/*
  * Copyright (c) 2012 Nicolas George
  *
  * 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
  * concat audio-video filter
  */
 
 #include "libavutil/avassert.h"

 #include "libavutil/avstring.h"

 #include "libavutil/channel_layout.h"

 #include "libavutil/opt.h"
 #include "avfilter.h"
 #define FF_BUFQUEUE_SIZE 256
 #include "bufferqueue.h"
 #include "internal.h"
 #include "video.h"
 #include "audio.h"
 
 #define TYPE_ALL 2
 

 typedef struct ConcatContext {

     const AVClass *class;
     unsigned nb_streams[TYPE_ALL]; /**< number of out streams of each type */
     unsigned nb_segments;
     unsigned cur_idx; /**< index of the first input of current segment */
     int64_t delta_ts; /**< timestamp to add to produce output timestamps */
     unsigned nb_in_active; /**< number of active inputs in current segment */

     unsigned unsafe;

     struct concat_in {
         int64_t pts;
         int64_t nb_frames;
         unsigned eof;
         struct FFBufQueue queue;
     } *in;
 } ConcatContext;
 
 #define OFFSET(x) offsetof(ConcatContext, x)

 #define A AV_OPT_FLAG_AUDIO_PARAM
 #define F AV_OPT_FLAG_FILTERING_PARAM
 #define V AV_OPT_FLAG_VIDEO_PARAM

 
 static const AVOption concat_options[] = {
     { "n", "specify the number of segments", OFFSET(nb_segments),

       AV_OPT_TYPE_INT, { .i64 = 2 }, 1, INT_MAX, V|A|F},

     { "v", "specify the number of video streams",
       OFFSET(nb_streams[AVMEDIA_TYPE_VIDEO]),

       AV_OPT_TYPE_INT, { .i64 = 1 }, 0, INT_MAX, V|F },

     { "a", "specify the number of audio streams",
       OFFSET(nb_streams[AVMEDIA_TYPE_AUDIO]),

       AV_OPT_TYPE_INT, { .i64 = 0 }, 0, INT_MAX, A|F},

     { "unsafe", "enable unsafe mode",
       OFFSET(unsafe),

       AV_OPT_TYPE_BOOL, { .i64 = 0 }, 0, 1, V|A|F},

     { NULL }

 };
 
 AVFILTER_DEFINE_CLASS(concat);
 
 static int query_formats(AVFilterContext *ctx)
 {
     ConcatContext *cat = ctx->priv;
     unsigned type, nb_str, idx0 = 0, idx, str, seg;

     AVFilterFormats *formats, *rates = NULL;
     AVFilterChannelLayouts *layouts = NULL;

     int ret;

 
     for (type = 0; type < TYPE_ALL; type++) {
         nb_str = cat->nb_streams[type];
         for (str = 0; str < nb_str; str++) {
             idx = idx0;
 
             /* Set the output formats */
             formats = ff_all_formats(type);

             if ((ret = ff_formats_ref(formats, &ctx->outputs[idx]->in_formats)) < 0)
                 return ret;
 

             if (type == AVMEDIA_TYPE_AUDIO) {
                 rates = ff_all_samplerates();

                 if ((ret = ff_formats_ref(rates, &ctx->outputs[idx]->in_samplerates)) < 0)
                     return ret;

                 layouts = ff_all_channel_layouts();

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

             }
 
             /* Set the same formats for each corresponding input */
             for (seg = 0; seg < cat->nb_segments; seg++) {

                 if ((ret = ff_formats_ref(formats, &ctx->inputs[idx]->out_formats)) < 0)
                     return ret;

                 if (type == AVMEDIA_TYPE_AUDIO) {

                     if ((ret = ff_formats_ref(rates, &ctx->inputs[idx]->out_samplerates)) < 0 ||
                         (ret = ff_channel_layouts_ref(layouts, &ctx->inputs[idx]->out_channel_layouts)) < 0)
                         return ret;

