yading@10: /*
yading@10:  * Escape 130 Video Decoder
yading@10:  * Copyright (C) 2008 Eli Friedman (eli.friedman <at> gmail.com)
yading@10:  *
yading@10:  * This file is part of FFmpeg.
yading@10:  *
yading@10:  * FFmpeg is free software; you can redistribute it and/or
yading@10:  * modify it under the terms of the GNU Lesser General Public
yading@10:  * License as published by the Free Software Foundation; either
yading@10:  * version 2.1 of the License, or (at your option) any later version.
yading@10:  *
yading@10:  * FFmpeg is distributed in the hope that it will be useful,
yading@10:  * but WITHOUT ANY WARRANTY; without even the implied warranty of
yading@10:  * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
yading@10:  * Lesser General Public License for more details.
yading@10:  *
yading@10:  * You should have received a copy of the GNU Lesser General Public
yading@10:  * License along with FFmpeg; if not, write to the Free Software
yading@10:  * Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA
yading@10:  */
yading@10: 
yading@10: #include "avcodec.h"
yading@10: 
yading@10: #define BITSTREAM_READER_LE
yading@10: #include "get_bits.h"
yading@10: #include "internal.h"
yading@10: 
yading@10: 
yading@10: typedef struct Escape130Context {
yading@10:     AVFrame frame;
yading@10:     uint8_t *bases;
yading@10: } Escape130Context;
yading@10: 
yading@10: /**
yading@10:  * Initialize the decoder
yading@10:  * @param avctx decoder context
yading@10:  * @return 0 success, negative on error
yading@10:  */
yading@10: static av_cold int escape130_decode_init(AVCodecContext *avctx)
yading@10: {
yading@10:     Escape130Context *s = avctx->priv_data;
yading@10:     avctx->pix_fmt = AV_PIX_FMT_YUV420P;
yading@10:     avcodec_get_frame_defaults(&s->frame);
yading@10: 
yading@10:     if((avctx->width&1) || (avctx->height&1)){
yading@10:         av_log(avctx, AV_LOG_ERROR, "Dimensions are not a multiple of the block size\n");
yading@10:         return AVERROR(EINVAL);
yading@10:     }
yading@10: 
yading@10:     s->bases= av_malloc(avctx->width * avctx->height /4);
yading@10: 
yading@10:     return 0;
yading@10: }
yading@10: 
yading@10: static av_cold int escape130_decode_close(AVCodecContext *avctx)
yading@10: {
yading@10:     Escape130Context *s = avctx->priv_data;
yading@10: 
yading@10:     av_frame_unref(&s->frame);
yading@10: 
yading@10:     av_freep(&s->bases);
yading@10: 
yading@10:     return 0;
yading@10: }
yading@10: 
yading@10: static unsigned decode_skip_count(GetBitContext* gb) {
yading@10:     unsigned value;
yading@10:     // This function reads a maximum of 27 bits,
yading@10:     // which is within the padding space
yading@10:     if (get_bits_left(gb) < 1+3)
yading@10:         return -1;
yading@10: 
yading@10:     value = get_bits1(gb);
yading@10:     if (value)
yading@10:         return 0;
yading@10: 
yading@10:     value = get_bits(gb, 3);
yading@10:     if (value)
yading@10:         return value;
yading@10: 
yading@10:     value = get_bits(gb, 8);
yading@10:     if (value)
yading@10:         return value + 7;
yading@10: 
yading@10:     value = get_bits(gb, 15);
yading@10:     if (value)
yading@10:         return value + 262;
yading@10: 
yading@10:     return -1;
yading@10: }
yading@10: 
yading@10: /**
yading@10:  * Decode a single frame
yading@10:  * @param avctx decoder context
yading@10:  * @param data decoded frame
yading@10:  * @param got_frame have decoded frame
yading@10:  * @param buf input buffer
yading@10:  * @param buf_size input buffer size
yading@10:  * @return 0 success, -1 on error
yading@10:  */
yading@10: static int escape130_decode_frame(AVCodecContext *avctx,
yading@10:                                   void *data, int *got_frame,
yading@10:                                   AVPacket *avpkt)
yading@10: {
yading@10:     const uint8_t *buf = avpkt->data;
yading@10:     int buf_size = avpkt->size;
yading@10:     Escape130Context *s = avctx->priv_data;
yading@10: 
yading@10:     GetBitContext gb;
yading@10:     unsigned i;
yading@10:     int ret;
yading@10: 
yading@10:     uint8_t *old_y, *old_cb, *old_cr,
yading@10:             *new_y, *new_cb, *new_cr;
yading@10:     unsigned old_y_stride, old_cb_stride, old_cr_stride,
yading@10:              new_y_stride, new_cb_stride, new_cr_stride;
yading@10:     unsigned total_blocks = avctx->width * avctx->height / 4,
yading@10:              block_index, row_index = 0;
yading@10:     unsigned y[4] = {0}, cb = 16, cr = 16;
