libavcodec/notchlc.c - manifest_repos/ffmpeg - Git at Google

 /*
  * NotchLC decoder
  * Copyright (c) 2020 Paul B Mahol
  *
  * 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 <stdio.h>
 #include <stdlib.h>
 #include <string.h>

 #define BITSTREAM_READER_LE
 #include "libavutil/intreadwrite.h"
 #include "avcodec.h"
 #include "bytestream.h"
 #include "get_bits.h"
 #include "internal.h"
 #include "lzf.h"
 #include "thread.h"

 typedef struct NotchLCContext {
     unsigned compressed_size;
     unsigned format;

     uint8_t *uncompressed_buffer;
     unsigned uncompressed_size;

     uint8_t *lzf_buffer;
     int64_t lzf_size;

     unsigned texture_size_x;
     unsigned texture_size_y;
     unsigned y_data_row_offsets;
     unsigned uv_offset_data_offset;
     unsigned y_control_data_offset;
     unsigned a_control_word_offset;
     unsigned y_data_offset;
     unsigned uv_data_offset;
     unsigned y_data_size;
     unsigned a_data_offset;
     unsigned uv_count_offset;
     unsigned a_count_size;
     unsigned data_end;

     GetByteContext gb;
     PutByteContext pb;
 } NotchLCContext;

 static av_cold int decode_init(AVCodecContext *avctx)
 {
     avctx->pix_fmt = AV_PIX_FMT_YUVA444P12;
     avctx->color_range = AVCOL_RANGE_JPEG;
     avctx->colorspace = AVCOL_SPC_RGB;
     avctx->color_primaries = AVCOL_PRI_BT709;
     avctx->color_trc = AVCOL_TRC_IEC61966_2_1;

     return 0;
 }

 #define HISTORY_SIZE (64 * 1024)

 static int lz4_decompress(AVCodecContext *avctx,
                           GetByteContext *gb,
                           PutByteContext *pb)
 {
     unsigned reference_pos, match_length, delta, pos = 0;
     uint8_t history[64 * 1024];

     while (bytestream2_get_bytes_left(gb) > 0) {
         uint8_t token = bytestream2_get_byte(gb);
         unsigned num_literals = token >> 4;

         if (num_literals == 15) {
             unsigned char current;
             do {
                 current = bytestream2_get_byte(gb);
                 num_literals += current;
             } while (current == 255);
         }

         if (pos + num_literals < HISTORY_SIZE) {
             bytestream2_get_buffer(gb, history + pos, num_literals);
             pos += num_literals;
         } else {
             while (num_literals-- > 0) {
                 history[pos++] = bytestream2_get_byte(gb);
                 if (pos == HISTORY_SIZE) {
                     bytestream2_put_buffer(pb, history, HISTORY_SIZE);
                     pos = 0;
                 }
             }
         }

         if (bytestream2_get_bytes_left(gb) <= 0)
             break;

         delta = bytestream2_get_le16(gb);
         if (delta == 0)
             return 0;
         match_length = 4 + (token & 0x0F);
         if (match_length == 4 + 0x0F) {
             uint8_t current;

             do {
                 current = bytestream2_get_byte(gb);
                 match_length += current;
             } while (current == 255);
         }
         reference_pos = (pos >= delta) ? (pos - delta) : (HISTORY_SIZE + pos - delta);
         if (pos + match_length < HISTORY_SIZE && reference_pos + match_length < HISTORY_SIZE) {
             if (pos >= reference_pos + match_length || reference_pos >= pos + match_length) {
                 memcpy(history + pos, history + reference_pos, match_length);
                 pos += match_length;
             } else {
                 while (match_length-- > 0)
                     history[pos++] = history[reference_pos++];
             }
         } else {
             while (match_length-- > 0) {
                 history[pos++] = history[reference_pos++];
                 if (pos == HISTORY_SIZE) {
                     bytestream2_put_buffer(pb, history, HISTORY_SIZE);
                     pos = 0;
                 }
                 reference_pos %= HISTORY_SIZE;
             }
         }
     }

     bytestream2_put_buffer(pb, history, pos);

     return bytestream2_tell_p(pb);
 }

 static int decode_blocks(AVCodecContext *avctx, AVFrame *p, ThreadFrame *frame,
                          unsigned uncompressed_size)
 {
     NotchLCContext *s = avctx->priv_data;
     GetByteContext rgb, dgb, *gb = &s->gb;
     GetBitContext bit;
     int ylinesize, ulinesize, vlinesize, alinesize;
     uint16_t *dsty, *dstu, *dstv, *dsta;
     int ret;

