/*
  * Copyright (c) 2011 Nicolas George <nicolas.george@normalesup.org>
  *
  * 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
  * Audio merging filter
  */
 

 #define FF_INTERNAL_FIELDS 1
 #include "framequeue.h"
 

 #include "libavutil/avstring.h"

 #include "libavutil/bprint.h"

 #include "libavutil/channel_layout.h"

 #include "libavutil/opt.h"

 #include "avfilter.h"

 #include "audio.h"

 #include "bufferqueue.h"

 #include "internal.h"
 

 #define SWR_CH_MAX 64

 typedef struct AMergeContext {

     const AVClass *class;
     int nb_inputs;

     int route[SWR_CH_MAX]; /**< channels routing, see copy_samples */
     int bps;

     struct amerge_input {
         struct FFBufQueue queue;

         int nb_ch;         /**< number of channels for the input */

         int nb_samples;
         int pos;

     } *in;

 } AMergeContext;
 

 #define OFFSET(x) offsetof(AMergeContext, x)

 #define FLAGS AV_OPT_FLAG_AUDIO_PARAM|AV_OPT_FLAG_FILTERING_PARAM

 
 static const AVOption amerge_options[] = {
     { "inputs", "specify the number of inputs", OFFSET(nb_inputs),

       AV_OPT_TYPE_INT, { .i64 = 2 }, 1, SWR_CH_MAX, FLAGS },

     { NULL }

 };
 

 AVFILTER_DEFINE_CLASS(amerge);

 static av_cold void uninit(AVFilterContext *ctx)
 {

     AMergeContext *s = ctx->priv;

     int i;

     for (i = 0; i < s->nb_inputs; i++) {
         if (s->in)
             ff_bufqueue_discard_all(&s->in[i].queue);

         if (ctx->input_pads)
             av_freep(&ctx->input_pads[i].name);

     }

     av_freep(&s->in);

 }
 
 static int query_formats(AVFilterContext *ctx)
 {

     AMergeContext *s = ctx->priv;

     int64_t inlayout[SWR_CH_MAX], outlayout = 0;

     AVFilterFormats *formats;

     AVFilterChannelLayouts *layouts;

     int i, ret, overlap = 0, nb_ch = 0;

     for (i = 0; i < s->nb_inputs; i++) {

         if (!ctx->inputs[i]->in_channel_layouts ||
             !ctx->inputs[i]->in_channel_layouts->nb_channel_layouts) {

             av_log(ctx, AV_LOG_WARNING,

                    "No channel layout for input %d\n", i + 1);

             return AVERROR(EAGAIN);

         }

         inlayout[i] = ctx->inputs[i]->in_channel_layouts->channel_layouts[0];
         if (ctx->inputs[i]->in_channel_layouts->nb_channel_layouts > 1) {

             char buf[256];
             av_get_channel_layout_string(buf, sizeof(buf), 0, inlayout[i]);
             av_log(ctx, AV_LOG_INFO, "Using \"%s\" for input %d\n", buf, i + 1);
         }

         s->in[i].nb_ch = FF_LAYOUT2COUNT(inlayout[i]);
         if (s->in[i].nb_ch) {

             overlap++;

         } else {
             s->in[i].nb_ch = av_get_channel_layout_nb_channels(inlayout[i]);
             if (outlayout & inlayout[i])
                 overlap++;
             outlayout |= inlayout[i];
         }

         nb_ch += s->in[i].nb_ch;

     }

     if (nb_ch > SWR_CH_MAX) {

         av_log(ctx, AV_LOG_ERROR, "Too many channels (max %d)\n", SWR_CH_MAX);
         return AVERROR(EINVAL);
     }

     if (overlap) {

         av_log(ctx, AV_LOG_WARNING,

                "Input channel layouts overlap: "
                "output layout will be determined by the number of distinct input channels\n");

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

             s->route[i] = i;

         outlayout = av_get_default_channel_layout(nb_ch);

         if (!outlayout && nb_ch)
             outlayout = 0xFFFFFFFFFFFFFFFFULL >> (64 - nb_ch);

     } else {

         int *route[SWR_CH_MAX];

         int c, out_ch_number = 0;
 

         route[0] = s->route;
         for (i = 1; i < s->nb_inputs; i++)
             route[i] = route[i - 1] + s->in[i - 1].nb_ch;

         for (c = 0; c < 64; c++)

             for (i = 0; i < s->nb_inputs; i++)

                 if ((inlayout[i] >> c) & 1)
                     *(route[i]++) = out_ch_number++;
     }

     formats = ff_make_format_list(ff_packed_sample_fmts_array);

     if ((ret = ff_set_common_formats(ctx, formats)) < 0)
         return ret;

     for (i = 0; i < s->nb_inputs; i++) {

         layouts = NULL;

         if ((ret = ff_add_channel_layout(&layouts, inlayout[i])) < 0)
             return ret;
         if ((ret = ff_channel_layouts_ref(layouts, &ctx->inputs[i]->out_channel_layouts)) < 0)
             return ret;

