/*
  * RTP JPEG-compressed Video Depacketizer, RFC 2435
  * Copyright (c) 2012 Samuel Pitoiset
  *

  * 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 "avformat.h"

 #include "avio_internal.h"

 #include "rtpdec.h"

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

 #include "libavcodec/jpegtables.h"

 #include "libavcodec/mjpeg.h"

 #include "libavcodec/bytestream.h"

 
 /**
  * RTP/JPEG specific private data.
  */
 struct PayloadContext {
     AVIOContext *frame;         ///< current frame buffer
     uint32_t    timestamp;      ///< current frame timestamp
     int         hdr_size;       ///< size of the current frame header

     uint8_t     qtables[128][128];
     uint8_t     qtables_len[128];

 };
 

 static const uint8_t default_quantizers[128] = {
     /* luma table */
     16,  11,  12,  14,  12,  10,  16,  14,
     13,  14,  18,  17,  16,  19,  24,  40,
     26,  24,  22,  22,  24,  49,  35,  37,
     29,  40,  58,  51,  61,  60,  57,  51,
     56,  55,  64,  72,  92,  78,  64,  68,
     87,  69,  55,  56,  80,  109, 81,  87,
     95,  98,  103, 104, 103, 62,  77,  113,
     121, 112, 100, 120, 92,  101, 103, 99,
 
     /* chroma table */
     17,  18,  18,  24,  21,  24,  47,  26,
     26,  47,  99,  66,  56,  66,  99,  99,
     99,  99,  99,  99,  99,  99,  99,  99,
     99,  99,  99,  99,  99,  99,  99,  99,
     99,  99,  99,  99,  99,  99,  99,  99,
     99,  99,  99,  99,  99,  99,  99,  99,
     99,  99,  99,  99,  99,  99,  99,  99,
     99,  99,  99,  99,  99,  99,  99,  99
 };
 

 static void jpeg_close_context(PayloadContext *jpeg)

 {

     ffio_free_dyn_buf(&jpeg->frame);

 }
 

 static int jpeg_create_huffman_table(PutByteContext *p, int table_class,

                                      int table_id, const uint8_t *bits_table,
                                      const uint8_t *value_table)

 {
     int i, n = 0;
 

     bytestream2_put_byte(p, table_class << 4 | table_id);

 
     for (i = 1; i <= 16; i++) {
         n += bits_table[i];

         bytestream2_put_byte(p, bits_table[i]);

     }
 
     for (i = 0; i < n; i++) {

         bytestream2_put_byte(p, value_table[i]);

     }

     return n + 17;

 }
 

 static void jpeg_put_marker(PutByteContext *pbc, int code)
 {
     bytestream2_put_byte(pbc, 0xff);
     bytestream2_put_byte(pbc, code);

 }
 
 static int jpeg_create_header(uint8_t *buf, int size, uint32_t type, uint32_t w,

                               uint32_t h, const uint8_t *qtable, int nb_qtable,
                               int dri)

 {

     PutByteContext pbc;

     uint8_t *dht_size_ptr;

     int dht_size, i;

     bytestream2_init_writer(&pbc, buf, size);

 
     /* Convert from blocks to pixels. */
     w <<= 3;
     h <<= 3;
 
     /* SOI */

     jpeg_put_marker(&pbc, SOI);

 
     /* JFIF header */

     jpeg_put_marker(&pbc, APP0);
     bytestream2_put_be16(&pbc, 16);
     bytestream2_put_buffer(&pbc, "JFIF", 5);
     bytestream2_put_be16(&pbc, 0x0201);
     bytestream2_put_byte(&pbc, 0);
     bytestream2_put_be16(&pbc, 1);
     bytestream2_put_be16(&pbc, 1);
     bytestream2_put_byte(&pbc, 0);
     bytestream2_put_byte(&pbc, 0);

     if (dri) {
         jpeg_put_marker(&pbc, DRI);
         bytestream2_put_be16(&pbc, 4);
         bytestream2_put_be16(&pbc, dri);
     }
 

     /* DQT */

     jpeg_put_marker(&pbc, DQT);
     bytestream2_put_be16(&pbc, 2 + nb_qtable * (1 + 64));

     for (i = 0; i < nb_qtable; i++) {

         bytestream2_put_byte(&pbc, i);

         /* Each table is an array of 64 values given in zig-zag
          * order, identical to the format used in a JFIF DQT
          * marker segment. */

         bytestream2_put_buffer(&pbc, qtable + 64 * i, 64);

     }
 
     /* DHT */

     jpeg_put_marker(&pbc, DHT);
     dht_size_ptr = pbc.buffer;
     bytestream2_put_be16(&pbc, 0);

 
     dht_size  = 2;
     dht_size += jpeg_create_huffman_table(&pbc, 0, 0,avpriv_mjpeg_bits_dc_luminance,
                                           avpriv_mjpeg_val_dc);
     dht_size += jpeg_create_huffman_table(&pbc, 0, 1, avpriv_mjpeg_bits_dc_chrominance,
                                           avpriv_mjpeg_val_dc);
     dht_size += jpeg_create_huffman_table(&pbc, 1, 0, avpriv_mjpeg_bits_ac_luminance,
                                           avpriv_mjpeg_val_ac_luminance);
     dht_size += jpeg_create_huffman_table(&pbc, 1, 1, avpriv_mjpeg_bits_ac_chrominance,
                                           avpriv_mjpeg_val_ac_chrominance);
     AV_WB16(dht_size_ptr, dht_size);