                 }
                 idx += ctx->nb_outputs;
             }
 
             idx0++;
         }
     }
     return 0;
 }
 
 static int config_output(AVFilterLink *outlink)
 {
     AVFilterContext *ctx = outlink->src;
     ConcatContext *cat   = ctx->priv;
     unsigned out_no = FF_OUTLINK_IDX(outlink);
     unsigned in_no  = out_no, seg;
     AVFilterLink *inlink = ctx->inputs[in_no];
 
     /* enhancement: find a common one */
     outlink->time_base           = AV_TIME_BASE_Q;
     outlink->w                   = inlink->w;
     outlink->h                   = inlink->h;
     outlink->sample_aspect_ratio = inlink->sample_aspect_ratio;
     outlink->format              = inlink->format;
     for (seg = 1; seg < cat->nb_segments; seg++) {
         inlink = ctx->inputs[in_no += ctx->nb_outputs];

         if (!outlink->sample_aspect_ratio.num)
             outlink->sample_aspect_ratio = inlink->sample_aspect_ratio;

         /* possible enhancement: unsafe mode, do not check */
         if (outlink->w                       != inlink->w                       ||
             outlink->h                       != inlink->h                       ||

             outlink->sample_aspect_ratio.num != inlink->sample_aspect_ratio.num &&
                                                 inlink->sample_aspect_ratio.num ||

             outlink->sample_aspect_ratio.den != inlink->sample_aspect_ratio.den) {
             av_log(ctx, AV_LOG_ERROR, "Input link %s parameters "
                    "(size %dx%d, SAR %d:%d) do not match the corresponding "
                    "output link %s parameters (%dx%d, SAR %d:%d)\n",
                    ctx->input_pads[in_no].name, inlink->w, inlink->h,
                    inlink->sample_aspect_ratio.num,
                    inlink->sample_aspect_ratio.den,
                    ctx->input_pads[out_no].name, outlink->w, outlink->h,
                    outlink->sample_aspect_ratio.num,
                    outlink->sample_aspect_ratio.den);

             if (!cat->unsafe)
                 return AVERROR(EINVAL);

         }
     }
 
     return 0;
 }
 

 static int push_frame(AVFilterContext *ctx, unsigned in_no, AVFrame *buf)

 {
     ConcatContext *cat = ctx->priv;
     unsigned out_no = in_no % ctx->nb_outputs;
     AVFilterLink * inlink = ctx-> inputs[ in_no];
     AVFilterLink *outlink = ctx->outputs[out_no];
     struct concat_in *in = &cat->in[in_no];
 
     buf->pts = av_rescale_q(buf->pts, inlink->time_base, outlink->time_base);
     in->pts = buf->pts;
     in->nb_frames++;
     /* add duration to input PTS */
     if (inlink->sample_rate)
         /* use number of audio samples */

         in->pts += av_rescale_q(buf->nb_samples,

                                 av_make_q(1, inlink->sample_rate),

                                 outlink->time_base);
     else if (in->nb_frames >= 2)
         /* use mean duration */
         in->pts = av_rescale(in->pts, in->nb_frames, in->nb_frames - 1);
 
     buf->pts += cat->delta_ts;

     return ff_filter_frame(outlink, buf);

 }
 

 static int process_frame(AVFilterLink *inlink, AVFrame *buf)

 {
     AVFilterContext *ctx  = inlink->dst;
     ConcatContext *cat    = ctx->priv;
     unsigned in_no = FF_INLINK_IDX(inlink);
 
     if (in_no < cat->cur_idx) {
         av_log(ctx, AV_LOG_ERROR, "Frame after EOF on input %s\n",
                ctx->input_pads[in_no].name);

         av_frame_free(&buf);

     } else if (in_no >= cat->cur_idx + ctx->nb_outputs) {

         ff_bufqueue_add(ctx, &cat->in[in_no].queue, buf);
     } else {

         return push_frame(ctx, in_no, buf);

     }

     return 0;

 }
 

 static AVFrame *get_video_buffer(AVFilterLink *inlink, int w, int h)

 {
     AVFilterContext *ctx = inlink->dst;
     unsigned in_no = FF_INLINK_IDX(inlink);
     AVFilterLink *outlink = ctx->outputs[in_no % ctx->nb_outputs];
 

     return ff_get_video_buffer(outlink, w, h);

