/*
  * Ut Video encoder
  * Copyright (c) 2012 Jan Ekström
  *

  * 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
  * Ut Video encoder
  */
 

 #include "libavutil/imgutils.h"

 #include "libavutil/intreadwrite.h"

 #include "libavutil/opt.h"
 

 #include "avcodec.h"
 #include "internal.h"

 #include "bswapdsp.h"

 #include "bytestream.h"
 #include "put_bits.h"

 #include "huffyuvencdsp.h"

 #include "mathops.h"
 #include "utvideo.h"

 #include "huffman.h"

 
 /* Compare huffentry symbols */
 static int huff_cmp_sym(const void *a, const void *b)
 {
     const HuffEntry *aa = a, *bb = b;
     return aa->sym - bb->sym;
 }
 
 static av_cold int utvideo_encode_close(AVCodecContext *avctx)
 {
     UtvideoContext *c = avctx->priv_data;

     int i;

 
     av_freep(&c->slice_bits);

     for (i = 0; i < 4; i++)
         av_freep(&c->slice_buffer[i]);

 
     return 0;
 }
 
 static av_cold int utvideo_encode_init(AVCodecContext *avctx)
 {
     UtvideoContext *c = avctx->priv_data;

     int i, subsampled_height;

     uint32_t original_format;
 
     c->avctx           = avctx;
     c->frame_info_size = 4;

     c->slice_stride    = FFALIGN(avctx->width, 32);

 
     switch (avctx->pix_fmt) {

     case AV_PIX_FMT_RGB24:

         c->planes        = 3;
         avctx->codec_tag = MKTAG('U', 'L', 'R', 'G');
         original_format  = UTVIDEO_RGB;
         break;

     case AV_PIX_FMT_RGBA:

         c->planes        = 4;
         avctx->codec_tag = MKTAG('U', 'L', 'R', 'A');
         original_format  = UTVIDEO_RGBA;

         avctx->bits_per_coded_sample = 32;

         break;

     case AV_PIX_FMT_YUV420P:

         if (avctx->width & 1 || avctx->height & 1) {
             av_log(avctx, AV_LOG_ERROR,
                    "4:2:0 video requires even width and height.\n");
             return AVERROR_INVALIDDATA;
         }
         c->planes        = 3;

         if (avctx->colorspace == AVCOL_SPC_BT709)
             avctx->codec_tag = MKTAG('U', 'L', 'H', '0');
         else
             avctx->codec_tag = MKTAG('U', 'L', 'Y', '0');

         original_format  = UTVIDEO_420;
         break;

     case AV_PIX_FMT_YUV422P:

         if (avctx->width & 1) {
             av_log(avctx, AV_LOG_ERROR,
                    "4:2:2 video requires even width.\n");
             return AVERROR_INVALIDDATA;
         }
         c->planes        = 3;

         if (avctx->colorspace == AVCOL_SPC_BT709)
             avctx->codec_tag = MKTAG('U', 'L', 'H', '2');
         else
             avctx->codec_tag = MKTAG('U', 'L', 'Y', '2');

         original_format  = UTVIDEO_422;
         break;

     case AV_PIX_FMT_YUV444P:
         c->planes        = 3;
         if (avctx->colorspace == AVCOL_SPC_BT709)
             avctx->codec_tag = MKTAG('U', 'L', 'H', '4');
         else
             avctx->codec_tag = MKTAG('U', 'L', 'Y', '4');
         original_format  = UTVIDEO_444;
         break;

     default:
         av_log(avctx, AV_LOG_ERROR, "Unknown pixel format: %d\n",
                avctx->pix_fmt);
         return AVERROR_INVALIDDATA;
     }
 

     ff_bswapdsp_init(&c->bdsp);

     ff_huffyuvencdsp_init(&c->hdsp);

