libavcodec/escape130.c - third_party/ffmpeg - Git at Google

 /*
  * Escape 130 Video Decoder
  * Copyright (C) 2008 Eli Friedman (eli.friedman <at> 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 "avcodec.h"

 #define BITSTREAM_READER_LE
 #include "get_bits.h"

 typedef struct Escape130Context {
     AVFrame frame;
     uint8_t *bases;
 } Escape130Context;

 /**
  * Initialize the decoder
  * @param avctx decoder context
  * @return 0 success, negative on error
  */
 static av_cold int escape130_decode_init(AVCodecContext *avctx)
 {
     Escape130Context *s = avctx->priv_data;
     avctx->pix_fmt = PIX_FMT_YUV420P;

     if((avctx->width&1) || (avctx->height&1)){
         av_log(avctx, AV_LOG_ERROR, "Dimensions are not a multiple of the block size\n");
         return AVERROR(EINVAL);
     }

     s->bases= av_malloc(avctx->width * avctx->height /4);

     return 0;
 }

 static av_cold int escape130_decode_close(AVCodecContext *avctx)
 {
     Escape130Context *s = avctx->priv_data;

     if (s->frame.data[0])
         avctx->release_buffer(avctx, &s->frame);

     av_freep(&s->bases);

     return 0;
 }

 static unsigned decode_skip_count(GetBitContext* gb) {
     unsigned value;
     // This function reads a maximum of 27 bits,
     // which is within the padding space
     if (get_bits_left(gb) < 1+3)
         return -1;

     value = get_bits1(gb);
     if (value)
         return 0;

     value = get_bits(gb, 3);
     if (value)
         return value;

     value = get_bits(gb, 8);
     if (value)
         return value + 7;

     value = get_bits(gb, 15);
     if (value)
         return value + 262;

     return -1;
 }

 /**
  * Decode a single frame
  * @param avctx decoder context
  * @param data decoded frame
  * @param data_size size of the decoded frame
  * @param buf input buffer
  * @param buf_size input buffer size
  * @return 0 success, -1 on error
  */
 static int escape130_decode_frame(AVCodecContext *avctx,
                                   void *data, int *data_size,
                                   AVPacket *avpkt)
 {
     const uint8_t *buf = avpkt->data;
     int buf_size = avpkt->size;
     Escape130Context *s = avctx->priv_data;

     GetBitContext gb;
     unsigned i;

     uint8_t *old_y, *old_cb, *old_cr,
             *new_y, *new_cb, *new_cr;
     unsigned old_y_stride, old_cb_stride, old_cr_stride,
              new_y_stride, new_cb_stride, new_cr_stride;
     unsigned total_blocks = avctx->width * avctx->height / 4,
              block_index, row_index = 0;
     unsigned y[4] = {0}, cb = 16, cr = 16;
     unsigned skip = -1;
     unsigned y_base = 0;
     uint8_t *yb= s->bases;

     AVFrame new_frame = { { 0 } };

     init_get_bits(&gb, buf, buf_size * 8);

     if (get_bits_left(&gb) < 128)
         return -1;

     // Header; no useful information in here
     skip_bits_long(&gb, 128);

     new_frame.reference = 3;
     if (avctx->get_buffer(avctx, &new_frame)) {
         av_log(avctx, AV_LOG_ERROR, "get_buffer() failed\n");
         return -1;
     }

     new_y = new_frame.data[0];
     new_cb = new_frame.data[1];
     new_cr = new_frame.data[2];
     new_y_stride = new_frame.linesize[0];
     new_cb_stride = new_frame.linesize[1];
     new_cr_stride = new_frame.linesize[2];
     old_y = s->frame.data[0];
     old_cb = s->frame.data[1];
     old_cr = s->frame.data[2];
     old_y_stride = s->frame.linesize[0];
     old_cb_stride = s->frame.linesize[1];
     old_cr_stride = s->frame.linesize[2];

     av_log(avctx, AV_LOG_DEBUG,
            "Strides: %i, %i\n",
            new_y_stride, new_cb_stride);