 
     /* SOF0 */

     jpeg_put_marker(&pbc, SOF0);

     bytestream2_put_be16(&pbc, 17); /* size */
     bytestream2_put_byte(&pbc, 8); /* bits per component */

     bytestream2_put_be16(&pbc, h);
     bytestream2_put_be16(&pbc, w);

     bytestream2_put_byte(&pbc, 3); /* number of components */
     bytestream2_put_byte(&pbc, 1); /* component number */

     bytestream2_put_byte(&pbc, (2 << 4) | (type ? 2 : 1)); /* hsample/vsample */

     bytestream2_put_byte(&pbc, 0); /* matrix number */
     bytestream2_put_byte(&pbc, 2); /* component number */

     bytestream2_put_byte(&pbc, 1 << 4 | 1); /* hsample/vsample */

     bytestream2_put_byte(&pbc, nb_qtable == 2 ? 1 : 0); /* matrix number */
     bytestream2_put_byte(&pbc, 3); /* component number */

     bytestream2_put_byte(&pbc, 1 << 4 | 1); /* hsample/vsample */

     bytestream2_put_byte(&pbc, nb_qtable == 2 ? 1 : 0); /* matrix number */

 
     /* SOS */

     jpeg_put_marker(&pbc, SOS);
     bytestream2_put_be16(&pbc, 12);
     bytestream2_put_byte(&pbc, 3);
     bytestream2_put_byte(&pbc, 1);
     bytestream2_put_byte(&pbc, 0);
     bytestream2_put_byte(&pbc, 2);
     bytestream2_put_byte(&pbc, 17);
     bytestream2_put_byte(&pbc, 3);
     bytestream2_put_byte(&pbc, 17);
     bytestream2_put_byte(&pbc, 0);
     bytestream2_put_byte(&pbc, 63);
     bytestream2_put_byte(&pbc, 0);

 
     /* Return the length in bytes of the JPEG header. */

     return bytestream2_tell_p(&pbc);

 }
 

 static void create_default_qtables(uint8_t *qtables, uint8_t q)
 {
     int factor = q;
     int i;

     uint16_t S;

 
     factor = av_clip(q, 1, 99);
 
     if (q < 50)

         S = 5000 / factor;

     else

         S = 200 - factor * 2;

 
     for (i = 0; i < 128; i++) {

         int val = (default_quantizers[i] * S + 50) / 100;

 
         /* Limit the quantizers to 1 <= q <= 255. */
         val = av_clip(val, 1, 255);
         qtables[i] = val;
     }
 }
 

 static int jpeg_parse_packet(AVFormatContext *ctx, PayloadContext *jpeg,
                              AVStream *st, AVPacket *pkt, uint32_t *timestamp,

                              const uint8_t *buf, int len, uint16_t seq,
                              int flags)

 {
     uint8_t type, q, width, height;
     const uint8_t *qtables = NULL;
     uint16_t qtable_len;
     uint32_t off;

     int ret, dri = 0;

 
     if (len < 8) {
         av_log(ctx, AV_LOG_ERROR, "Too short RTP/JPEG packet.\n");
         return AVERROR_INVALIDDATA;
     }
 
     /* Parse the main JPEG header. */
     off    = AV_RB24(buf + 1);  /* fragment byte offset */
     type   = AV_RB8(buf + 4);   /* id of jpeg decoder params */
     q      = AV_RB8(buf + 5);   /* quantization factor (or table id) */
     width  = AV_RB8(buf + 6);   /* frame width in 8 pixel blocks */
     height = AV_RB8(buf + 7);   /* frame height in 8 pixel blocks */
     buf += 8;
     len -= 8;
 

     if (type & 0x40) {
         if (len < 4) {
             av_log(ctx, AV_LOG_ERROR, "Too short RTP/JPEG packet.\n");
             return AVERROR_INVALIDDATA;
         }
         dri = AV_RB16(buf);
         buf += 4;
         len -= 4;
         type &= ~0x40;
     }

     if (type > 1) {

         avpriv_report_missing_feature(ctx, "RTP/JPEG type %"PRIu8, type);

         return AVERROR_PATCHWELCOME;
     }

 
     /* Parse the quantization table header. */

     if (off == 0) {
         /* Start of JPEG data packet. */
         uint8_t new_qtables[128];
         uint8_t hdr[1024];

         if (q > 127) {
             uint8_t precision;
             if (len < 4) {

                 av_log(ctx, AV_LOG_ERROR, "Too short RTP/JPEG packet.\n");
                 return AVERROR_INVALIDDATA;
             }
 