 #if FF_API_PRIVATE_OPT
 FF_DISABLE_DEPRECATION_WARNINGS

     /* Check the prediction method, and error out if unsupported */
     if (avctx->prediction_method < 0 || avctx->prediction_method > 4) {
         av_log(avctx, AV_LOG_WARNING,
                "Prediction method %d is not supported in Ut Video.\n",
                avctx->prediction_method);
         return AVERROR_OPTION_NOT_FOUND;
     }
 
     if (avctx->prediction_method == FF_PRED_PLANE) {
         av_log(avctx, AV_LOG_ERROR,
                "Plane prediction is not supported in Ut Video.\n");
         return AVERROR_OPTION_NOT_FOUND;
     }
 
     /* Convert from libavcodec prediction type to Ut Video's */

     if (avctx->prediction_method)
         c->frame_pred = ff_ut_pred_order[avctx->prediction_method];
 FF_ENABLE_DEPRECATION_WARNINGS
 #endif

 
     if (c->frame_pred == PRED_GRADIENT) {
         av_log(avctx, AV_LOG_ERROR, "Gradient prediction is not supported.\n");
         return AVERROR_OPTION_NOT_FOUND;
     }
 

     /*
      * Check the asked slice count for obviously invalid
      * values (> 256 or negative).
      */
     if (avctx->slices > 256 || avctx->slices < 0) {
         av_log(avctx, AV_LOG_ERROR,
                "Slice count %d is not supported in Ut Video (theoretical range is 0-256).\n",
                avctx->slices);
         return AVERROR(EINVAL);
     }
 
     /* Check that the slice count is not larger than the subsampled height */
     subsampled_height = avctx->height >> av_pix_fmt_desc_get(avctx->pix_fmt)->log2_chroma_h;
     if (avctx->slices > subsampled_height) {
         av_log(avctx, AV_LOG_ERROR,
                "Slice count %d is larger than the subsampling-applied height %d.\n",
                avctx->slices, subsampled_height);
         return AVERROR(EINVAL);
     }
 

     /* extradata size is 4 * 32 bits */

     avctx->extradata_size = 16;
 
     avctx->extradata = av_mallocz(avctx->extradata_size +

                                   AV_INPUT_BUFFER_PADDING_SIZE);

 
     if (!avctx->extradata) {
         av_log(avctx, AV_LOG_ERROR, "Could not allocate extradata.\n");
         utvideo_encode_close(avctx);
         return AVERROR(ENOMEM);
     }
 

     for (i = 0; i < c->planes; i++) {

         c->slice_buffer[i] = av_malloc(c->slice_stride * (avctx->height + 2) +

                                        AV_INPUT_BUFFER_PADDING_SIZE);

         if (!c->slice_buffer[i]) {
             av_log(avctx, AV_LOG_ERROR, "Cannot allocate temporary buffer 1.\n");
             utvideo_encode_close(avctx);
             return AVERROR(ENOMEM);
         }

     }
 
     /*
      * Set the version of the encoder.
      * Last byte is "implementation ID", which is
      * obtained from the creator of the format.
      * Libavcodec has been assigned with the ID 0xF0.
      */
     AV_WB32(avctx->extradata, MKTAG(1, 0, 0, 0xF0));
 
     /*
      * Set the "original format"
      * Not used for anything during decoding.
      */
     AV_WL32(avctx->extradata + 4, original_format);
 
     /* Write 4 as the 'frame info size' */
     AV_WL32(avctx->extradata + 8, c->frame_info_size);
 
     /*
      * Set how many slices are going to be used.

      * By default uses multiple slices depending on the subsampled height.
      * This enables multithreading in the official decoder.

