/*

  * Psygnosis YOP demuxer
  *
  * Copyright (C) 2010 Mohamed Naufal Basheer <naufal11@gmail.com>
  * derived from the code by
  * Copyright (C) 2009 Thomas P. Higdon <thomas.p.higdon@gmail.com>
  *
  * 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 "libavutil/channel_layout.h"

 #include "libavutil/intreadwrite.h"
 #include "avformat.h"

 #include "internal.h"

 
 typedef struct yop_dec_context {
     AVPacket video_packet;
 
     int odd_frame;
     int frame_size;
     int audio_block_length;
     int palette_size;
 } YopDecContext;
 
 static int yop_probe(AVProbeData *probe_packet)
 {
     if (AV_RB16(probe_packet->buf) == AV_RB16("YO")  &&

         probe_packet->buf[2]<10                      &&
         probe_packet->buf[3]<10                      &&

         probe_packet->buf[6]                         &&
         probe_packet->buf[7]                         &&
         !(probe_packet->buf[8] & 1)                  &&

         !(probe_packet->buf[10] & 1)                 &&
         AV_RL16(probe_packet->buf + 12 + 6) >= 920    &&
         AV_RL16(probe_packet->buf + 12 + 6) < probe_packet->buf[12] * 3 + 4 + probe_packet->buf[7] * 2048
     )

         return AVPROBE_SCORE_MAX * 3 / 4;
 
     return 0;
 }
 

 static int yop_read_header(AVFormatContext *s)

 {
     YopDecContext *yop = s->priv_data;

     AVIOContext *pb  = s->pb;

 
     AVCodecContext *audio_dec, *video_dec;
     AVStream *audio_stream, *video_stream;
 
     int frame_rate, ret;
 

     audio_stream = avformat_new_stream(s, NULL);

     video_stream = avformat_new_stream(s, NULL);

     if (!audio_stream || !video_stream)
         return AVERROR(ENOMEM);

 
     // Extra data that will be passed to the decoder
     video_stream->codec->extradata_size = 8;
 
     video_stream->codec->extradata = av_mallocz(video_stream->codec->extradata_size +
                                                 FF_INPUT_BUFFER_PADDING_SIZE);
 
     if (!video_stream->codec->extradata)
         return AVERROR(ENOMEM);
 
     // Audio
     audio_dec               = audio_stream->codec;

     audio_dec->codec_type   = AVMEDIA_TYPE_AUDIO;

     audio_dec->codec_id     = AV_CODEC_ID_ADPCM_IMA_APC;

     audio_dec->channels     = 1;

     audio_dec->channel_layout = AV_CH_LAYOUT_MONO;

     audio_dec->sample_rate  = 22050;
 
     // Video
     video_dec               = video_stream->codec;

     video_dec->codec_type   = AVMEDIA_TYPE_VIDEO;

     video_dec->codec_id     = AV_CODEC_ID_YOP;

     avio_skip(pb, 6);

     frame_rate              = avio_r8(pb);
     yop->frame_size         = avio_r8(pb) * 2048;
     video_dec->width        = avio_rl16(pb);
     video_dec->height       = avio_rl16(pb);

 
     video_stream->sample_aspect_ratio = (AVRational){1, 2};
 

     ret = avio_read(pb, video_dec->extradata, 8);

     if (ret < 8)
         return ret < 0 ? ret : AVERROR_EOF;
 
     yop->palette_size       = video_dec->extradata[0] * 3 + 4;
     yop->audio_block_length = AV_RL16(video_dec->extradata + 6);
 

     video_dec->bit_rate     = 8 * (yop->frame_size - yop->audio_block_length) * frame_rate;
 

     // 1840 samples per frame, 1 nibble per sample; hence 1840/2 = 920
     if (yop->audio_block_length < 920 ||
         yop->audio_block_length + yop->palette_size >= yop->frame_size) {
         av_log(s, AV_LOG_ERROR, "YOP has invalid header\n");
         return AVERROR_INVALIDDATA;
     }
 

     avio_seek(pb, 2048, SEEK_SET);

     avpriv_set_pts_info(video_stream, 32, 1, frame_rate);

 
     return 0;
 }
 
 static int yop_read_packet(AVFormatContext *s, AVPacket *pkt)
 {
     YopDecContext *yop = s->priv_data;

     AVIOContext *pb  = s->pb;

 
     int ret;
     int actual_video_data_size = yop->frame_size -
                                  yop->audio_block_length - yop->palette_size;
 
     yop->video_packet.stream_index = 1;
 
     if (yop->video_packet.data) {
         *pkt                   =  yop->video_packet;
         yop->video_packet.data =  NULL;
         yop->video_packet.size =  0;
         pkt->data[0]           =  yop->odd_frame;

         pkt->flags             |= AV_PKT_FLAG_KEY;

         yop->odd_frame         ^= 1;
         return pkt->size;
     }
     ret = av_new_packet(&yop->video_packet,
                         yop->frame_size - yop->audio_block_length);
     if (ret < 0)
         return ret;
 

     yop->video_packet.pos = avio_tell(pb);

     ret = avio_read(pb, yop->video_packet.data, yop->palette_size);

     if (ret < 0) {
         goto err_out;
     }else if (ret < yop->palette_size) {
         ret = AVERROR_EOF;
         goto err_out;
     }
 
     ret = av_get_packet(pb, pkt, 920);
     if (ret < 0)
         goto err_out;
 
     // Set position to the start of the frame
     pkt->pos = yop->video_packet.pos;
 

     avio_skip(pb, yop->audio_block_length - ret);

     ret = avio_read(pb, yop->video_packet.data + yop->palette_size,

                      actual_video_data_size);
     if (ret < 0)
         goto err_out;
     else if (ret < actual_video_data_size)
         av_shrink_packet(&yop->video_packet, yop->palette_size + ret);
 
     // Arbitrarily return the audio data first
     return yop->audio_block_length;
 
 err_out:
     av_free_packet(&yop->video_packet);
     return ret;
 }
 
 static int yop_read_close(AVFormatContext *s)
 {
     YopDecContext *yop = s->priv_data;
     av_free_packet(&yop->video_packet);
     return 0;
 }
 
 static int yop_read_seek(AVFormatContext *s, int stream_index,
                          int64_t timestamp, int flags)
 {
     YopDecContext *yop = s->priv_data;
     int64_t frame_pos, pos_min, pos_max;
     int frame_count;
 
     if (!stream_index)
         return -1;
 
     pos_min        = s->data_offset;

     pos_max        = avio_size(s->pb) - yop->frame_size;

     frame_count    = (pos_max - pos_min) / yop->frame_size;
 
     timestamp      = FFMAX(0, FFMIN(frame_count, timestamp));
 
     frame_pos      = timestamp * yop->frame_size + pos_min;

 
     if (avio_seek(s->pb, frame_pos, SEEK_SET) < 0)
         return -1;
 
     av_free_packet(&yop->video_packet);

     yop->odd_frame = timestamp & 1;
 
     return 0;
 }
 

 AVInputFormat ff_yop_demuxer = {

     .name           = "yop",

     .long_name      = NULL_IF_CONFIG_SMALL("Psygnosis YOP"),

     .priv_data_size = sizeof(YopDecContext),
     .read_probe     = yop_probe,
     .read_header    = yop_read_header,
     .read_packet    = yop_read_packet,
     .read_close     = yop_read_close,
     .read_seek      = yop_read_seek,

     .extensions     = "yop",
     .flags          = AVFMT_GENERIC_INDEX,

 };