     }

     layouts = NULL;

     if ((ret = ff_add_channel_layout(&layouts, outlayout)) < 0)
         return ret;
     if ((ret = ff_channel_layouts_ref(layouts, &ctx->outputs[0]->in_channel_layouts)) < 0)
         return ret;
 
     return ff_set_common_samplerates(ctx, ff_all_samplerates());

 }
 
 static int config_output(AVFilterLink *outlink)
 {
     AVFilterContext *ctx = outlink->src;

     AMergeContext *s = ctx->priv;

     AVBPrint bp;

     int i;
 

     for (i = 1; i < s->nb_inputs; i++) {

         if (ctx->inputs[i]->sample_rate != ctx->inputs[0]->sample_rate) {
             av_log(ctx, AV_LOG_ERROR,
                    "Inputs must have the same sample rate "

                    "%d for in%d vs %d\n",

                    ctx->inputs[i]->sample_rate, i, ctx->inputs[0]->sample_rate);
             return AVERROR(EINVAL);
         }

     }

     s->bps = av_get_bytes_per_sample(ctx->outputs[0]->format);

     outlink->sample_rate = ctx->inputs[0]->sample_rate;
     outlink->time_base   = ctx->inputs[0]->time_base;

 
     av_bprint_init(&bp, 0, 1);

     for (i = 0; i < s->nb_inputs; i++) {

         av_bprintf(&bp, "%sin%d:", i ? " + " : "", i);
         av_bprint_channel_layout(&bp, -1, ctx->inputs[i]->channel_layout);

     }

     av_bprintf(&bp, " -> out:");
     av_bprint_channel_layout(&bp, -1, ctx->outputs[0]->channel_layout);

     av_log(ctx, AV_LOG_VERBOSE, "%s\n", bp.str);

     return 0;
 }
 
 static int request_frame(AVFilterLink *outlink)
 {
     AVFilterContext *ctx = outlink->src;

     AMergeContext *s = ctx->priv;

     int i, ret;

     for (i = 0; i < s->nb_inputs; i++)

         if (!s->in[i].nb_samples ||
             /* detect EOF immediately */
             (ctx->inputs[i]->status_in && !ctx->inputs[i]->status_out))

             if ((ret = ff_request_frame(ctx->inputs[i])) < 0)

                 return ret;

     return 0;
 }
 
 /**

  * Copy samples from several input streams to one output stream.
  * @param nb_inputs number of inputs

  * @param in        inputs; used only for the nb_ch field;

  * @param route     routing values;
  *                  input channel i goes to output channel route[i];

  *                  i <  in[0].nb_ch are the channels from the first output;
  *                  i >= in[0].nb_ch are the channels from the second output

  * @param ins       pointer to the samples of each inputs, in packed format;
  *                  will be left at the end of the copied samples
  * @param outs      pointer to the samples of the output, in packet format;
  *                  must point to a buffer big enough;
  *                  will be left at the end of the copied samples
  * @param ns        number of samples to copy
  * @param bps       bytes per sample
  */

 static inline void copy_samples(int nb_inputs, struct amerge_input in[],
                                 int *route, uint8_t *ins[],

                                 uint8_t **outs, int ns, int bps)
 {
     int *route_cur;

     int i, c, nb_ch = 0;

     for (i = 0; i < nb_inputs; i++)
         nb_ch += in[i].nb_ch;

     while (ns--) {
         route_cur = route;

         for (i = 0; i < nb_inputs; i++) {

             for (c = 0; c < in[i].nb_ch; c++) {

                 memcpy((*outs) + bps * *(route_cur++), ins[i], bps);
                 ins[i] += bps;
             }
         }

         *outs += nb_ch * bps;

     }
 }
 

 static int filter_frame(AVFilterLink *inlink, AVFrame *insamples)

 {
     AVFilterContext *ctx = inlink->dst;

     AMergeContext *s = ctx->priv;

     AVFilterLink *const outlink = ctx->outputs[0];

     int input_number;

     int nb_samples, ns, i;