      */

     if (!avctx->slices) {
         c->slices = subsampled_height / 120;
 

         if (!c->slices)

             c->slices = 1;

         else if (c->slices > 256)

             c->slices = 256;
     } else {
         c->slices = avctx->slices;
     }

 
     /* Set compression mode */
     c->compression = COMP_HUFF;
 
     /*
      * Set the encoding flags:
      * - Slice count minus 1
      * - Interlaced encoding mode flag, set to zero for now.
      * - Compression mode (none/huff)
      * And write the flags.
      */
     c->flags  = (c->slices - 1) << 24;
     c->flags |= 0 << 11; // bit field to signal interlaced encoding mode
     c->flags |= c->compression;
 
     AV_WL32(avctx->extradata + 12, c->flags);
 
     return 0;
 }
 

 static void mangle_rgb_planes(uint8_t *dst[4], int dst_stride, uint8_t *src,
                               int step, int stride, int width, int height)

 {
     int i, j;

     int k = 2 * dst_stride;

     unsigned int g;

 
     for (j = 0; j < height; j++) {

         if (step == 3) {
             for (i = 0; i < width * step; i += step) {
                 g         = src[i + 1];
                 dst[0][k] = g;

                 g        += 0x80;

                 dst[1][k] = src[i + 2] - g;
                 dst[2][k] = src[i + 0] - g;
                 k++;
             }
         } else {
             for (i = 0; i < width * step; i += step) {
                 g         = src[i + 1];
                 dst[0][k] = g;

                 g        += 0x80;

                 dst[1][k] = src[i + 2] - g;
                 dst[2][k] = src[i + 0] - g;
                 dst[3][k] = src[i + 3];
                 k++;
             }

         }

         k += dst_stride - width;

         src += stride;
     }
 }
 
 /* Write data to a plane with left prediction */

 static void left_predict(uint8_t *src, uint8_t *dst, int stride,

                          int width, int height)
 {
     int i, j;
     uint8_t prev;
 
     prev = 0x80; /* Set the initial value */
     for (j = 0; j < height; j++) {

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

             *dst++ = src[i] - prev;
             prev   = src[i];
         }
         src += stride;
     }
 }
 
 /* Write data to a plane with median prediction */

 static void median_predict(UtvideoContext *c, uint8_t *src, uint8_t *dst, int stride,

                            int width, int height)
 {
     int i, j;

     int A, B;

     uint8_t prev;
 
     /* First line uses left neighbour prediction */
     prev = 0x80; /* Set the initial value */

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

         *dst++ = src[i] - prev;
         prev   = src[i];
     }
 
     if (height == 1)
         return;
 
     src += stride;
 
     /*
      * Second line uses top prediction for the first sample,
      * and median for the rest.
      */

     A = B = 0;

 
     /* Rest of the coded part uses median prediction */

     for (j = 1; j < height; j++) {

         c->hdsp.sub_hfyu_median_pred(dst, src - stride, src, width, &A, &B);

         dst += width;

         src += stride;
     }
 }
 
 /* Count the usage of values in a plane */
 static void count_usage(uint8_t *src, int width,

                         int height, uint64_t *counts)

 {
     int i, j;
 
     for (j = 0; j < height; j++) {
         for (i = 0; i < width; i++) {
             counts[src[i]]++;
         }
         src += width;
     }
 }
 
 /* Calculate the actual huffman codes from the code lengths */
 static void calculate_codes(HuffEntry *he)
 {
     int last, i;
     uint32_t code;
 
     qsort(he, 256, sizeof(*he), ff_ut_huff_cmp_len);
 
     last = 255;
     while (he[last].len == 255 && last)
         last--;
 
     code = 1;
     for (i = last; i >= 0; i--) {
         he[i].code  = code >> (32 - he[i].len);
         code       += 0x80000000u >> (he[i].len - 1);
     }
 
     qsort(he, 256, sizeof(*he), huff_cmp_sym);
 }
 
 /* Write huffman bit codes to a memory block */
 static int write_huff_codes(uint8_t *src, uint8_t *dst, int dst_size,
                             int width, int height, HuffEntry *he)
 {
     PutBitContext pb;
     int i, j;
     int count;
 
     init_put_bits(&pb, dst, dst_size);
 
