/*
  * Interface to libtwolame for mp2 encoding
  * Copyright (c) 2012 Paul B Mahol
  *
  * 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
  * Interface to libtwolame for mp2 encoding.
  */
 
 #include <twolame.h>
 

 #include "libavutil/common.h"

 #include "libavutil/opt.h"

 #include "avcodec.h"
 #include "internal.h"
 #include "mpegaudio.h"
 
 typedef struct TWOLAMEContext {

     AVClass *class;
     int mode;
     int psymodel;
     int energy;
     int error_protection;
     int copyright;
     int original;
     int verbosity;

 
     twolame_options *glopts;

     int64_t next_pts;

 } TWOLAMEContext;
 
 static av_cold int twolame_encode_close(AVCodecContext *avctx)
 {
     TWOLAMEContext *s = avctx->priv_data;
     twolame_close(&s->glopts);
     return 0;
 }
 
 static av_cold int twolame_encode_init(AVCodecContext *avctx)
 {
     TWOLAMEContext *s = avctx->priv_data;
     int ret;
 
     avctx->frame_size = TWOLAME_SAMPLES_PER_FRAME;

     avctx->initial_padding = 512 - 32 + 1;

 
     s->glopts = twolame_init();
     if (!s->glopts)
         return AVERROR(ENOMEM);
 

     twolame_set_verbosity(s->glopts, s->verbosity);

     twolame_set_mode(s->glopts, s->mode);
     twolame_set_psymodel(s->glopts, s->psymodel);
     twolame_set_energy_levels(s->glopts, s->energy);
     twolame_set_error_protection(s->glopts, s->error_protection);

     twolame_set_copyright(s->glopts, s->copyright);
     twolame_set_original(s->glopts, s->original);

 
     twolame_set_num_channels(s->glopts, avctx->channels);
     twolame_set_in_samplerate(s->glopts, avctx->sample_rate);
     twolame_set_out_samplerate(s->glopts, avctx->sample_rate);

 
     if (!avctx->bit_rate)
         avctx->bit_rate = avctx->sample_rate < 28000 ? 160000 : 384000;
 

     if (avctx->flags & AV_CODEC_FLAG_QSCALE || !avctx->bit_rate) {

         twolame_set_VBR(s->glopts, TRUE);

         twolame_set_VBR_level(s->glopts,
                               avctx->global_quality / (float) FF_QP2LAMBDA);
         av_log(avctx, AV_LOG_WARNING,
                "VBR in MP2 is a hack, use another codec that supports it.\n");

     } else {
         twolame_set_bitrate(s->glopts, avctx->bit_rate / 1000);
     }
 

     ret = twolame_init_params(s->glopts);
     if (ret) {
         twolame_encode_close(avctx);
         return AVERROR_UNKNOWN;
     }

 
     return 0;
 }
 
 static int twolame_encode_frame(AVCodecContext *avctx, AVPacket *avpkt,
                                 const AVFrame *frame, int *got_packet_ptr)
 {
     TWOLAMEContext *s = avctx->priv_data;
     int ret;
 

     if ((ret = ff_alloc_packet2(avctx, avpkt, MPA_MAX_CODED_FRAME_SIZE, 0)) < 0)

         return ret;
 
     if (frame) {
         switch (avctx->sample_fmt) {
         case AV_SAMPLE_FMT_FLT:
             ret = twolame_encode_buffer_float32_interleaved(s->glopts,

                                                             (const float *)frame->data[0],
                                                             frame->nb_samples,
                                                             avpkt->data,
                                                             avpkt->size);

             break;
         case AV_SAMPLE_FMT_FLTP:
             ret = twolame_encode_buffer_float32(s->glopts,

                                                 (const float *)frame->data[0],
                                                 (const float *)frame->data[1],
                                                 frame->nb_samples,
                                                 avpkt->data, avpkt->size);

             break;
         case AV_SAMPLE_FMT_S16:
             ret = twolame_encode_buffer_interleaved(s->glopts,

                                                     (const short int *)frame->data[0],
                                                     frame->nb_samples,
                                                     avpkt->data, avpkt->size);

             break;
         case AV_SAMPLE_FMT_S16P:
             ret = twolame_encode_buffer(s->glopts,

                                         (const short int *)frame->data[0],
                                         (const short int *)frame->data[1],

                                         frame->nb_samples,
                                         avpkt->data, avpkt->size);
             break;
         default:

             av_log(avctx, AV_LOG_ERROR,
                    "Unsupported sample format %d.\n", avctx->sample_fmt);

             return AVERROR_BUG;
         }
     } else {
         ret = twolame_encode_flush(s->glopts, avpkt->data, avpkt->size);
     }
 

     if (!ret)     // no bytes written

         return 0;

     if (ret < 0)  // twolame error
         return AVERROR_UNKNOWN;
 
     if (frame) {

         avpkt->duration = ff_samples_to_time_base(avctx, frame->nb_samples);

         if (frame->pts != AV_NOPTS_VALUE)

             avpkt->pts = frame->pts - ff_samples_to_time_base(avctx, avctx->initial_padding);