 }
 

 static AVFrame *get_audio_buffer(AVFilterLink *inlink, int nb_samples)

 {
     AVFilterContext *ctx = inlink->dst;
     unsigned in_no = FF_INLINK_IDX(inlink);
     AVFilterLink *outlink = ctx->outputs[in_no % ctx->nb_outputs];
 

     return ff_get_audio_buffer(outlink, nb_samples);

 }
 

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

 {

     return process_frame(inlink, buf);

 }
 
 static void close_input(AVFilterContext *ctx, unsigned in_no)
 {
     ConcatContext *cat = ctx->priv;
 
     cat->in[in_no].eof = 1;
     cat->nb_in_active--;
     av_log(ctx, AV_LOG_VERBOSE, "EOF on %s, %d streams left in segment.\n",
            ctx->input_pads[in_no].name, cat->nb_in_active);
 }
 

 static void find_next_delta_ts(AVFilterContext *ctx, int64_t *seg_delta)

 {
     ConcatContext *cat = ctx->priv;
     unsigned i = cat->cur_idx;
     unsigned imax = i + ctx->nb_outputs;
     int64_t pts;
 
     pts = cat->in[i++].pts;
     for (; i < imax; i++)
         pts = FFMAX(pts, cat->in[i].pts);
     cat->delta_ts += pts;

     *seg_delta = pts;

 }
 

 static int send_silence(AVFilterContext *ctx, unsigned in_no, unsigned out_no,
                         int64_t seg_delta)

 {
     ConcatContext *cat = ctx->priv;
     AVFilterLink *outlink = ctx->outputs[out_no];

     int64_t base_pts = cat->in[in_no].pts + cat->delta_ts - seg_delta;

     int64_t nb_samples, sent = 0;

     int frame_nb_samples, ret;

     AVRational rate_tb = { 1, ctx->inputs[in_no]->sample_rate };

     AVFrame *buf;

 
     if (!rate_tb.den)

         return AVERROR_BUG;

     nb_samples = av_rescale_q(seg_delta - cat->in[in_no].pts,

                               outlink->time_base, rate_tb);
     frame_nb_samples = FFMAX(9600, rate_tb.den / 5); /* arbitrary */
     while (nb_samples) {
         frame_nb_samples = FFMIN(frame_nb_samples, nb_samples);

         buf = ff_get_audio_buffer(outlink, frame_nb_samples);

         if (!buf)

             return AVERROR(ENOMEM);

         av_samples_set_silence(buf->extended_data, 0, frame_nb_samples,

                                outlink->channels, outlink->format);

         buf->pts = base_pts + av_rescale_q(sent, rate_tb, outlink->time_base);

         ret = ff_filter_frame(outlink, buf);
         if (ret < 0)
             return ret;

         sent       += frame_nb_samples;
         nb_samples -= frame_nb_samples;
     }

     return 0;

 }
 

 static int flush_segment(AVFilterContext *ctx)

 {

     int ret;

     ConcatContext *cat = ctx->priv;
     unsigned str, str_max;

     int64_t seg_delta;

     find_next_delta_ts(ctx, &seg_delta);

     cat->cur_idx += ctx->nb_outputs;
     cat->nb_in_active = ctx->nb_outputs;
     av_log(ctx, AV_LOG_VERBOSE, "Segment finished at pts=%"PRId64"\n",
            cat->delta_ts);
 
     if (cat->cur_idx < ctx->nb_inputs) {
         /* pad audio streams with silence */
         str = cat->nb_streams[AVMEDIA_TYPE_VIDEO];
         str_max = str + cat->nb_streams[AVMEDIA_TYPE_AUDIO];

         for (; str < str_max; str++) {

             ret = send_silence(ctx, cat->cur_idx - ctx->nb_outputs + str, str,
                                seg_delta);

             if (ret < 0)
                 return ret;
         }

         /* flush queued buffers */
         /* possible enhancement: flush in PTS order */
         str_max = cat->cur_idx + ctx->nb_outputs;

         for (str = cat->cur_idx; str < str_max; str++) {
             while (cat->in[str].queue.available) {
                 ret = push_frame(ctx, str, ff_bufqueue_get(&cat->in[str].queue));
                 if (ret < 0)
                     return ret;
             }
         }