yading@10:     unsigned skip = -1;
yading@10:     unsigned y_base = 0;
yading@10:     uint8_t *yb= s->bases;
yading@10: 
yading@10:     AVFrame *frame = data;
yading@10: 
yading@10:     init_get_bits(&gb, buf, buf_size * 8);
yading@10: 
yading@10:     if (get_bits_left(&gb) < 128)
yading@10:         return -1;
yading@10: 
yading@10:     // Header; no useful information in here
yading@10:     skip_bits_long(&gb, 128);
yading@10: 
yading@10:     if ((ret = ff_get_buffer(avctx, frame, AV_GET_BUFFER_FLAG_REF)) < 0)
yading@10:         return ret;
yading@10: 
yading@10:     new_y = frame->data[0];
yading@10:     new_cb = frame->data[1];
yading@10:     new_cr = frame->data[2];
yading@10:     new_y_stride = frame->linesize[0];
yading@10:     new_cb_stride = frame->linesize[1];
yading@10:     new_cr_stride = frame->linesize[2];
yading@10:     old_y = s->frame.data[0];
yading@10:     old_cb = s->frame.data[1];
yading@10:     old_cr = s->frame.data[2];
yading@10:     old_y_stride = s->frame.linesize[0];
yading@10:     old_cb_stride = s->frame.linesize[1];
yading@10:     old_cr_stride = s->frame.linesize[2];
yading@10: 
yading@10:     av_log(avctx, AV_LOG_DEBUG,
yading@10:            "Strides: %i, %i\n",
yading@10:            new_y_stride, new_cb_stride);
yading@10: 
yading@10:     for (block_index = 0; block_index < total_blocks; block_index++) {
yading@10:         // Note that this call will make us skip the rest of the blocks
yading@10:         // if the frame prematurely ends
yading@10:         if (skip == -1)
yading@10:             skip = decode_skip_count(&gb);
yading@10: 
yading@10:         if (skip) {
yading@10:             if (old_y) {
yading@10:                 y[0] = old_y[0] / 4;
yading@10:                 y[1] = old_y[1] / 4;
yading@10:                 y[2] = old_y[old_y_stride] / 4;
yading@10:                 y[3] = old_y[old_y_stride+1] / 4;
yading@10:                 y_base= yb[0];
yading@10:                 cb = old_cb[0] / 8;
yading@10:                 cr = old_cr[0] / 8;
yading@10:             } else {
yading@10:                 y_base=y[0] = y[1] = y[2] = y[3] = 0;
yading@10:                 cb = cr = 16;
yading@10:             }
yading@10:         } else {
yading@10:             if (get_bits1(&gb)) {
yading@10:                 static const uint8_t offset_table[] = {2, 4, 10, 20};
yading@10:                 static const int8_t sign_table[64][4] =
yading@10:                     { {0, 0, 0, 0},
yading@10:                       {-1, 1, 0, 0},
yading@10:                       {1, -1, 0, 0},
yading@10:                       {-1, 0, 1, 0},
yading@10:                       {-1, 1, 1, 0},
yading@10:                       {0, -1, 1, 0},
yading@10:                       {1, -1, 1, 0},
yading@10:                       {-1, -1, 1, 0},
yading@10:                       {1, 0, -1, 0},
yading@10:                       {0, 1, -1, 0},
yading@10:                       {1, 1, -1, 0},
yading@10:                       {-1, 1, -1, 0},
yading@10:                       {1, -1, -1, 0},
yading@10:                       {-1, 0, 0, 1},
yading@10:                       {-1, 1, 0, 1},
yading@10:                       {0, -1, 0, 1},
yading@10: 
yading@10:                       {0, 0, 0, 0},
yading@10:                       {1, -1, 0, 1},
yading@10:                       {-1, -1, 0, 1},
yading@10:                       {-1, 0, 1, 1},
yading@10:                       {-1, 1, 1, 1},
yading@10:                       {0, -1, 1, 1},
yading@10:                       {1, -1, 1, 1},
yading@10:                       {-1, -1, 1, 1},
yading@10:                       {0, 0, -1, 1},
yading@10:                       {1, 0, -1, 1},
yading@10:                       {-1, 0, -1, 1},
yading@10:                       {0, 1, -1, 1},
yading@10:                       {1, 1, -1, 1},
yading@10:                       {-1, 1, -1, 1},
yading@10:                       {0, -1, -1, 1},
yading@10:                       {1, -1, -1, 1},
yading@10: 
yading@10:                       {0, 0, 0, 0},
yading@10:                       {-1, -1, -1, 1},
yading@10:                       {1, 0, 0, -1},
yading@10:                       {0, 1, 0, -1},
yading@10:                       {1, 1, 0, -1},
yading@10:                       {-1, 1, 0, -1},
yading@10:                       {1, -1, 0, -1},
yading@10:                       {0, 0, 1, -1},
yading@10:                       {1, 0, 1, -1},
yading@10:                       {-1, 0, 1, -1},
yading@10:                       {0, 1, 1, -1},
