/*
  *
  * This file is part of Libav.
  *
  * Libav 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.
  *
  * Libav 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 Libav; if not, write to the Free Software
  * Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA
  */
 
 /**
  * @file
  * Audio join filter
  *
  * Join multiple audio inputs as different channels in
  * a single output
  */
 
 #include "libavutil/avassert.h"

 #include "libavutil/channel_layout.h"

 #include "libavutil/common.h"

 #include "libavutil/opt.h"
 
 #include "audio.h"
 #include "avfilter.h"
 #include "formats.h"
 #include "internal.h"
 
 typedef struct ChannelMap {
     int input;                ///< input stream index
     int       in_channel_idx; ///< index of in_channel in the input stream data
     uint64_t  in_channel;     ///< layout describing the input channel
     uint64_t out_channel;     ///< layout describing the output channel
 } ChannelMap;
 
 typedef struct JoinContext {
     const AVClass *class;
 
     int inputs;
     char *map;
     char    *channel_layout_str;
     uint64_t channel_layout;
 
     int      nb_channels;
     ChannelMap *channels;
 
     /**
      * Temporary storage for input frames, until we get one on each input.
      */
     AVFilterBufferRef **input_frames;
 
     /**
      *  Temporary storage for data pointers, for assembling the output buffer.
      */
     uint8_t **data;
 } JoinContext;
 
 /**
  * To avoid copying the data from input buffers, this filter creates
  * a custom output buffer that stores references to all inputs and
  * unrefs them on free.
  */
 typedef struct JoinBufferPriv {
     AVFilterBufferRef **in_buffers;
     int              nb_in_buffers;
 } JoinBufferPriv;
 
 #define OFFSET(x) offsetof(JoinContext, x)
 #define A AV_OPT_FLAG_AUDIO_PARAM

 #define F AV_OPT_FLAG_FILTERING_PARAM

 static const AVOption join_options[] = {

     { "inputs",         "Number of input streams.", OFFSET(inputs),             AV_OPT_TYPE_INT,    { .i64 = 2 }, 1, INT_MAX,       A|F },

     { "channel_layout", "Channel layout of the "

                         "output stream.",           OFFSET(channel_layout_str), AV_OPT_TYPE_STRING, {.str = "stereo"}, 0, 0, A|F },

     { "map",            "A comma-separated list of channels maps in the format "
                         "'input_stream.input_channel-output_channel.",

                                                     OFFSET(map),                AV_OPT_TYPE_STRING,                 .flags = A|F },

     { NULL },
 };
 
 static const AVClass join_class = {
     .class_name = "join filter",
     .item_name  = av_default_item_name,
     .option     = join_options,
     .version    = LIBAVUTIL_VERSION_INT,
 };
 

 static int filter_frame(AVFilterLink *link, AVFilterBufferRef *buf)

 {
     AVFilterContext *ctx = link->dst;
     JoinContext       *s = ctx->priv;
     int i;
 
     for (i = 0; i < ctx->nb_inputs; i++)
         if (link == ctx->inputs[i])
             break;
     av_assert0(i < ctx->nb_inputs);
     av_assert0(!s->input_frames[i]);
     s->input_frames[i] = buf;

 
     return 0;

 }
 
 static int parse_maps(AVFilterContext *ctx)
 {
     JoinContext *s = ctx->priv;
     char *cur      = s->map;
 
     while (cur && *cur) {
         char *sep, *next, *p;
         uint64_t in_channel = 0, out_channel = 0;
         int input_idx, out_ch_idx, in_ch_idx;
 
         next = strchr(cur, ',');
         if (next)
             *next++ = 0;
 
         /* split the map into input and output parts */
         if (!(sep = strchr(cur, '-'))) {
             av_log(ctx, AV_LOG_ERROR, "Missing separator '-' in channel "
                    "map '%s'\n", cur);
             return AVERROR(EINVAL);
         }
         *sep++ = 0;
 
 #define PARSE_CHANNEL(str, var, inout)                                         \
         if (!(var = av_get_channel_layout(str))) {                             \
             av_log(ctx, AV_LOG_ERROR, "Invalid " inout " channel: %s.\n", str);\
             return AVERROR(EINVAL);                                            \
         }                                                                      \
         if (av_get_channel_layout_nb_channels(var) != 1) {                     \
             av_log(ctx, AV_LOG_ERROR, "Channel map describes more than one "   \
                    inout " channel.\n");                                       \
             return AVERROR(EINVAL);                                            \
         }
 