     }

     return 0;

 }
 
 static int request_frame(AVFilterLink *outlink)
 {
     AVFilterContext *ctx = outlink->src;
     ConcatContext *cat   = ctx->priv;
     unsigned out_no = FF_OUTLINK_IDX(outlink);
     unsigned in_no  = out_no + cat->cur_idx;
     unsigned str, str_max;
     int ret;
 
     while (1) {
         if (in_no >= ctx->nb_inputs)
             return AVERROR_EOF;
         if (!cat->in[in_no].eof) {
             ret = ff_request_frame(ctx->inputs[in_no]);
             if (ret != AVERROR_EOF)
                 return ret;
             close_input(ctx, in_no);
         }
         /* cycle on all inputs to finish the segment */
         /* possible enhancement: request in PTS order */
         str_max = cat->cur_idx + ctx->nb_outputs - 1;
         for (str = cat->cur_idx; cat->nb_in_active;
              str = str == str_max ? cat->cur_idx : str + 1) {
             if (cat->in[str].eof)
                 continue;
             ret = ff_request_frame(ctx->inputs[str]);

             if (ret != AVERROR_EOF)

                 return ret;

             close_input(ctx, str);

         }

         ret = flush_segment(ctx);
         if (ret < 0)
             return ret;

         in_no += ctx->nb_outputs;
     }
 }
 

 static av_cold int init(AVFilterContext *ctx)

 {
     ConcatContext *cat = ctx->priv;
     unsigned seg, type, str;

     int ret;

 
     /* create input pads */
     for (seg = 0; seg < cat->nb_segments; seg++) {
         for (type = 0; type < TYPE_ALL; type++) {
             for (str = 0; str < cat->nb_streams[type]; str++) {
                 AVFilterPad pad = {
                     .type             = type,
                     .get_video_buffer = get_video_buffer,
                     .get_audio_buffer = get_audio_buffer,

                     .filter_frame     = filter_frame,

                 };

                 pad.name = av_asprintf("in%d:%c%d", seg, "va"[type], str);

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

             }
         }
     }
     /* create output pads */
     for (type = 0; type < TYPE_ALL; type++) {
         for (str = 0; str < cat->nb_streams[type]; str++) {
             AVFilterPad pad = {
                 .type          = type,
                 .config_props  = config_output,
                 .request_frame = request_frame,
             };

             pad.name = av_asprintf("out:%c%d", "va"[type], str);

             if ((ret = ff_insert_outpad(ctx, ctx->nb_outputs, &pad)) < 0) {
                 av_freep(&pad.name);
                 return ret;
             }

         }
     }
 
     cat->in = av_calloc(ctx->nb_inputs, sizeof(*cat->in));
     if (!cat->in)
         return AVERROR(ENOMEM);
     cat->nb_in_active = ctx->nb_outputs;
     return 0;
 }
 
 static av_cold void uninit(AVFilterContext *ctx)
 {
     ConcatContext *cat = ctx->priv;
     unsigned i;
 
     for (i = 0; i < ctx->nb_inputs; i++) {
         av_freep(&ctx->input_pads[i].name);
         ff_bufqueue_discard_all(&cat->in[i].queue);
     }
     for (i = 0; i < ctx->nb_outputs; i++)
         av_freep(&ctx->output_pads[i].name);

     av_freep(&cat->in);

 }
 

 AVFilter ff_avf_concat = {

     .name          = "concat",
     .description   = NULL_IF_CONFIG_SMALL("Concatenate audio and video streams."),
     .init          = init,
     .uninit        = uninit,
     .query_formats = query_formats,
     .priv_size     = sizeof(ConcatContext),

     .inputs        = NULL,
     .outputs       = NULL,

     .priv_class    = &concat_class,

     .flags         = AVFILTER_FLAG_DYNAMIC_INPUTS | AVFILTER_FLAG_DYNAMIC_OUTPUTS,

 };