yading@10:                       {1, 1, 1, -1},
yading@10:                       {-1, 1, 1, -1},
yading@10:                       {0, -1, 1, -1},
yading@10:                       {1, -1, 1, -1},
yading@10:                       {-1, -1, 1, -1},
yading@10: 
yading@10:                       {0, 0, 0, 0},
yading@10:                       {1, 0, -1, -1},
yading@10:                       {0, 1, -1, -1},
yading@10:                       {1, 1, -1, -1},
yading@10:                       {-1, 1, -1, -1},
yading@10:                       {1, -1, -1, -1} };
yading@10:                 unsigned sign_selector = get_bits(&gb, 6);
yading@10:                 unsigned difference_selector = get_bits(&gb, 2);
yading@10:                 y_base = 2 * get_bits(&gb, 5);
yading@10:                 for (i = 0; i < 4; i++) {
yading@10:                     y[i] = av_clip((int)y_base + offset_table[difference_selector] *
yading@10:                                             sign_table[sign_selector][i], 0, 63);
yading@10:                 }
yading@10:             } else if (get_bits1(&gb)) {
yading@10:                 if (get_bits1(&gb)) {
yading@10:                     y_base = get_bits(&gb, 6);
yading@10:                 } else {
yading@10:                     unsigned adjust_index = get_bits(&gb, 3);
yading@10:                     static const int8_t adjust[] = {-4, -3, -2, -1, 1, 2, 3, 4};
yading@10:                     y_base = (y_base + adjust[adjust_index]) & 63;
yading@10:                 }
yading@10:                 for (i = 0; i < 4; i++)
yading@10:                     y[i] = y_base;
yading@10:             }
yading@10: 
yading@10:             if (get_bits1(&gb)) {
yading@10:                 if (get_bits1(&gb)) {
yading@10:                     cb = get_bits(&gb, 5);
yading@10:                     cr = get_bits(&gb, 5);
yading@10:                 } else {
yading@10:                     unsigned adjust_index = get_bits(&gb, 3);
yading@10:                     static const int8_t adjust[2][8] =
yading@10:                         {  { 1, 1, 0, -1, -1, -1,  0,  1 },
yading@10:                            { 0, 1, 1,  1,  0, -1, -1, -1 } };
yading@10:                     cb = (cb + adjust[0][adjust_index]) & 31;
yading@10:                     cr = (cr + adjust[1][adjust_index]) & 31;
yading@10:                 }
yading@10:             }
yading@10:         }
yading@10:         *yb++= y_base;
yading@10: 
yading@10:         new_y[0] = y[0] * 4;
yading@10:         new_y[1] = y[1] * 4;
yading@10:         new_y[new_y_stride] = y[2] * 4;
yading@10:         new_y[new_y_stride + 1] = y[3] * 4;
yading@10:         *new_cb = cb * 8;
yading@10:         *new_cr = cr * 8;
yading@10: 
yading@10:         if (old_y)
yading@10:             old_y += 2, old_cb++, old_cr++;
yading@10:         new_y += 2, new_cb++, new_cr++;
yading@10:         row_index++;
yading@10:         if (avctx->width / 2 == row_index) {
yading@10:             row_index = 0;
yading@10:             if (old_y) {
yading@10:                 old_y  += old_y_stride * 2  - avctx->width;
yading@10:                 old_cb += old_cb_stride - avctx->width / 2;
yading@10:                 old_cr += old_cr_stride - avctx->width / 2;
yading@10:             }
yading@10:             new_y  += new_y_stride * 2  - avctx->width;
yading@10:             new_cb += new_cb_stride - avctx->width / 2;
yading@10:             new_cr += new_cr_stride - avctx->width / 2;
yading@10:         }
yading@10: 
yading@10:         skip--;
yading@10:     }
yading@10: 
yading@10:     av_log(avctx, AV_LOG_DEBUG,
yading@10:            "Escape sizes: %i, %i\n",
yading@10:            buf_size, get_bits_count(&gb) / 8);
yading@10: 
yading@10:     av_frame_unref(&s->frame);
yading@10:     if ((ret = av_frame_ref(&s->frame, frame)) < 0)
yading@10:         return ret;
yading@10: 
yading@10:     *got_frame = 1;
yading@10: 
yading@10:     return buf_size;
yading@10: }
yading@10: 
yading@10: 
yading@10: AVCodec ff_escape130_decoder = {
yading@10:     .name           = "escape130",
yading@10:     .type           = AVMEDIA_TYPE_VIDEO,
yading@10:     .id             = AV_CODEC_ID_ESCAPE130,
yading@10:     .priv_data_size = sizeof(Escape130Context),
yading@10:     .init           = escape130_decode_init,
yading@10:     .close          = escape130_decode_close,
yading@10:     .decode         = escape130_decode_frame,
yading@10:     .capabilities   = CODEC_CAP_DR1,
yading@10:     .long_name      = NULL_IF_CONFIG_SMALL("Escape 130"),
yading@10: };