         /* parse output channel */
         PARSE_CHANNEL(sep, out_channel, "output");
         if (!(out_channel & s->channel_layout)) {
             av_log(ctx, AV_LOG_ERROR, "Output channel '%s' is not present in "
                    "requested channel layout.\n", sep);
             return AVERROR(EINVAL);
         }
 
         out_ch_idx = av_get_channel_layout_channel_index(s->channel_layout,
                                                          out_channel);
         if (s->channels[out_ch_idx].input >= 0) {
             av_log(ctx, AV_LOG_ERROR, "Multiple maps for output channel "
                    "'%s'.\n", sep);
             return AVERROR(EINVAL);
         }
 
         /* parse input channel */
         input_idx = strtol(cur, &cur, 0);
         if (input_idx < 0 || input_idx >= s->inputs) {
             av_log(ctx, AV_LOG_ERROR, "Invalid input stream index: %d.\n",
                    input_idx);
             return AVERROR(EINVAL);
         }
 
         if (*cur)
             cur++;
 
         in_ch_idx = strtol(cur, &p, 0);
         if (p == cur) {
             /* channel specifier is not a number,
              * try to parse as channel name */
             PARSE_CHANNEL(cur, in_channel, "input");
         }
 
         s->channels[out_ch_idx].input      = input_idx;
         if (in_channel)
             s->channels[out_ch_idx].in_channel = in_channel;
         else
             s->channels[out_ch_idx].in_channel_idx = in_ch_idx;
 
         cur = next;
     }
     return 0;
 }
 

 static int join_init(AVFilterContext *ctx, const char *args)

 {
     JoinContext *s = ctx->priv;
     int ret, i;
 
     s->class = &join_class;
     av_opt_set_defaults(s);

     if ((ret = av_set_options_string(s, args, "=", ":")) < 0)

         return ret;
 
     if (!(s->channel_layout = av_get_channel_layout(s->channel_layout_str))) {
         av_log(ctx, AV_LOG_ERROR, "Error parsing channel layout '%s'.\n",
                s->channel_layout_str);
         ret = AVERROR(EINVAL);
         goto fail;
     }
 
     s->nb_channels  = av_get_channel_layout_nb_channels(s->channel_layout);
     s->channels     = av_mallocz(sizeof(*s->channels) * s->nb_channels);
     s->data         = av_mallocz(sizeof(*s->data)     * s->nb_channels);
     s->input_frames = av_mallocz(sizeof(*s->input_frames) * s->inputs);
     if (!s->channels || !s->data || !s->input_frames) {
         ret = AVERROR(ENOMEM);
         goto fail;
     }
 
     for (i = 0; i < s->nb_channels; i++) {
         s->channels[i].out_channel = av_channel_layout_extract_channel(s->channel_layout, i);
         s->channels[i].input       = -1;
     }
 
     if ((ret = parse_maps(ctx)) < 0)
         goto fail;
 
     for (i = 0; i < s->inputs; i++) {
         char name[32];
         AVFilterPad pad = { 0 };
 
         snprintf(name, sizeof(name), "input%d", i);
         pad.type           = AVMEDIA_TYPE_AUDIO;
         pad.name           = av_strdup(name);

         pad.filter_frame   = filter_frame;

 
         pad.needs_fifo = 1;
 
         ff_insert_inpad(ctx, i, &pad);
     }
 
 fail:
     av_opt_free(s);
     return ret;
 }
 
 static void join_uninit(AVFilterContext *ctx)
 {
     JoinContext *s = ctx->priv;
     int i;
 
     for (i = 0; i < ctx->nb_inputs; i++) {
         av_freep(&ctx->input_pads[i].name);

         avfilter_unref_bufferp(&s->input_frames[i]);