     for (block_index = 0; block_index < total_blocks; block_index++) {
         // Note that this call will make us skip the rest of the blocks
         // if the frame prematurely ends
         if (skip == -1)
             skip = decode_skip_count(&gb);

         if (skip) {
             if (old_y) {
                 y[0] = old_y[0] / 4;
                 y[1] = old_y[1] / 4;
                 y[2] = old_y[old_y_stride] / 4;
                 y[3] = old_y[old_y_stride+1] / 4;
                 y_base= yb[0];
                 cb = old_cb[0] / 8;
                 cr = old_cr[0] / 8;
             } else {
                 y_base=y[0] = y[1] = y[2] = y[3] = 0;
                 cb = cr = 16;
             }
         } else {
             if (get_bits1(&gb)) {
                 static const uint8_t offset_table[] = {2, 4, 10, 20};
                 static const int8_t sign_table[64][4] =
                     { {0, 0, 0, 0},
                       {-1, 1, 0, 0},
                       {1, -1, 0, 0},
                       {-1, 0, 1, 0},
                       {-1, 1, 1, 0},
                       {0, -1, 1, 0},
                       {1, -1, 1, 0},
                       {-1, -1, 1, 0},
                       {1, 0, -1, 0},
                       {0, 1, -1, 0},
                       {1, 1, -1, 0},
                       {-1, 1, -1, 0},
                       {1, -1, -1, 0},
                       {-1, 0, 0, 1},
                       {-1, 1, 0, 1},
                       {0, -1, 0, 1},

                       {0, 0, 0, 0},
                       {1, -1, 0, 1},
                       {-1, -1, 0, 1},
                       {-1, 0, 1, 1},
                       {-1, 1, 1, 1},
                       {0, -1, 1, 1},
                       {1, -1, 1, 1},
                       {-1, -1, 1, 1},
                       {0, 0, -1, 1},
                       {1, 0, -1, 1},
                       {-1, 0, -1, 1},
                       {0, 1, -1, 1},
                       {1, 1, -1, 1},
                       {-1, 1, -1, 1},
                       {0, -1, -1, 1},
                       {1, -1, -1, 1},

                       {0, 0, 0, 0},
                       {-1, -1, -1, 1},
                       {1, 0, 0, -1},
                       {0, 1, 0, -1},
                       {1, 1, 0, -1},
                       {-1, 1, 0, -1},
                       {1, -1, 0, -1},
                       {0, 0, 1, -1},
                       {1, 0, 1, -1},
                       {-1, 0, 1, -1},
                       {0, 1, 1, -1},
                       {1, 1, 1, -1},
                       {-1, 1, 1, -1},
                       {0, -1, 1, -1},
                       {1, -1, 1, -1},
                       {-1, -1, 1, -1},

                       {0, 0, 0, 0},
                       {1, 0, -1, -1},
                       {0, 1, -1, -1},
                       {1, 1, -1, -1},
                       {-1, 1, -1, -1},
                       {1, -1, -1, -1} };
                 unsigned sign_selector = get_bits(&gb, 6);
                 unsigned difference_selector = get_bits(&gb, 2);
                 y_base = 2 * get_bits(&gb, 5);
                 for (i = 0; i < 4; i++) {
                     y[i] = av_clip((int)y_base + offset_table[difference_selector] *
                                             sign_table[sign_selector][i], 0, 63);
                 }
             } else if (get_bits1(&gb)) {
                 if (get_bits1(&gb)) {
                     y_base = get_bits(&gb, 6);
                 } else {
                     unsigned adjust_index = get_bits(&gb, 3);
                     static const int8_t adjust[] = {-4, -3, -2, -1, 1, 2, 3, 4};
                     y_base = (y_base + adjust[adjust_index]) & 63;
                 }
                 for (i = 0; i < 4; i++)
                     y[i] = y_base;
             }