     s->texture_size_x = bytestream2_get_le32(gb);
     s->texture_size_y = bytestream2_get_le32(gb);

     ret = ff_set_dimensions(avctx, s->texture_size_x, s->texture_size_y);
     if (ret < 0)
         return ret;

     s->uv_offset_data_offset = bytestream2_get_le32(gb);
     if (s->uv_offset_data_offset >= UINT_MAX / 4)
         return AVERROR_INVALIDDATA;
     s->uv_offset_data_offset *= 4;
     if (s->uv_offset_data_offset >= uncompressed_size)
         return AVERROR_INVALIDDATA;

     s->y_control_data_offset = bytestream2_get_le32(gb);
     if (s->y_control_data_offset >= UINT_MAX / 4)
         return AVERROR_INVALIDDATA;
     s->y_control_data_offset *= 4;
     if (s->y_control_data_offset >= uncompressed_size)
         return AVERROR_INVALIDDATA;

     s->a_control_word_offset = bytestream2_get_le32(gb);
     if (s->a_control_word_offset >= UINT_MAX / 4)
         return AVERROR_INVALIDDATA;
     s->a_control_word_offset *= 4;
     if (s->a_control_word_offset >= uncompressed_size)
         return AVERROR_INVALIDDATA;

     s->uv_data_offset = bytestream2_get_le32(gb);
     if (s->uv_data_offset >= UINT_MAX / 4)
         return AVERROR_INVALIDDATA;
     s->uv_data_offset *= 4;
     if (s->uv_data_offset >= uncompressed_size)
         return AVERROR_INVALIDDATA;

     s->y_data_size = bytestream2_get_le32(gb);
     if (s->y_data_size >= UINT_MAX / 4)
         return AVERROR_INVALIDDATA;

     s->a_data_offset = bytestream2_get_le32(gb);
     if (s->a_data_offset >= UINT_MAX / 4)
         return AVERROR_INVALIDDATA;
     s->a_data_offset *= 4;
     if (s->a_data_offset >= uncompressed_size)
         return AVERROR_INVALIDDATA;

     s->a_count_size = bytestream2_get_le32(gb);
     if (s->a_count_size >= UINT_MAX / 4)
         return AVERROR_INVALIDDATA;
     s->a_count_size *= 4;
     if (s->a_count_size >= uncompressed_size)
         return AVERROR_INVALIDDATA;

     s->data_end = bytestream2_get_le32(gb);
     if (s->data_end > uncompressed_size)
         return AVERROR_INVALIDDATA;

     s->y_data_row_offsets = bytestream2_tell(gb);
     if (s->data_end <= s->y_data_size)
         return AVERROR_INVALIDDATA;
     s->y_data_offset = s->data_end - s->y_data_size;
     if (s->y_data_offset <= s->a_data_offset)
         return AVERROR_INVALIDDATA;
     s->uv_count_offset = s->y_data_offset - s->a_data_offset;

     if ((ret = ff_thread_get_buffer(avctx, frame, 0)) < 0)
         return ret;

     rgb = *gb;
     dgb = *gb;
     bytestream2_seek(&rgb, s->y_data_row_offsets, SEEK_SET);
     bytestream2_seek(gb, s->y_control_data_offset, SEEK_SET);

     if (bytestream2_get_bytes_left(gb) < (avctx->height + 3) / 4 * ((avctx->width + 3) / 4) * 4)
         return AVERROR_INVALIDDATA;

     dsty = (uint16_t *)p->data[0];
     dsta = (uint16_t *)p->data[3];
     ylinesize = p->linesize[0] / 2;
     alinesize = p->linesize[3] / 2;

     for (int y = 0; y < avctx->height; y += 4) {
         const unsigned row_offset = bytestream2_get_le32(&rgb);

         bytestream2_seek(&dgb, s->y_data_offset + row_offset, SEEK_SET);

         init_get_bits8(&bit, dgb.buffer, bytestream2_get_bytes_left(&dgb));
         for (int x = 0; x < avctx->width; x += 4) {
             unsigned item = bytestream2_get_le32(gb);
             unsigned y_min = item & 4095;
             unsigned y_max = (item >> 12) & 4095;
             unsigned y_diff = y_max - y_min;
             unsigned control[4];

             control[0] = (item >> 24) & 3;
             control[1] = (item >> 26) & 3;
             control[2] = (item >> 28) & 3;
             control[3] = (item >> 30) & 3;