     }
 
     av_freep(&s->channels);
     av_freep(&s->data);
     av_freep(&s->input_frames);
 }
 
 static int join_query_formats(AVFilterContext *ctx)
 {
     JoinContext *s = ctx->priv;
     AVFilterChannelLayouts *layouts = NULL;
     int i;
 
     ff_add_channel_layout(&layouts, s->channel_layout);
     ff_channel_layouts_ref(layouts, &ctx->outputs[0]->in_channel_layouts);
 
     for (i = 0; i < ctx->nb_inputs; i++)
         ff_channel_layouts_ref(ff_all_channel_layouts(),
                                &ctx->inputs[i]->out_channel_layouts);
 
     ff_set_common_formats    (ctx, ff_planar_sample_fmts());
     ff_set_common_samplerates(ctx, ff_all_samplerates());
 
     return 0;
 }
 
 static void guess_map_matching(AVFilterContext *ctx, ChannelMap *ch,
                                uint64_t *inputs)
 {
     int i;
 
     for (i = 0; i < ctx->nb_inputs; i++) {
         AVFilterLink *link = ctx->inputs[i];
 
         if (ch->out_channel & link->channel_layout &&
             !(ch->out_channel & inputs[i])) {
             ch->input      = i;
             ch->in_channel = ch->out_channel;
             inputs[i]     |= ch->out_channel;
             return;
         }
     }
 }
 
 static void guess_map_any(AVFilterContext *ctx, ChannelMap *ch,
                           uint64_t *inputs)
 {
     int i;
 
     for (i = 0; i < ctx->nb_inputs; i++) {
         AVFilterLink *link = ctx->inputs[i];
 
         if ((inputs[i] & link->channel_layout) != link->channel_layout) {
             uint64_t unused = link->channel_layout & ~inputs[i];
 
             ch->input      = i;
             ch->in_channel = av_channel_layout_extract_channel(unused, 0);
             inputs[i]     |= ch->in_channel;
             return;
         }
     }
 }
 
 static int join_config_output(AVFilterLink *outlink)
 {
     AVFilterContext *ctx = outlink->src;
     JoinContext       *s = ctx->priv;
     uint64_t *inputs;   // nth element tracks which channels are used from nth input
     int i, ret = 0;
 
     /* initialize inputs to user-specified mappings */
     if (!(inputs = av_mallocz(sizeof(*inputs) * ctx->nb_inputs)))
         return AVERROR(ENOMEM);
     for (i = 0; i < s->nb_channels; i++) {
         ChannelMap *ch = &s->channels[i];
         AVFilterLink *inlink;
 
         if (ch->input < 0)
             continue;
 
         inlink = ctx->inputs[ch->input];
 
         if (!ch->in_channel)
             ch->in_channel = av_channel_layout_extract_channel(inlink->channel_layout,
                                                                ch->in_channel_idx);
 
         if (!(ch->in_channel & inlink->channel_layout)) {
             av_log(ctx, AV_LOG_ERROR, "Requested channel %s is not present in "
                    "input stream #%d.\n", av_get_channel_name(ch->in_channel),
                    ch->input);
             ret = AVERROR(EINVAL);
             goto fail;
         }
 
         inputs[ch->input] |= ch->in_channel;
     }
 
     /* guess channel maps when not explicitly defined */
     /* first try unused matching channels */
     for (i = 0; i < s->nb_channels; i++) {
         ChannelMap *ch = &s->channels[i];
 
         if (ch->input < 0)
             guess_map_matching(ctx, ch, inputs);
     }
 
     /* if the above failed, try to find _any_ unused input channel */
     for (i = 0; i < s->nb_channels; i++) {
         ChannelMap *ch = &s->channels[i];
 
         if (ch->input < 0)
             guess_map_any(ctx, ch, inputs);
 
         if (ch->input < 0) {
             av_log(ctx, AV_LOG_ERROR, "Could not find input channel for "
                    "output channel '%s'.\n",
                    av_get_channel_name(ch->out_channel));
             goto fail;
         }
 
         ch->in_channel_idx = av_get_channel_layout_channel_index(ctx->inputs[ch->input]->channel_layout,
                                                                  ch->in_channel);
     }
 
