/*
  * Interface to libgsm for GSM encoding
  * Copyright (c) 2005 Alban Bedel <albeu@free.fr>
  * Copyright (c) 2006, 2007 Michel Bardiaux <mbardiaux@mediaxim.be>
  *

  * 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 libgsm for GSM encoding
  */
 
 // The idiosyncrasies of GSM-in-WAV are explained at http://kbs.cs.tu-berlin.de/~jutta/toast.html
 
 #include "config.h"
 #if HAVE_GSM_H
 #include <gsm.h>
 #else
 #include <gsm/gsm.h>
 #endif
 
 #include "libavutil/common.h"
 
 #include "avcodec.h"
 #include "internal.h"
 #include "gsm.h"
 

 static av_cold int libgsm_encode_close(AVCodecContext *avctx) {
     gsm_destroy(avctx->priv_data);
     avctx->priv_data = NULL;
     return 0;
 }
 

 static av_cold int libgsm_encode_init(AVCodecContext *avctx) {
     if (avctx->channels > 1) {
         av_log(avctx, AV_LOG_ERROR, "Mono required for GSM, got %d channels\n",
                avctx->channels);
         return -1;
     }
 
     if (avctx->sample_rate != 8000) {
         av_log(avctx, AV_LOG_ERROR, "Sample rate 8000Hz required for GSM, got %dHz\n",
                avctx->sample_rate);
         if (avctx->strict_std_compliance > FF_COMPLIANCE_UNOFFICIAL)
             return -1;
     }
     if (avctx->bit_rate != 13000 /* Official */ &&
         avctx->bit_rate != 13200 /* Very common */ &&
         avctx->bit_rate != 0 /* Unknown; a.o. mov does not set bitrate when decoding */ ) {

         av_log(avctx, AV_LOG_ERROR, "Bitrate 13000bps required for GSM, got %"PRId64"bps\n",

                avctx->bit_rate);

         if (avctx->strict_std_compliance > FF_COMPLIANCE_UNOFFICIAL)
             return -1;
     }
 
     avctx->priv_data = gsm_create();

     if (!avctx->priv_data)
         goto error;

 
     switch(avctx->codec_id) {
     case AV_CODEC_ID_GSM:
         avctx->frame_size = GSM_FRAME_SIZE;
         avctx->block_align = GSM_BLOCK_SIZE;
         break;
     case AV_CODEC_ID_GSM_MS: {
         int one = 1;
         gsm_option(avctx->priv_data, GSM_OPT_WAV49, &one);
         avctx->frame_size = 2*GSM_FRAME_SIZE;
         avctx->block_align = GSM_MS_BLOCK_SIZE;
         }
     }
 
     return 0;

 error:
     libgsm_encode_close(avctx);
     return -1;

 }
 
 static int libgsm_encode_frame(AVCodecContext *avctx, AVPacket *avpkt,
                                const AVFrame *frame, int *got_packet_ptr)
 {
     int ret;
     gsm_signal *samples = (gsm_signal *)frame->data[0];
     struct gsm_state *state = avctx->priv_data;
 

     if ((ret = ff_alloc_packet2(avctx, avpkt, avctx->block_align, 0)) < 0)

         return ret;
 
     switch(avctx->codec_id) {
     case AV_CODEC_ID_GSM:
         gsm_encode(state, samples, avpkt->data);
         break;
     case AV_CODEC_ID_GSM_MS:
         gsm_encode(state, samples,                  avpkt->data);
         gsm_encode(state, samples + GSM_FRAME_SIZE, avpkt->data + 32);
     }
 
     *got_packet_ptr = 1;
     return 0;
 }
 
 

 #if CONFIG_LIBGSM_ENCODER

 AVCodec ff_libgsm_encoder = {
     .name           = "libgsm",
     .long_name      = NULL_IF_CONFIG_SMALL("libgsm GSM"),
     .type           = AVMEDIA_TYPE_AUDIO,
     .id             = AV_CODEC_ID_GSM,
     .init           = libgsm_encode_init,
     .encode2        = libgsm_encode_frame,
     .close          = libgsm_encode_close,
     .sample_fmts    = (const enum AVSampleFormat[]){ AV_SAMPLE_FMT_S16,
                                                      AV_SAMPLE_FMT_NONE },
 };

 #endif
 #if CONFIG_LIBGSM_MS_ENCODER

 AVCodec ff_libgsm_ms_encoder = {
     .name           = "libgsm_ms",
     .long_name      = NULL_IF_CONFIG_SMALL("libgsm GSM Microsoft variant"),
     .type           = AVMEDIA_TYPE_AUDIO,
     .id             = AV_CODEC_ID_GSM_MS,
     .init           = libgsm_encode_init,
     .encode2        = libgsm_encode_frame,
     .close          = libgsm_encode_close,
     .sample_fmts    = (const enum AVSampleFormat[]){ AV_SAMPLE_FMT_S16,
                                                      AV_SAMPLE_FMT_NONE },
 };

 #endif