/*
  * Bethsoft VID format Demuxer
  * Copyright (c) 2007 Nicholas Tung
  *
  * 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

  * @brief Bethesda Softworks VID (.vid) file demuxer
  * @author Nicholas Tung [ntung (at. ntung com] (2007-03)

  * @see http://wiki.multimedia.cx/index.php?title=Bethsoft_VID
  * @see http://www.svatopluk.com/andux/docs/dfvid.html

  */
 

 #include "libavutil/intreadwrite.h"

 #include "avformat.h"

 #include "internal.h"

 #include "libavcodec/bethsoftvideo.h"

 
 typedef struct BVID_DemuxContext
 {
     int nframes;
     /** delay value between frames, added to individual frame delay.
      * custom units, which will be added to other custom units (~=16ms according
      * to free, unofficial documentation) */
     int bethsoft_global_delay;
 
     /** video presentation time stamp.
      * delay = 16 milliseconds * (global_delay + per_frame_delay) */

     int video_pts;

 
     int is_finished;
 
 } BVID_DemuxContext;
 
 static int vid_probe(AVProbeData *p)
 {
     // little endian VID tag, file starts with "VID\0"

     if (AV_RL32(p->buf) != MKTAG('V', 'I', 'D', 0))

         return 0;
 
     return AVPROBE_SCORE_MAX;
 }
 
 static int vid_read_header(AVFormatContext *s,
                             AVFormatParameters *ap)
 {

     BVID_DemuxContext *vid = s->priv_data;

     AVIOContext *pb = s->pb;

     AVStream *stream;
 
     /* load main header. Contents:
     *    bytes: 'V' 'I' 'D'
     *    int16s: always_512, nframes, width, height, delay, always_14
     */

     avio_skip(pb, 5);

     vid->nframes = avio_rl16(pb);

     stream = avformat_new_stream(s, NULL);

     if (!stream)

         return AVERROR(ENOMEM);

     avpriv_set_pts_info(stream, 32, 1, 60);     // 16 ms increments, i.e. 60 fps

     stream->codec->codec_type = AVMEDIA_TYPE_VIDEO;

     stream->codec->codec_id = CODEC_ID_BETHSOFTVID;

     stream->codec->width = avio_rl16(pb);
     stream->codec->height = avio_rl16(pb);

     stream->codec->pix_fmt = PIX_FMT_PAL8;

     vid->bethsoft_global_delay = avio_rl16(pb);
     avio_rl16(pb);

 
     // done with video codec, set up audio codec

     stream = avformat_new_stream(s, NULL);

     if (!stream)

         return AVERROR(ENOMEM);

     stream->codec->codec_type = AVMEDIA_TYPE_AUDIO;

     stream->codec->codec_id = CODEC_ID_PCM_U8;
     stream->codec->channels = 1;
     stream->codec->sample_rate = 11025;

     stream->codec->bits_per_coded_sample = 8;
     stream->codec->bit_rate = stream->codec->channels * stream->codec->sample_rate * stream->codec->bits_per_coded_sample;

 
     return 0;
 }
 
 #define BUFFER_PADDING_SIZE 1000

 static int read_frame(BVID_DemuxContext *vid, AVIOContext *pb, AVPacket *pkt,

                       uint8_t block_type, AVFormatContext *s, int npixels)
 {
     uint8_t * vidbuf_start = NULL;
     int vidbuf_nbytes = 0;

     int code;

     int bytes_copied = 0;
     int position;

     unsigned int vidbuf_capacity;

 
     vidbuf_start = av_malloc(vidbuf_capacity = BUFFER_PADDING_SIZE);

     if(!vidbuf_start)

         return AVERROR(ENOMEM);

 
     // save the file position for the packet, include block type

     position = avio_tell(pb) - 1;

 
     vidbuf_start[vidbuf_nbytes++] = block_type;
 
     // get the video delay (next int16), and set the presentation time

     vid->video_pts += vid->bethsoft_global_delay + avio_rl16(pb);