     } else {
         avpkt->pts = s->next_pts;

     }

     // this is for setting pts for flushed packet(s).
     if (avpkt->pts != AV_NOPTS_VALUE)
         s->next_pts = avpkt->pts + avpkt->duration;

     av_shrink_packet(avpkt, ret);
     *got_packet_ptr = 1;
     return 0;

 }
 
 #define OFFSET(x) offsetof(TWOLAMEContext, x)
 #define AE AV_OPT_FLAG_AUDIO_PARAM | AV_OPT_FLAG_ENCODING_PARAM
 static const AVOption options[] = {

     { "mode", "Mpeg Mode", OFFSET(mode), AV_OPT_TYPE_INT, { .i64 = TWOLAME_AUTO_MODE }, TWOLAME_AUTO_MODE, TWOLAME_MONO, AE, "mode"},
         { "auto", NULL, 0, AV_OPT_TYPE_CONST, { .i64 = TWOLAME_AUTO_MODE }, 0, 0, AE, "mode" },
         { "stereo", NULL, 0, AV_OPT_TYPE_CONST, { .i64 = TWOLAME_STEREO }, 0, 0, AE, "mode" },
         { "joint_stereo", NULL, 0, AV_OPT_TYPE_CONST, { .i64 = TWOLAME_JOINT_STEREO }, 0, 0, AE, "mode" },
         { "dual_channel", NULL, 0, AV_OPT_TYPE_CONST, { .i64 = TWOLAME_DUAL_CHANNEL }, 0, 0, AE, "mode" },
         { "mono", NULL, 0, AV_OPT_TYPE_CONST, { .i64 = TWOLAME_MONO }, 0, 0, AE, "mode" },
     { "psymodel", "Psychoacoustic Model", OFFSET(psymodel), AV_OPT_TYPE_INT, { .i64 = 3 }, -1, 4, AE},
     { "energy_levels","enable energy levels", OFFSET(energy), AV_OPT_TYPE_INT, { .i64 = 0 },  0, 1, AE},

     { "error_protection","enable CRC error protection", OFFSET(error_protection), AV_OPT_TYPE_INT, { .i64 = 0 },  0, 1, AE},

     { "copyright", "set MPEG Audio Copyright flag", OFFSET(copyright), AV_OPT_TYPE_INT, { .i64 = 0 }, 0, 1, AE},
     { "original", "set MPEG Audio Original flag", OFFSET(original), AV_OPT_TYPE_INT, { .i64 = 0 }, 0, 1, AE},
     { "verbosity", "set library optput level (0-10)", OFFSET(verbosity), AV_OPT_TYPE_INT, { .i64 = 0 }, 0, 10, AE},

     { NULL },
 };
 

 static const AVClass twolame_class = {

     .class_name = "libtwolame encoder",
     .item_name  = av_default_item_name,
     .option     = options,
     .version    = LIBAVUTIL_VERSION_INT,
 };
 

 static const AVCodecDefault twolame_defaults[] = {

     { "b", "0" },

     { NULL },
 };
 
 static const int twolame_samplerates[] = {
     16000, 22050, 24000, 32000, 44100, 48000, 0
 };
 

 AVCodec ff_libtwolame_encoder = {

     .name           = "libtwolame",
     .long_name      = NULL_IF_CONFIG_SMALL("libtwolame MP2 (MPEG audio layer 2)"),
     .type           = AVMEDIA_TYPE_AUDIO,
     .id             = AV_CODEC_ID_MP2,
     .priv_data_size = sizeof(TWOLAMEContext),
     .init           = twolame_encode_init,
     .encode2        = twolame_encode_frame,
     .close          = twolame_encode_close,

     .capabilities   = AV_CODEC_CAP_DELAY,

     .defaults       = twolame_defaults,
     .priv_class     = &twolame_class,
     .sample_fmts    = (const enum AVSampleFormat[]) {
         AV_SAMPLE_FMT_FLT,
         AV_SAMPLE_FMT_FLTP,
         AV_SAMPLE_FMT_S16,
         AV_SAMPLE_FMT_S16P,
         AV_SAMPLE_FMT_NONE
     },
     .channel_layouts = (const uint64_t[]) {
         AV_CH_LAYOUT_MONO,
         AV_CH_LAYOUT_STEREO,
         0 },
     .supported_samplerates = twolame_samplerates,

 };