/*

  * 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
  */
 

 #include <stdint.h>

 #include "config.h"
 
 #include "libavutil/avassert.h"
 #include "libavutil/channel_layout.h"
 #include "libavutil/common.h"
 #include "libavutil/log.h"
 #include "libavutil/mathematics.h"
 #include "libavutil/opt.h"
 #include "libavutil/samplefmt.h"
 
 #include "audio.h"
 #include "avfilter.h"
 #include "internal.h"
 
 typedef struct TrimContext {
     const AVClass *class;
 
     /*
      * AVOptions
      */

     int64_t duration;
     int64_t start_time, end_time;

     int64_t start_frame, end_frame;
     /*
      * in the link timebase for video,
      * in 1/samplerate for audio
      */
     int64_t start_pts, end_pts;
     int64_t start_sample, end_sample;
 
     /*
      * number of video frames that arrived on this filter so far
      */
     int64_t nb_frames;
     /*
      * number of audio samples that arrived on this filter so far
      */
     int64_t nb_samples;
     /*
      * timestamp of the first frame in the output, in the timebase units
      */
     int64_t first_pts;
     /*
      * duration in the timebase units
      */
     int64_t duration_tb;
 
     int64_t next_pts;
 
     int eof;
 } TrimContext;
 

 static av_cold int init(AVFilterContext *ctx)

 {
     TrimContext *s = ctx->priv;
 
     s->first_pts = AV_NOPTS_VALUE;
 
     return 0;
 }
 
 static int config_input(AVFilterLink *inlink)
 {
     AVFilterContext *ctx = inlink->dst;
     TrimContext       *s = ctx->priv;
     AVRational tb = (inlink->type == AVMEDIA_TYPE_VIDEO) ?
                      inlink->time_base : (AVRational){ 1, inlink->sample_rate };
 

     if (s->start_time != INT64_MAX) {
         int64_t start_pts = av_rescale_q(s->start_time, AV_TIME_BASE_Q, tb);

         if (s->start_pts == AV_NOPTS_VALUE || start_pts < s->start_pts)
             s->start_pts = start_pts;
     }

     if (s->end_time != INT64_MAX) {
         int64_t end_pts = av_rescale_q(s->end_time, AV_TIME_BASE_Q, tb);

         if (s->end_pts == AV_NOPTS_VALUE || end_pts > s->end_pts)
             s->end_pts = end_pts;
     }
     if (s->duration)

         s->duration_tb = av_rescale_q(s->duration, AV_TIME_BASE_Q, tb);

 
     return 0;
 }
 
 #define OFFSET(x) offsetof(TrimContext, x)
 #define COMMON_OPTS                                                                                                                                                         \

     { "start",       "Timestamp of the first frame that "                                                                                                        \
         "should be passed",                                              OFFSET(start_time),  AV_OPT_TYPE_DURATION, { .i64 = INT64_MAX },    INT64_MIN, INT64_MAX, FLAGS }, \

     { "starti",      "Timestamp of the first frame that "                                                                                                        \

         "should be passed",                                              OFFSET(start_time),  AV_OPT_TYPE_DURATION, { .i64 = INT64_MAX },    INT64_MIN, INT64_MAX, FLAGS }, \

     { "end",         "Timestamp of the first frame that "                                                                                                        \
         "should be dropped again",                                       OFFSET(end_time),    AV_OPT_TYPE_DURATION, { .i64 = INT64_MAX },    INT64_MIN, INT64_MAX, FLAGS }, \

     { "endi",        "Timestamp of the first frame that "                                                                                                        \

         "should be dropped again",                                       OFFSET(end_time),    AV_OPT_TYPE_DURATION, { .i64 = INT64_MAX },    INT64_MIN, INT64_MAX, FLAGS }, \

     { "start_pts",   "Timestamp of the first frame that should be "                                                                                                         \
        " passed",                                                        OFFSET(start_pts),   AV_OPT_TYPE_INT64,  { .i64 = AV_NOPTS_VALUE }, INT64_MIN, INT64_MAX, FLAGS }, \
     { "end_pts",     "Timestamp of the first frame that should be "                                                                                                         \
         "dropped again",                                                 OFFSET(end_pts),     AV_OPT_TYPE_INT64,  { .i64 = AV_NOPTS_VALUE }, INT64_MIN, INT64_MAX, FLAGS }, \

     { "duration",    "Maximum duration of the output",                   OFFSET(duration),    AV_OPT_TYPE_DURATION, { .i64 = 0 },                    0, INT64_MAX, FLAGS }, \

     { "durationi",   "Maximum duration of the output",                   OFFSET(duration),    AV_OPT_TYPE_DURATION, { .i64 = 0 },                    0, INT64_MAX, FLAGS },
 