     AVFrame *outbuf, *inbuf[SWR_CH_MAX];

     uint8_t *ins[SWR_CH_MAX], *outs;

     for (input_number = 0; input_number < s->nb_inputs; input_number++)

         if (inlink == ctx->inputs[input_number])
             break;

     av_assert1(input_number < s->nb_inputs);
     if (ff_bufqueue_is_full(&s->in[input_number].queue)) {

         av_frame_free(&insamples);

         return AVERROR(ENOMEM);
     }

     ff_bufqueue_add(ctx, &s->in[input_number].queue, av_frame_clone(insamples));
     s->in[input_number].nb_samples += insamples->nb_samples;

     av_frame_free(&insamples);

     nb_samples = s->in[0].nb_samples;
     for (i = 1; i < s->nb_inputs; i++)
         nb_samples = FFMIN(nb_samples, s->in[i].nb_samples);

     if (!nb_samples)

         return 0;

     outbuf = ff_get_audio_buffer(ctx->outputs[0], nb_samples);

     if (!outbuf)
         return AVERROR(ENOMEM);

     outs = outbuf->data[0];

     for (i = 0; i < s->nb_inputs; i++) {
         inbuf[i] = ff_bufqueue_peek(&s->in[i].queue, 0);

         ins[i] = inbuf[i]->data[0] +

                  s->in[i].pos * s->in[i].nb_ch * s->bps;

     }

     av_frame_copy_props(outbuf, inbuf[0]);

     outbuf->pts = inbuf[0]->pts == AV_NOPTS_VALUE ? AV_NOPTS_VALUE :
                   inbuf[0]->pts +

                   av_rescale_q(s->in[0].pos,

                                av_make_q(1, ctx->inputs[0]->sample_rate),

                                ctx->outputs[0]->time_base);

     outbuf->nb_samples     = nb_samples;
     outbuf->channel_layout = outlink->channel_layout;

     outbuf->channels       = outlink->channels;

     while (nb_samples) {
         ns = nb_samples;

         for (i = 0; i < s->nb_inputs; i++)
             ns = FFMIN(ns, inbuf[i]->nb_samples - s->in[i].pos);

         /* Unroll the most common sample formats: speed +~350% for the loop,
            +~13% overall (including two common decoders) */

         switch (s->bps) {

             case 1:

                 copy_samples(s->nb_inputs, s->in, s->route, ins, &outs, ns, 1);

                 break;
             case 2:

                 copy_samples(s->nb_inputs, s->in, s->route, ins, &outs, ns, 2);

                 break;
             case 4:

                 copy_samples(s->nb_inputs, s->in, s->route, ins, &outs, ns, 4);

                 break;
             default:

                 copy_samples(s->nb_inputs, s->in, s->route, ins, &outs, ns, s->bps);

                 break;
         }
 
         nb_samples -= ns;

         for (i = 0; i < s->nb_inputs; i++) {
             s->in[i].nb_samples -= ns;
             s->in[i].pos += ns;
             if (s->in[i].pos == inbuf[i]->nb_samples) {
                 s->in[i].pos = 0;

                 av_frame_free(&inbuf[i]);

                 ff_bufqueue_get(&s->in[i].queue);
                 inbuf[i] = ff_bufqueue_peek(&s->in[i].queue, 0);

                 ins[i] = inbuf[i] ? inbuf[i]->data[0] : NULL;

             }
         }
     }

     return ff_filter_frame(ctx->outputs[0], outbuf);

 }
 

 static av_cold int init(AVFilterContext *ctx)

 {

     AMergeContext *s = ctx->priv;

     int i, ret;

     s->in = av_calloc(s->nb_inputs, sizeof(*s->in));
     if (!s->in)

         return AVERROR(ENOMEM);

     for (i = 0; i < s->nb_inputs; i++) {

         char *name = av_asprintf("in%d", i);

         AVFilterPad pad = {
             .name             = name,
             .type             = AVMEDIA_TYPE_AUDIO,

             .filter_frame     = filter_frame,

         };

         if (!name)
             return AVERROR(ENOMEM);

         if ((ret = ff_insert_inpad(ctx, i, &pad)) < 0) {
             av_freep(&pad.name);
             return ret;
         }

     }
     return 0;
 }
 

 static const AVFilterPad amerge_outputs[] = {
     {
         .name          = "default",
         .type          = AVMEDIA_TYPE_AUDIO,
         .config_props  = config_output,
         .request_frame = request_frame,
     },
     { NULL }
 };
 

 AVFilter ff_af_amerge = {

     .name          = "amerge",

     .description   = NULL_IF_CONFIG_SMALL("Merge two or more audio streams into "

                                           "a single multi-channel stream."),
     .priv_size     = sizeof(AMergeContext),

     .init          = init,

     .uninit        = uninit,
     .query_formats = query_formats,

     .inputs        = NULL,
     .outputs       = amerge_outputs,
     .priv_class    = &amerge_class,

     .flags         = AVFILTER_FLAG_DYNAMIC_INPUTS,

 };