 
     // set the y offset if it exists (decoder header data should be in data section)

     if(block_type == VIDEO_YOFF_P_FRAME){

         if(avio_read(pb, &vidbuf_start[vidbuf_nbytes], 2) != 2)

             goto fail;

         vidbuf_nbytes += 2;
     }
 

     do{

         vidbuf_start = av_fast_realloc(vidbuf_start, &vidbuf_capacity, vidbuf_nbytes + BUFFER_PADDING_SIZE);

         if(!vidbuf_start)

             return AVERROR(ENOMEM);

         code = avio_r8(pb);

         vidbuf_start[vidbuf_nbytes++] = code;

         if(code >= 0x80){ // rle sequence

             if(block_type == VIDEO_I_FRAME)

                 vidbuf_start[vidbuf_nbytes++] = avio_r8(pb);

         } else if(code){ // plain sequence

             if(avio_read(pb, &vidbuf_start[vidbuf_nbytes], code) != code)

                 goto fail;

             vidbuf_nbytes += code;

         }

         bytes_copied += code & 0x7F;

         if(bytes_copied == npixels){ // sometimes no stop character is given, need to keep track of bytes copied

             // may contain a 0 byte even if read all pixels

             if(avio_r8(pb))

                 avio_seek(pb, -1, SEEK_CUR);

             break;
         }

         if(bytes_copied > npixels)

             goto fail;

     } while(code);

 
     // copy data into packet

     if(av_new_packet(pkt, vidbuf_nbytes) < 0)
         goto fail;

     memcpy(pkt->data, vidbuf_start, vidbuf_nbytes);
     av_free(vidbuf_start);
 
     pkt->pos = position;
     pkt->stream_index = 0;  // use the video decoder, which was initialized as the first stream
     pkt->pts = vid->video_pts;
 
     vid->nframes--;  // used to check if all the frames were read
     return vidbuf_nbytes;

 fail:
     av_free(vidbuf_start);
     return -1;

 }
 
 static int vid_read_packet(AVFormatContext *s,
                            AVPacket *pkt)
 {

     BVID_DemuxContext *vid = s->priv_data;

     AVIOContext *pb = s->pb;

     unsigned char block_type;

     int audio_length;
     int ret_value;
 

     if(vid->is_finished || url_feof(pb))

         return AVERROR(EIO);

     block_type = avio_r8(pb);

     switch(block_type){

         case PALETTE_BLOCK:

             avio_seek(pb, -1, SEEK_CUR);     // include block type

             ret_value = av_get_packet(pb, pkt, 3 * 256 + 1);
             if(ret_value != 3 * 256 + 1){

                 av_free_packet(pkt);

                 return AVERROR(EIO);

             }

             pkt->stream_index = 0;
             return ret_value;
 
         case FIRST_AUDIO_BLOCK:

             avio_rl16(pb);

             // soundblaster DAC used for sample rate, as on specification page (link above)

             s->streams[1]->codec->sample_rate = 1000000 / (256 - avio_r8(pb));

             s->streams[1]->codec->bit_rate = s->streams[1]->codec->channels * s->streams[1]->codec->sample_rate * s->streams[1]->codec->bits_per_coded_sample;

         case AUDIO_BLOCK:

             audio_length = avio_rl16(pb);

             ret_value = av_get_packet(pb, pkt, audio_length);
             pkt->stream_index = 1;

             return ret_value != audio_length ? AVERROR(EIO) : ret_value;

         case VIDEO_P_FRAME:
         case VIDEO_YOFF_P_FRAME:
         case VIDEO_I_FRAME:

             return read_frame(vid, pb, pkt, block_type, s,
                               s->streams[0]->codec->width * s->streams[0]->codec->height);
 

         case EOF_BLOCK:

             if(vid->nframes != 0)
                 av_log(s, AV_LOG_VERBOSE, "reached terminating character but not all frames read.\n");
             vid->is_finished = 1;

             return AVERROR(EIO);

         default:
             av_log(s, AV_LOG_ERROR, "unknown block (character = %c, decimal = %d, hex = %x)!!!\n",
                    block_type, block_type, block_type); return -1;
     }
 }
 

 AVInputFormat ff_bethsoftvid_demuxer = {

     .name           = "bethsoftvid",
     .long_name      = NULL_IF_CONFIG_SMALL("Bethesda Softworks VID format"),
     .priv_data_size = sizeof(BVID_DemuxContext),
     .read_probe     = vid_probe,
     .read_header    = vid_read_header,
     .read_packet    = vid_read_packet,

 };