             if (get_bits1(&gb)) {
                 if (get_bits1(&gb)) {
                     cb = get_bits(&gb, 5);
                     cr = get_bits(&gb, 5);
                 } else {
                     unsigned adjust_index = get_bits(&gb, 3);
                     static const int8_t adjust[2][8] =
                         {  { 1, 1, 0, -1, -1, -1,  0,  1 },
                            { 0, 1, 1,  1,  0, -1, -1, -1 } };
                     cb = (cb + adjust[0][adjust_index]) & 31;
                     cr = (cr + adjust[1][adjust_index]) & 31;
                 }
             }
         }
         *yb++= y_base;

         new_y[0] = y[0] * 4;
         new_y[1] = y[1] * 4;
         new_y[new_y_stride] = y[2] * 4;
         new_y[new_y_stride + 1] = y[3] * 4;
         *new_cb = cb * 8;
         *new_cr = cr * 8;

         if (old_y)
             old_y += 2, old_cb++, old_cr++;
         new_y += 2, new_cb++, new_cr++;
         row_index++;
         if (avctx->width / 2 == row_index) {
             row_index = 0;
             if (old_y) {
                 old_y  += old_y_stride * 2  - avctx->width;
                 old_cb += old_cb_stride - avctx->width / 2;
                 old_cr += old_cr_stride - avctx->width / 2;
             }
             new_y  += new_y_stride * 2  - avctx->width;
             new_cb += new_cb_stride - avctx->width / 2;
             new_cr += new_cr_stride - avctx->width / 2;
         }

         skip--;
     }

     av_log(avctx, AV_LOG_DEBUG,
            "Escape sizes: %i, %i\n",
            buf_size, get_bits_count(&gb) / 8);

     if (s->frame.data[0])
         avctx->release_buffer(avctx, &s->frame);

     *(AVFrame*)data = s->frame = new_frame;
     *data_size = sizeof(AVFrame);

     return buf_size;
 }


 AVCodec ff_escape130_decoder = {
     .name           = "escape130",
     .type           = AVMEDIA_TYPE_VIDEO,
     .id             = CODEC_ID_ESCAPE130,
     .priv_data_size = sizeof(Escape130Context),
     .init           = escape130_decode_init,
     .close          = escape130_decode_close,
     .decode         = escape130_decode_frame,
     .capabilities   = CODEC_CAP_DR1,
     .long_name = NULL_IF_CONFIG_SMALL("Escape 130"),
 };
	/*
	* Escape 130 Video Decoder
	* Copyright (C) 2008 Eli Friedman (eli.friedman <at> 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 "avcodec.h"

	#define BITSTREAM_READER_LE
	#include "get_bits.h"

	typedef struct Escape130Context {
	AVFrame frame;
	uint8_t *bases;
	} Escape130Context;

	/**
	* Initialize the decoder
	* @param avctx decoder context
	* @return 0 success, negative on error
	*/
	static av_cold int escape130_decode_init(AVCodecContext *avctx)
	{
	Escape130Context *s = avctx->priv_data;
	avctx->pix_fmt = PIX_FMT_YUV420P;

	if((avctx->width&1) \|\| (avctx->height&1)){
	av_log(avctx, AV_LOG_ERROR, "Dimensions are not a multiple of the block size\n");
	return AVERROR(EINVAL);
	}

	s->bases= av_malloc(avctx->width * avctx->height /4);

	return 0;
	}

	static av_cold int escape130_decode_close(AVCodecContext *avctx)
	{
	Escape130Context *s = avctx->priv_data;

	if (s->frame.data[0])
	avctx->release_buffer(avctx, &s->frame);

	av_freep(&s->bases);

	return 0;
	}

	static unsigned decode_skip_count(GetBitContext* gb) {
	unsigned value;
	// This function reads a maximum of 27 bits,
	// which is within the padding space
	if (get_bits_left(gb) < 1+3)
	return -1;

	value = get_bits1(gb);
	if (value)
	return 0;

	value = get_bits(gb, 3);
	if (value)
	return value;

	value = get_bits(gb, 8);
	if (value)
	return value + 7;

	value = get_bits(gb, 15);
	if (value)
	return value + 262;

	return -1;
	}

	/**
	* Decode a single frame
	* @param avctx decoder context
	* @param data decoded frame
	* @param data_size size of the decoded frame
	* @param buf input buffer
	* @param buf_size input buffer size
	* @return 0 success, -1 on error
	*/
	static int escape130_decode_frame(AVCodecContext *avctx,
	void data, int data_size,
	AVPacket *avpkt)
	{
	const uint8_t *buf = avpkt->data;
	int buf_size = avpkt->size;
	Escape130Context *s = avctx->priv_data;

