av_frame_free(&buf->frame);

        av_free(buf);

    }

    av_frame_free(&fifo->out);

}

static int add_to_queue(AVFilterLink *inlink, AVFrame *frame)

{

    FifoContext *fifo = inlink->dst->priv;

    fifo->last->next = av_mallocz(sizeof(Buf));

    if (!fifo->last->next) {

        av_frame_free(&frame);

        return AVERROR(ENOMEM);

    }

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

    fifo->last->frame = frame;

    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;

}

/**

 * Move data pointers and pts offset samples forward.

 */

static void buffer_offset(AVFilterLink *link, AVFrame *frame,

                          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(frame->nb_samples > offset);

    for (i = 0; i < planes; i++)

        frame->extended_data[i] += block_align * offset;

    if (frame->data != frame->extended_data)

        memcpy(frame->data, frame->extended_data,

               FFMIN(planes, FF_ARRAY_ELEMS(frame->data)) * sizeof(*frame->data));

    frame->linesize[0] -= block_align*offset;

    frame->nb_samples -= offset;

    if (frame->pts != AV_NOPTS_VALUE) {

        frame->pts += av_rescale_q(offset, (AVRational){1, link->sample_rate},

                                   link->time_base);

    }

}

static int calc_ptr_alignment(AVFrame *frame)

{

    int planes = av_sample_fmt_is_planar(frame->format) ?

                 av_get_channel_layout_nb_channels(frame->channel_layout) : 1;

    int min_align = 128;

    int p;

    for (p = 0; p < planes; p++) {

        int cur_align = 128;

        while ((intptr_t)frame->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;

    AVFrame *head = s->root.next ? s->root.next->frame : NULL;

    AVFrame *out;

    int ret;

    /* if head is NULL then we're flushing the remaining samples in out */

    if (!head && !s->out)

        return AVERROR_EOF;

    if (!s->out &&

        head->nb_samples >= link->request_samples &&

        calc_ptr_alignment(head) >= 32) {

        if (head->nb_samples == link->request_samples) {

            out = head;

            queue_pop(s);

        } else {

            out = av_frame_clone(head);

            if (!out)

                return AVERROR(ENOMEM);

            out->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->out) {

            s->out = ff_get_audio_buffer(link, link->request_samples);

            if (!s->out)

                return AVERROR(ENOMEM);

            s->out->nb_samples = 0;

            s->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->out->nb_samples < s->allocated_samples) {

            int len;

            if (!s->root.next) {

                ret = ff_request_frame(ctx->inputs[0]);

                if (ret == AVERROR_EOF) {

                    av_samples_set_silence(s->out->extended_data,

                                           s->out->nb_samples,

                                           s->allocated_samples -

                                           s->out->nb_samples,

                                           nb_channels, link->format);

                    s->out->nb_samples = s->allocated_samples;

                    break;

                } else if (ret < 0)

                    return ret;

                av_assert0(s->root.next); // If ff_request_frame() succeeded then we should have a frame

            }

            head = s->root.next->frame;

            len = FFMIN(s->allocated_samples - s->out->nb_samples,

                        head->nb_samples);

            av_samples_copy(s->out->extended_data, head->extended_data,

                            s->out->nb_samples, 0, len, nb_channels,

                            link->format);

            s->out->nb_samples += len;

            if (len == head->nb_samples) {

                av_frame_free(&head);

                queue_pop(s);

            } else {

                buffer_offset(link, head, len);

            }

        }

        out = s->out;

        s->out = NULL;

    }

    return ff_filter_frame(link, 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) {

            if (ret == AVERROR_EOF && outlink->request_samples)

                return return_audio_frame(outlink->src);

            return ret;

        }

        av_assert0(fifo->root.next);

    }

    if (outlink->request_samples) {

        return return_audio_frame(outlink->src);

    } else {

        ret = ff_filter_frame(outlink, fifo->root.next->frame);

        queue_pop(fifo);

    }

    return ret;

}

static const AVFilterPad avfilter_vf_fifo_inputs[] = {

    {

        .name             = "default",

        .type             = AVMEDIA_TYPE_VIDEO,

        .filter_frame     = add_to_queue,

    },

    { NULL }

};

static const AVFilterPad avfilter_vf_fifo_outputs[] = {

    {

        .name          = "default",

        .type          = AVMEDIA_TYPE_VIDEO,

        .request_frame = request_frame,

    },

    { NULL }

};

AVFilter ff_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    = avfilter_vf_fifo_inputs,

    .outputs   = avfilter_vf_fifo_outputs,

};

static const AVFilterPad avfilter_af_afifo_inputs[] = {

    {

        .name             = "default",

        .type             = AVMEDIA_TYPE_AUDIO,

        .filter_frame     = add_to_queue,

    },

    { NULL }

};

static const AVFilterPad avfilter_af_afifo_outputs[] = {

    {

        .name          = "default",

        .type          = AVMEDIA_TYPE_AUDIO,

        .request_frame = request_frame,

    },

    { NULL }

};

AVFilter ff_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    = avfilter_af_afifo_inputs,

    .outputs   = avfilter_af_afifo_outputs,

};