     /* Write the codes */
     for (j = 0; j < height; j++) {
         for (i = 0; i < width; i++)
             put_bits(&pb, he[src[i]].len, he[src[i]].code);
 
         src += width;
     }
 

     /* Pad output to a 32-bit boundary */

     count = put_bits_count(&pb) & 0x1F;
 
     if (count)
         put_bits(&pb, 32 - count, 0);
 
     /* Get the amount of bits written */
     count = put_bits_count(&pb);
 
     /* Flush the rest with zeroes */
     flush_put_bits(&pb);
 
     return count;
 }
 
 static int encode_plane(AVCodecContext *avctx, uint8_t *src,

                         uint8_t *dst, int stride, int plane_no,

                         int width, int height, PutByteContext *pb)
 {
     UtvideoContext *c        = avctx->priv_data;
     uint8_t  lengths[256];

     uint64_t counts[256]     = { 0 };

 
     HuffEntry he[256];
 
     uint32_t offset = 0, slice_len = 0;

     const int cmask = ~(!plane_no && avctx->pix_fmt == AV_PIX_FMT_YUV420P);

     int      i, sstart, send = 0;
     int      symbol;

     int      ret;

 
     /* Do prediction / make planes */
     switch (c->frame_pred) {
     case PRED_NONE:
         for (i = 0; i < c->slices; i++) {
             sstart = send;

             send   = height * (i + 1) / c->slices & cmask;

             av_image_copy_plane(dst + sstart * width, width,
                                 src + sstart * stride, stride,
                                 width, send - sstart);

         }
         break;
     case PRED_LEFT:
         for (i = 0; i < c->slices; i++) {
             sstart = send;

             send   = height * (i + 1) / c->slices & cmask;

             left_predict(src + sstart * stride, dst + sstart * width,

                          stride, width, send - sstart);

         }
         break;
     case PRED_MEDIAN:
         for (i = 0; i < c->slices; i++) {
             sstart = send;

             send   = height * (i + 1) / c->slices & cmask;

             median_predict(c, src + sstart * stride, dst + sstart * width,

                            stride, width, send - sstart);

         }
         break;
     default:
         av_log(avctx, AV_LOG_ERROR, "Unknown prediction mode: %d\n",
                c->frame_pred);
         return AVERROR_OPTION_NOT_FOUND;
     }
 
     /* Count the usage of values */
     count_usage(dst, width, height, counts);
 
     /* Check for a special case where only one symbol was used */
     for (symbol = 0; symbol < 256; symbol++) {
         /* If non-zero count is found, see if it matches width * height */
         if (counts[symbol]) {
             /* Special case if only one symbol was used */

             if (counts[symbol] == width * (int64_t)height) {

                 /*
                  * Write a zero for the single symbol
                  * used in the plane, else 0xFF.
                  */
                 for (i = 0; i < 256; i++) {
                     if (i == symbol)
                         bytestream2_put_byte(pb, 0);
                     else
                         bytestream2_put_byte(pb, 0xFF);
                 }
 
                 /* Write zeroes for lengths */
                 for (i = 0; i < c->slices; i++)
                     bytestream2_put_le32(pb, 0);
 
                 /* And that's all for that plane folks */
                 return 0;
             }
             break;
         }
     }
 
     /* Calculate huffman lengths */

     if ((ret = ff_huff_gen_len_table(lengths, counts, 256, 1)) < 0)

         return ret;

 
     /*
      * Write the plane's header into the output packet:
      * - huffman code lengths (256 bytes)
      * - slice end offsets (gotten from the slice lengths)
      */
     for (i = 0; i < 256; i++) {
         bytestream2_put_byte(pb, lengths[i]);
 
         he[i].len = lengths[i];
         he[i].sym = i;
     }
 
     /* Calculate the huffman codes themselves */
     calculate_codes(he);
 
     send = 0;
     for (i = 0; i < c->slices; i++) {
         sstart  = send;

         send    = height * (i + 1) / c->slices & cmask;