	GetBitContext gb;
	unsigned i;

	uint8_t old_y, old_cb, *old_cr,
	new_y, new_cb, *new_cr;
	unsigned old_y_stride, old_cb_stride, old_cr_stride,
	new_y_stride, new_cb_stride, new_cr_stride;
	unsigned total_blocks = avctx->width * avctx->height / 4,
	block_index, row_index = 0;
	unsigned y[4] = {0}, cb = 16, cr = 16;
	unsigned skip = -1;
	unsigned y_base = 0;
	uint8_t *yb= s->bases;

	AVFrame new_frame = { { 0 } };

	init_get_bits(&gb, buf, buf_size * 8);

	if (get_bits_left(&gb) < 128)
	return -1;

	// Header; no useful information in here
	skip_bits_long(&gb, 128);

	new_frame.reference = 3;
	if (avctx->get_buffer(avctx, &new_frame)) {
	av_log(avctx, AV_LOG_ERROR, "get_buffer() failed\n");
	return -1;
	}

	new_y = new_frame.data[0];
	new_cb = new_frame.data[1];
	new_cr = new_frame.data[2];
	new_y_stride = new_frame.linesize[0];
	new_cb_stride = new_frame.linesize[1];
	new_cr_stride = new_frame.linesize[2];
	old_y = s->frame.data[0];
	old_cb = s->frame.data[1];
	old_cr = s->frame.data[2];
	old_y_stride = s->frame.linesize[0];
	old_cb_stride = s->frame.linesize[1];
	old_cr_stride = s->frame.linesize[2];

	av_log(avctx, AV_LOG_DEBUG,
	"Strides: %i, %i\n",
	new_y_stride, new_cb_stride);

	for (block_index = 0; block_index < total_blocks; block_index++) {
	// Note that this call will make us skip the rest of the blocks
	// if the frame prematurely ends
	if (skip == -1)
	skip = decode_skip_count(&gb);

	if (skip) {
	if (old_y) {
	y[0] = old_y[0] / 4;
	y[1] = old_y[1] / 4;
	y[2] = old_y[old_y_stride] / 4;
	y[3] = old_y[old_y_stride+1] / 4;
	y_base= yb[0];
	cb = old_cb[0] / 8;
	cr = old_cr[0] / 8;
	} else {
	y_base=y[0] = y[1] = y[2] = y[3] = 0;
	cb = cr = 16;
	}
	} else {
	if (get_bits1(&gb)) {
	static const uint8_t offset_table[] = {2, 4, 10, 20};
	static const int8_t sign_table[64][4] =
	{ {0, 0, 0, 0},
	{-1, 1, 0, 0},
	{1, -1, 0, 0},
	{-1, 0, 1, 0},
	{-1, 1, 1, 0},
	{0, -1, 1, 0},
	{1, -1, 1, 0},
	{-1, -1, 1, 0},
	{1, 0, -1, 0},
	{0, 1, -1, 0},
	{1, 1, -1, 0},
	{-1, 1, -1, 0},
	{1, -1, -1, 0},
	{-1, 0, 0, 1},
	{-1, 1, 0, 1},
	{0, -1, 0, 1},

	{0, 0, 0, 0},
	{1, -1, 0, 1},
	{-1, -1, 0, 1},
	{-1, 0, 1, 1},
	{-1, 1, 1, 1},
	{0, -1, 1, 1},
	{1, -1, 1, 1},
	{-1, -1, 1, 1},
	{0, 0, -1, 1},
	{1, 0, -1, 1},
	{-1, 0, -1, 1},
	{0, 1, -1, 1},
	{1, 1, -1, 1},
	{-1, 1, -1, 1},
	{0, -1, -1, 1},
	{1, -1, -1, 1},