 
 #if CONFIG_TRIM_FILTER
 static int trim_filter_frame(AVFilterLink *inlink, AVFrame *frame)
 {
     AVFilterContext *ctx = inlink->dst;
     TrimContext       *s = ctx->priv;
     int drop;
 
     /* drop everything if EOF has already been returned */
     if (s->eof) {
         av_frame_free(&frame);
         return 0;
     }
 
     if (s->start_frame >= 0 || s->start_pts != AV_NOPTS_VALUE) {
         drop = 1;
         if (s->start_frame >= 0 && s->nb_frames >= s->start_frame)
             drop = 0;
         if (s->start_pts != AV_NOPTS_VALUE && frame->pts != AV_NOPTS_VALUE &&
             frame->pts >= s->start_pts)
             drop = 0;
         if (drop)
             goto drop;
     }
 
     if (s->first_pts == AV_NOPTS_VALUE && frame->pts != AV_NOPTS_VALUE)
         s->first_pts = frame->pts;
 
     if (s->end_frame != INT64_MAX || s->end_pts != AV_NOPTS_VALUE || s->duration_tb) {
         drop = 1;
 
         if (s->end_frame != INT64_MAX && s->nb_frames < s->end_frame)
             drop = 0;
         if (s->end_pts != AV_NOPTS_VALUE && frame->pts != AV_NOPTS_VALUE &&
             frame->pts < s->end_pts)
             drop = 0;
         if (s->duration_tb && frame->pts != AV_NOPTS_VALUE &&
             frame->pts - s->first_pts < s->duration_tb)
             drop = 0;
 
         if (drop) {

             s->eof = 1;
             ff_avfilter_link_set_out_status(inlink, AVERROR_EOF, AV_NOPTS_VALUE);

             goto drop;
         }
     }
 
     s->nb_frames++;
 
     return ff_filter_frame(ctx->outputs[0], frame);
 
 drop:
     s->nb_frames++;
     av_frame_free(&frame);
     return 0;
 }
 

 #define FLAGS AV_OPT_FLAG_VIDEO_PARAM | AV_OPT_FLAG_FILTERING_PARAM

 static const AVOption trim_options[] = {
     COMMON_OPTS
     { "start_frame", "Number of the first frame that should be passed "
         "to the output",                                                 OFFSET(start_frame), AV_OPT_TYPE_INT64,  { .i64 = -1 },       -1, INT64_MAX, FLAGS },
     { "end_frame",   "Number of the first frame that should be dropped "
         "again",                                                         OFFSET(end_frame),   AV_OPT_TYPE_INT64,  { .i64 = INT64_MAX }, 0, INT64_MAX, FLAGS },

     { NULL }

 };
 #undef FLAGS
 

 AVFILTER_DEFINE_CLASS(trim);

 
 static const AVFilterPad trim_inputs[] = {
     {
         .name         = "default",
         .type         = AVMEDIA_TYPE_VIDEO,
         .filter_frame = trim_filter_frame,
         .config_props = config_input,
     },
     { NULL }
 };
 
 static const AVFilterPad trim_outputs[] = {
     {

         .name         = "default",
         .type         = AVMEDIA_TYPE_VIDEO,

     },
     { NULL }
 };
 

 AVFilter ff_vf_trim = {

     .name        = "trim",
     .description = NULL_IF_CONFIG_SMALL("Pick one continuous section from the input, drop the rest."),
     .init        = init,
     .priv_size   = sizeof(TrimContext),
     .priv_class  = &trim_class,
     .inputs      = trim_inputs,
     .outputs     = trim_outputs,
 };
 #endif // CONFIG_TRIM_FILTER
 
 #if CONFIG_ATRIM_FILTER
 static int atrim_filter_frame(AVFilterLink *inlink, AVFrame *frame)
 {
     AVFilterContext *ctx = inlink->dst;
     TrimContext       *s = ctx->priv;

     int64_t start_sample, end_sample;

     int64_t pts;
     int drop;
 
     /* drop everything if EOF has already been returned */
     if (s->eof) {
         av_frame_free(&frame);
         return 0;
     }
 
     if (frame->pts != AV_NOPTS_VALUE)
         pts = av_rescale_q(frame->pts, inlink->time_base,
                            (AVRational){ 1, inlink->sample_rate });
     else
         pts = s->next_pts;
     s->next_pts = pts + frame->nb_samples;
 