 
         /*
          * Write the huffman codes to a buffer,
          * get the offset in bits and convert to bytes.
          */
         offset += write_huff_codes(dst + sstart * width, c->slice_bits,

                                    width * height + 4, width,

                                    send - sstart, he) >> 3;
 
         slice_len = offset - slice_len;
 
         /* Byteswap the written huffman codes */

         c->bdsp.bswap_buf((uint32_t *) c->slice_bits,
                           (uint32_t *) c->slice_bits,
                           slice_len >> 2);

 
         /* Write the offset to the stream */
         bytestream2_put_le32(pb, offset);
 
         /* Seek to the data part of the packet */
         bytestream2_seek_p(pb, 4 * (c->slices - i - 1) +
                            offset - slice_len, SEEK_CUR);
 
         /* Write the slices' data into the output packet */
         bytestream2_put_buffer(pb, c->slice_bits, slice_len);
 
         /* Seek back to the slice offsets */
         bytestream2_seek_p(pb, -4 * (c->slices - i - 1) - offset,
                            SEEK_CUR);
 
         slice_len = offset;
     }
 
     /* And at the end seek to the end of written slice(s) */
     bytestream2_seek_p(pb, offset, SEEK_CUR);
 
     return 0;
 }
 
 static int utvideo_encode_frame(AVCodecContext *avctx, AVPacket *pkt,
                                 const AVFrame *pic, int *got_packet)
 {
     UtvideoContext *c = avctx->priv_data;
     PutByteContext pb;
 
     uint32_t frame_info;
 
     uint8_t *dst;
 
     int width = avctx->width, height = avctx->height;
     int i, ret = 0;
 
     /* Allocate a new packet if needed, and set it to the pointer dst */

     ret = ff_alloc_packet2(avctx, pkt, (256 + 4 * c->slices + width * height) *

                            c->planes + 4, 0);

     if (ret < 0)

         return ret;
 
     dst = pkt->data;
 
     bytestream2_init_writer(&pb, dst, pkt->size);
 

     av_fast_padded_malloc(&c->slice_bits, &c->slice_bits_size, width * height + 4);

 
     if (!c->slice_bits) {
         av_log(avctx, AV_LOG_ERROR, "Cannot allocate temporary buffer 2.\n");
         return AVERROR(ENOMEM);
     }
 
     /* In case of RGB, mangle the planes to Ut Video's format */

     if (avctx->pix_fmt == AV_PIX_FMT_RGBA || avctx->pix_fmt == AV_PIX_FMT_RGB24)

         mangle_rgb_planes(c->slice_buffer, c->slice_stride, pic->data[0],
                           c->planes, pic->linesize[0], width, height);

 
     /* Deal with the planes */
     switch (avctx->pix_fmt) {

     case AV_PIX_FMT_RGB24:
     case AV_PIX_FMT_RGBA:

         for (i = 0; i < c->planes; i++) {

             ret = encode_plane(avctx, c->slice_buffer[i] + 2 * c->slice_stride,

                                c->slice_buffer[i], c->slice_stride, i,

                                width, height, &pb);
 
             if (ret) {
                 av_log(avctx, AV_LOG_ERROR, "Error encoding plane %d.\n", i);
                 return ret;
             }
         }
         break;

     case AV_PIX_FMT_YUV444P:
         for (i = 0; i < c->planes; i++) {
             ret = encode_plane(avctx, pic->data[i], c->slice_buffer[0],
                                pic->linesize[i], i, width, height, &pb);
 
             if (ret) {
                 av_log(avctx, AV_LOG_ERROR, "Error encoding plane %d.\n", i);
                 return ret;
             }
         }
         break;

     case AV_PIX_FMT_YUV422P:

         for (i = 0; i < c->planes; i++) {

             ret = encode_plane(avctx, pic->data[i], c->slice_buffer[0],

                                pic->linesize[i], i, width >> !!i, height, &pb);

 
             if (ret) {
                 av_log(avctx, AV_LOG_ERROR, "Error encoding plane %d.\n", i);
                 return ret;
             }
         }
         break;