	{0, 0, 0, 0},
	{-1, -1, -1, 1},
	{1, 0, 0, -1},
	{0, 1, 0, -1},
	{1, 1, 0, -1},
	{-1, 1, 0, -1},
	{1, -1, 0, -1},
	{0, 0, 1, -1},
	{1, 0, 1, -1},
	{-1, 0, 1, -1},
	{0, 1, 1, -1},
	{1, 1, 1, -1},
	{-1, 1, 1, -1},
	{0, -1, 1, -1},
	{1, -1, 1, -1},
	{-1, -1, 1, -1},

	{0, 0, 0, 0},
	{1, 0, -1, -1},
	{0, 1, -1, -1},
	{1, 1, -1, -1},
	{-1, 1, -1, -1},
	{1, -1, -1, -1} };
	unsigned sign_selector = get_bits(&gb, 6);
	unsigned difference_selector = get_bits(&gb, 2);
	y_base = 2 * get_bits(&gb, 5);
	for (i = 0; i < 4; i++) {
	y[i] = av_clip((int)y_base + offset_table[difference_selector] *
	sign_table[sign_selector][i], 0, 63);
	}
	} else if (get_bits1(&gb)) {
	if (get_bits1(&gb)) {
	y_base = get_bits(&gb, 6);
	} else {
	unsigned adjust_index = get_bits(&gb, 3);
	static const int8_t adjust[] = {-4, -3, -2, -1, 1, 2, 3, 4};
	y_base = (y_base + adjust[adjust_index]) & 63;
	}
	for (i = 0; i < 4; i++)
	y[i] = y_base;
	}

	if (get_bits1(&gb)) {
	if (get_bits1(&gb)) {
	cb = get_bits(&gb, 5);
	cr = get_bits(&gb, 5);
	} else {
	unsigned adjust_index = get_bits(&gb, 3);
	static const int8_t adjust[2][8] =
	{ { 1, 1, 0, -1, -1, -1, 0, 1 },
	{ 0, 1, 1, 1, 0, -1, -1, -1 } };
	cb = (cb + adjust[0][adjust_index]) & 31;
	cr = (cr + adjust[1][adjust_index]) & 31;
	}
	}
	}
	*yb++= y_base;

	new_y[0] = y[0] * 4;
	new_y[1] = y[1] * 4;
	new_y[new_y_stride] = y[2] * 4;
	new_y[new_y_stride + 1] = y[3] * 4;
	new_cb = cb 8;
	new_cr = cr 8;

	if (old_y)
	old_y += 2, old_cb++, old_cr++;
	new_y += 2, new_cb++, new_cr++;
	row_index++;
	if (avctx->width / 2 == row_index) {
	row_index = 0;
	if (old_y) {
	old_y += old_y_stride * 2 - avctx->width;
	old_cb += old_cb_stride - avctx->width / 2;
	old_cr += old_cr_stride - avctx->width / 2;
	}
	new_y += new_y_stride * 2 - avctx->width;
	new_cb += new_cb_stride - avctx->width / 2;
	new_cr += new_cr_stride - avctx->width / 2;
	}

	skip--;
	}

	av_log(avctx, AV_LOG_DEBUG,
	"Escape sizes: %i, %i\n",
	buf_size, get_bits_count(&gb) / 8);

	if (s->frame.data[0])
	avctx->release_buffer(avctx, &s->frame);

	(AVFrame)data = s->frame = new_frame;
	*data_size = sizeof(AVFrame);

	return buf_size;
	}


	AVCodec ff_escape130_decoder = {
	.name = "escape130",
	.type = AVMEDIA_TYPE_VIDEO,
	.id = CODEC_ID_ESCAPE130,
	.priv_data_size = sizeof(Escape130Context),
	.init = escape130_decode_init,
	.close = escape130_decode_close,
	.decode = escape130_decode_frame,
	.capabilities = CODEC_CAP_DR1,
	.long_name = NULL_IF_CONFIG_SMALL("Escape 130"),
	};