     /* print mappings */
     av_log(ctx, AV_LOG_VERBOSE, "mappings: ");
     for (i = 0; i < s->nb_channels; i++) {
         ChannelMap *ch = &s->channels[i];
         av_log(ctx, AV_LOG_VERBOSE, "%d.%s => %s ", ch->input,
                av_get_channel_name(ch->in_channel),
                av_get_channel_name(ch->out_channel));
     }
     av_log(ctx, AV_LOG_VERBOSE, "\n");
 
     for (i = 0; i < ctx->nb_inputs; i++) {
         if (!inputs[i])
             av_log(ctx, AV_LOG_WARNING, "No channels are used from input "
                    "stream %d.\n", i);
     }
 
 fail:
     av_freep(&inputs);
     return ret;
 }
 
 static void join_free_buffer(AVFilterBuffer *buf)
 {
     JoinBufferPriv *priv = buf->priv;
 
     if (priv) {
         int i;
 
         for (i = 0; i < priv->nb_in_buffers; i++)

             avfilter_unref_bufferp(&priv->in_buffers[i]);

 
         av_freep(&priv->in_buffers);
         av_freep(&buf->priv);
     }
 
     if (buf->extended_data != buf->data)
         av_freep(&buf->extended_data);
     av_freep(&buf);
 }
 
 static int join_request_frame(AVFilterLink *outlink)
 {
     AVFilterContext *ctx = outlink->src;
     JoinContext *s       = ctx->priv;
     AVFilterBufferRef *buf;
     JoinBufferPriv *priv;
     int linesize   = INT_MAX;
     int perms      = ~0;

     int nb_samples = 0;

     int i, j, ret;
 
     /* get a frame on each input */
     for (i = 0; i < ctx->nb_inputs; i++) {
         AVFilterLink *inlink = ctx->inputs[i];
 
         if (!s->input_frames[i] &&
             (ret = ff_request_frame(inlink)) < 0)
             return ret;
 
         /* request the same number of samples on all inputs */
         if (i == 0) {
             nb_samples = s->input_frames[0]->audio->nb_samples;
 
             for (j = 1; !i && j < ctx->nb_inputs; j++)
                 ctx->inputs[j]->request_samples = nb_samples;
         }
     }
 
     for (i = 0; i < s->nb_channels; i++) {
         ChannelMap *ch = &s->channels[i];
         AVFilterBufferRef *cur_buf = s->input_frames[ch->input];
 
         s->data[i] = cur_buf->extended_data[ch->in_channel_idx];
         linesize   = FFMIN(linesize, cur_buf->linesize[0]);
         perms     &= cur_buf->perms;
     }
 

     av_assert0(nb_samples > 0);

     buf = avfilter_get_audio_buffer_ref_from_arrays(s->data, linesize, perms,
                                                     nb_samples, outlink->format,
                                                     outlink->channel_layout);
     if (!buf)
         return AVERROR(ENOMEM);
 
     buf->buf->free = join_free_buffer;
     buf->pts       = s->input_frames[0]->pts;
 
     if (!(priv = av_mallocz(sizeof(*priv))))
         goto fail;
     if (!(priv->in_buffers = av_mallocz(sizeof(*priv->in_buffers) * ctx->nb_inputs)))
         goto fail;
 
     for (i = 0; i < ctx->nb_inputs; i++)
         priv->in_buffers[i] = s->input_frames[i];
     priv->nb_in_buffers = ctx->nb_inputs;
     buf->buf->priv      = priv;
 

     ret = ff_filter_frame(outlink, buf);

 
     memset(s->input_frames, 0, sizeof(*s->input_frames) * ctx->nb_inputs);
 

     return ret;

 
 fail:
     avfilter_unref_buffer(buf);
     if (priv)
         av_freep(&priv->in_buffers);
     av_freep(&priv);
     return AVERROR(ENOMEM);
 }
 

 static const AVFilterPad avfilter_af_join_outputs[] = {
     {
         .name          = "default",
         .type          = AVMEDIA_TYPE_AUDIO,
         .config_props  = join_config_output,
         .request_frame = join_request_frame,
     },
     { NULL }
 };
 

 AVFilter avfilter_af_join = {
     .name           = "join",
     .description    = NULL_IF_CONFIG_SMALL("Join multiple audio streams into "
                                            "multi-channel output"),
     .priv_size      = sizeof(JoinContext),
 
     .init           = join_init,
     .uninit         = join_uninit,
     .query_formats  = join_query_formats,
 

     .inputs  = NULL,

     .outputs = avfilter_af_join_outputs,

     .priv_class = &join_class,

 };