     case AV_PIX_FMT_YUV420P:

         for (i = 0; i < c->planes; i++) {

             ret = encode_plane(avctx, pic->data[i], c->slice_buffer[0],

                                pic->linesize[i], i, width >> !!i, height >> !!i,

                                &pb);
 
             if (ret) {
                 av_log(avctx, AV_LOG_ERROR, "Error encoding plane %d.\n", i);
                 return ret;
             }
         }
         break;
     default:
         av_log(avctx, AV_LOG_ERROR, "Unknown pixel format: %d\n",
                avctx->pix_fmt);
         return AVERROR_INVALIDDATA;
     }
 
     /*

      * Write frame information (LE 32-bit unsigned)

      * into the output packet.
      * Contains the prediction method.
      */
     frame_info = c->frame_pred << 8;
     bytestream2_put_le32(&pb, frame_info);
 
     /*
      * At least currently Ut Video is IDR only.
      * Set flags accordingly.
      */

 #if FF_API_CODED_FRAME
 FF_DISABLE_DEPRECATION_WARNINGS

     avctx->coded_frame->key_frame = 1;
     avctx->coded_frame->pict_type = AV_PICTURE_TYPE_I;

 FF_ENABLE_DEPRECATION_WARNINGS
 #endif

 
     pkt->size   = bytestream2_tell_p(&pb);
     pkt->flags |= AV_PKT_FLAG_KEY;
 
     /* Packet should be done */
     *got_packet = 1;
 
     return 0;
 }
 

 #define OFFSET(x) offsetof(UtvideoContext, x)
 #define VE AV_OPT_FLAG_VIDEO_PARAM | AV_OPT_FLAG_ENCODING_PARAM
 static const AVOption options[] = {
 { "pred", "Prediction method", OFFSET(frame_pred), AV_OPT_TYPE_INT, { .i64 = PRED_LEFT }, PRED_NONE, PRED_MEDIAN, VE, "pred" },
     { "none",     NULL, 0, AV_OPT_TYPE_CONST, { .i64 = PRED_NONE }, INT_MIN, INT_MAX, VE, "pred" },
     { "left",     NULL, 0, AV_OPT_TYPE_CONST, { .i64 = PRED_LEFT }, INT_MIN, INT_MAX, VE, "pred" },
     { "gradient", NULL, 0, AV_OPT_TYPE_CONST, { .i64 = PRED_GRADIENT }, INT_MIN, INT_MAX, VE, "pred" },
     { "median",   NULL, 0, AV_OPT_TYPE_CONST, { .i64 = PRED_MEDIAN }, INT_MIN, INT_MAX, VE, "pred" },
 
     { NULL},
 };
 
 static const AVClass utvideo_class = {
     .class_name = "utvideo",
     .item_name  = av_default_item_name,
     .option     = options,
     .version    = LIBAVUTIL_VERSION_INT,
 };
 

 AVCodec ff_utvideo_encoder = {
     .name           = "utvideo",

     .long_name      = NULL_IF_CONFIG_SMALL("Ut Video"),

     .type           = AVMEDIA_TYPE_VIDEO,

     .id             = AV_CODEC_ID_UTVIDEO,

     .priv_data_size = sizeof(UtvideoContext),

     .priv_class     = &utvideo_class,

     .init           = utvideo_encode_init,
     .encode2        = utvideo_encode_frame,
     .close          = utvideo_encode_close,

     .capabilities   = AV_CODEC_CAP_FRAME_THREADS | AV_CODEC_CAP_INTRA_ONLY,

     .pix_fmts       = (const enum AVPixelFormat[]) {
                           AV_PIX_FMT_RGB24, AV_PIX_FMT_RGBA, AV_PIX_FMT_YUV422P,

                           AV_PIX_FMT_YUV420P, AV_PIX_FMT_YUV444P, AV_PIX_FMT_NONE

                       },
 };