     /* check if at least a part of the frame is after the start time */
     if (s->start_sample < 0 && s->start_pts == AV_NOPTS_VALUE) {
         start_sample = 0;
     } else {
         drop = 1;
         start_sample = frame->nb_samples;
 
         if (s->start_sample >= 0 &&
             s->nb_samples + frame->nb_samples > s->start_sample) {
             drop         = 0;
             start_sample = FFMIN(start_sample, s->start_sample - s->nb_samples);
         }
 
         if (s->start_pts != AV_NOPTS_VALUE && pts != AV_NOPTS_VALUE &&
             pts + frame->nb_samples > s->start_pts) {
             drop = 0;
             start_sample = FFMIN(start_sample, s->start_pts - pts);
         }
 
         if (drop)
             goto drop;
     }
 
     if (s->first_pts == AV_NOPTS_VALUE)
         s->first_pts = pts + start_sample;
 
     /* check if at least a part of the frame is before the end time */
     if (s->end_sample == INT64_MAX && s->end_pts == AV_NOPTS_VALUE && !s->duration_tb) {
         end_sample = frame->nb_samples;
     } else {
         drop       = 1;
         end_sample = 0;
 
         if (s->end_sample != INT64_MAX &&
             s->nb_samples < s->end_sample) {
             drop       = 0;
             end_sample = FFMAX(end_sample, s->end_sample - s->nb_samples);
         }
 
         if (s->end_pts != AV_NOPTS_VALUE && pts != AV_NOPTS_VALUE &&
             pts < s->end_pts) {
             drop       = 0;
             end_sample = FFMAX(end_sample, s->end_pts - pts);
         }
 
         if (s->duration_tb && pts - s->first_pts < s->duration_tb) {
             drop       = 0;
             end_sample = FFMAX(end_sample, s->first_pts + s->duration_tb - pts);
         }
 
         if (drop) {

             s->eof = 1;
             ff_avfilter_link_set_out_status(inlink, AVERROR_EOF, AV_NOPTS_VALUE);

             goto drop;
         }
     }
 
     s->nb_samples += frame->nb_samples;
     start_sample   = FFMAX(0, start_sample);
     end_sample     = FFMIN(frame->nb_samples, end_sample);

     av_assert0(start_sample < end_sample || (start_sample == end_sample && !frame->nb_samples));

 
     if (start_sample) {
         AVFrame *out = ff_get_audio_buffer(ctx->outputs[0], end_sample - start_sample);
         if (!out) {
             av_frame_free(&frame);
             return AVERROR(ENOMEM);
         }
 
         av_frame_copy_props(out, frame);
         av_samples_copy(out->extended_data, frame->extended_data, 0, start_sample,

                         out->nb_samples, inlink->channels,

                         frame->format);
         if (out->pts != AV_NOPTS_VALUE)
             out->pts += av_rescale_q(start_sample, (AVRational){ 1, out->sample_rate },
                                      inlink->time_base);
 
         av_frame_free(&frame);
         frame = out;
     } else
         frame->nb_samples = end_sample;
 
     return ff_filter_frame(ctx->outputs[0], frame);
 
 drop:
     s->nb_samples += frame->nb_samples;
     av_frame_free(&frame);
     return 0;
 }
 

 #define FLAGS AV_OPT_FLAG_AUDIO_PARAM | AV_OPT_FLAG_FILTERING_PARAM

 static const AVOption atrim_options[] = {
     COMMON_OPTS
     { "start_sample", "Number of the first audio sample that should be "
         "passed to the output",                                          OFFSET(start_sample), AV_OPT_TYPE_INT64,  { .i64 = -1 },       -1, INT64_MAX, FLAGS },
     { "end_sample",   "Number of the first audio sample that should be "
         "dropped again",                                                 OFFSET(end_sample),   AV_OPT_TYPE_INT64,  { .i64 = INT64_MAX }, 0, INT64_MAX, FLAGS },

     { NULL }

 };
 #undef FLAGS
 

 AVFILTER_DEFINE_CLASS(atrim);

 
 static const AVFilterPad atrim_inputs[] = {
     {
         .name         = "default",
         .type         = AVMEDIA_TYPE_AUDIO,
         .filter_frame = atrim_filter_frame,
         .config_props = config_input,
     },
     { NULL }
 };
 
 static const AVFilterPad atrim_outputs[] = {
     {

         .name         = "default",
         .type         = AVMEDIA_TYPE_AUDIO,

     },
     { NULL }
 };
 

 AVFilter ff_af_atrim = {

     .name        = "atrim",
     .description = NULL_IF_CONFIG_SMALL("Pick one continuous section from the input, drop the rest."),
     .init        = init,
     .priv_size   = sizeof(TrimContext),
     .priv_class  = &atrim_class,
     .inputs      = atrim_inputs,
     .outputs     = atrim_outputs,
 };
 #endif // CONFIG_ATRIM_FILTER