             /* The first byte is reserved for future use. */
             precision  = AV_RB8(buf + 1);    /* size of coefficients */
             qtable_len = AV_RB16(buf + 2);   /* length in bytes */
             buf += 4;
             len -= 4;

             if (precision)
                 av_log(ctx, AV_LOG_WARNING, "Only 8-bit precision is supported.\n");

             if (qtable_len > 0) {
                 if (len < qtable_len) {
                     av_log(ctx, AV_LOG_ERROR, "Too short RTP/JPEG packet.\n");
                     return AVERROR_INVALIDDATA;
                 }
                 qtables = buf;
                 buf += qtable_len;
                 len -= qtable_len;

                 if (q < 255) {
                     if (jpeg->qtables_len[q - 128] &&
                         (jpeg->qtables_len[q - 128] != qtable_len ||
                          memcmp(qtables, &jpeg->qtables[q - 128][0], qtable_len))) {
                         av_log(ctx, AV_LOG_WARNING,
                                "Quantization tables for q=%d changed\n", q);
                     } else if (!jpeg->qtables_len[q - 128] && qtable_len <= 128) {
                         memcpy(&jpeg->qtables[q - 128][0], qtables,
                                qtable_len);
                         jpeg->qtables_len[q - 128] = qtable_len;
                     }
                 }
             } else {
                 if (q == 255) {
                     av_log(ctx, AV_LOG_ERROR,
                            "Invalid RTP/JPEG packet. Quantization tables not found.\n");
                     return AVERROR_INVALIDDATA;
                 }
                 if (!jpeg->qtables_len[q - 128]) {
                     av_log(ctx, AV_LOG_ERROR,
                            "No quantization tables known for q=%d yet.\n", q);
                     return AVERROR_INVALIDDATA;
                 }
                 qtables    = &jpeg->qtables[q - 128][0];
                 qtable_len =  jpeg->qtables_len[q - 128];

             }

         } else { /* q <= 127 */

             if (q == 0 || q > 99) {
                 av_log(ctx, AV_LOG_ERROR, "Reserved q value %d\n", q);
                 return AVERROR_INVALIDDATA;
             }

             create_default_qtables(new_qtables, q);
             qtables    = new_qtables;
             qtable_len = sizeof(new_qtables);

         }

 
         /* Skip the current frame in case of the end packet
          * has been lost somewhere. */

         ffio_free_dyn_buf(&jpeg->frame);

 
         if ((ret = avio_open_dyn_buf(&jpeg->frame)) < 0)
             return ret;
         jpeg->timestamp = *timestamp;
 
         /* Generate a frame and scan headers that can be prepended to the
          * RTP/JPEG data payload to produce a JPEG compressed image in
          * interchange format. */
         jpeg->hdr_size = jpeg_create_header(hdr, sizeof(hdr), type, width,
                                             height, qtables,

                                             qtable_len / 64, dri);

 
         /* Copy JPEG header to frame buffer. */
         avio_write(jpeg->frame, hdr, jpeg->hdr_size);
     }
 
     if (!jpeg->frame) {
         av_log(ctx, AV_LOG_ERROR,
                "Received packet without a start chunk; dropping frame.\n");
         return AVERROR(EAGAIN);
     }
 
     if (jpeg->timestamp != *timestamp) {
         /* Skip the current frame if timestamp is incorrect.
          * A start packet has been lost somewhere. */

         ffio_free_dyn_buf(&jpeg->frame);

         av_log(ctx, AV_LOG_ERROR, "RTP timestamps don't match.\n");
         return AVERROR_INVALIDDATA;
     }
 
     if (off != avio_tell(jpeg->frame) - jpeg->hdr_size) {
         av_log(ctx, AV_LOG_ERROR,
                "Missing packets; dropping frame.\n");
         return AVERROR(EAGAIN);
     }
 
     /* Copy data to frame buffer. */
     avio_write(jpeg->frame, buf, len);
 
     if (flags & RTP_FLAG_MARKER) {
         /* End of JPEG data packet. */

         uint8_t buf[2] = { 0xff, EOI };

 
         /* Put EOI marker. */
         avio_write(jpeg->frame, buf, sizeof(buf));
 
         /* Prepare the JPEG packet. */

         if ((ret = ff_rtp_finalize_packet(pkt, &jpeg->frame, st->index)) < 0) {

             av_log(ctx, AV_LOG_ERROR,

                    "Error occurred when getting frame buffer.\n");

             return ret;

         }
 
         return 0;
     }
 
     return AVERROR(EAGAIN);
 }
 

 const RTPDynamicProtocolHandler ff_jpeg_dynamic_handler = {

     .enc_name          = "JPEG",
     .codec_type        = AVMEDIA_TYPE_VIDEO,
     .codec_id          = AV_CODEC_ID_MJPEG,

     .priv_data_size    = sizeof(PayloadContext),

     .close             = jpeg_close_context,

     .parse_packet      = jpeg_parse_packet,
     .static_payload_id = 26,
 };