             for (int i = 0; i < 4; i++) {
                 const int nb_bits = control[i] + 1;
                 const int div = (1 << nb_bits) - 1;
                 const int add = div - 1;

                 dsty[x + i * ylinesize + 0] = av_clip_uintp2(y_min + ((y_diff * get_bits(&bit, nb_bits) + add) / div), 12);
                 dsty[x + i * ylinesize + 1] = av_clip_uintp2(y_min + ((y_diff * get_bits(&bit, nb_bits) + add) / div), 12);
                 dsty[x + i * ylinesize + 2] = av_clip_uintp2(y_min + ((y_diff * get_bits(&bit, nb_bits) + add) / div), 12);
                 dsty[x + i * ylinesize + 3] = av_clip_uintp2(y_min + ((y_diff * get_bits(&bit, nb_bits) + add) / div), 12);
             }
         }

         dsty += 4 * ylinesize;
     }

     rgb = *gb;
     dgb = *gb;
     bytestream2_seek(gb, s->a_control_word_offset, SEEK_SET);
     if (s->uv_count_offset == s->a_control_word_offset) {
         for (int y = 0; y < avctx->height; y++) {
             for (int x = 0; x < avctx->width; x++)
                 dsta[x] = 4095;
             dsta += alinesize;
         }
     } else {
         if (bytestream2_get_bytes_left(gb) < (avctx->height + 15) / 16 * ((avctx->width + 15) / 16) * 8)
             return AVERROR_INVALIDDATA;

         for (int y = 0; y < avctx->height; y += 16) {
             for (int x = 0; x < avctx->width; x += 16) {
                 unsigned m = bytestream2_get_le32(gb);
                 unsigned offset = bytestream2_get_le32(gb);
                 unsigned alpha0, alpha1;
                 uint64_t control;

                 if (offset >= UINT_MAX / 4)
                     return AVERROR_INVALIDDATA;
                 offset = offset * 4 + s->uv_data_offset + s->a_data_offset;
                 if (offset >= s->data_end)
                     return AVERROR_INVALIDDATA;

                 bytestream2_seek(&dgb, offset, SEEK_SET);
                 control = bytestream2_get_le64(&dgb);
                 alpha0 = control & 0xFF;
                 alpha1 = (control >> 8) & 0xFF;
                 control = control >> 16;

                 for (int by = 0; by < 4; by++) {
                     for (int bx = 0; bx < 4; bx++) {
                         switch (m & 3) {
                         case 0:
                             for (int i = 0; i < 4; i++) {
                                 for (int j = 0; j < 4; j++) {
                                     dsta[x + (i + by * 4) * alinesize + bx * 4 + j] = 0;
                                 }
                             }
                             break;
                         case 1:
                             for (int i = 0; i < 4; i++) {
                                 for (int j = 0; j < 4; j++) {
                                     dsta[x + (i + by * 4) * alinesize + bx * 4 + j] = 4095;
                                 }
                             }
                             break;
                         case 2:
                             for (int i = 0; i < 4; i++) {
                                 for (int j = 0; j < 4; j++) {
                                     dsta[x + (i + by * 4) * alinesize + bx * 4 + j] = (alpha0 + (alpha1 - alpha0) * (control & 7)) << 4;
                                 }
                             }
                             break;
                         default:
                             return AVERROR_INVALIDDATA;
                         }

                         control >>= 3;
                         m >>= 2;
                     }
                 }
             }

             dsta += 16 * alinesize;
         }
     }

     bytestream2_seek(&rgb, s->uv_offset_data_offset, SEEK_SET);

     dstu = (uint16_t *)p->data[1];
     dstv = (uint16_t *)p->data[2];
     ulinesize = p->linesize[1] / 2;
     vlinesize = p->linesize[2] / 2;

     for (int y = 0; y < avctx->height; y += 16) {
         for (int x = 0; x < avctx->width; x += 16) {
             unsigned offset = bytestream2_get_le32(&rgb) * 4;
             int u[16][16] = { 0 }, v[16][16] = { 0 };
             int u0, v0, u1, v1, udif, vdif;
             unsigned escape, is8x8, loc;

             bytestream2_seek(&dgb, s->uv_data_offset + offset, SEEK_SET);

             is8x8 = bytestream2_get_le16(&dgb);
             escape = bytestream2_get_le16(&dgb);

             if (escape == 0 && is8x8 == 0) {
                 u0 = bytestream2_get_byte(&dgb);
                 v0 = bytestream2_get_byte(&dgb);
                 u1 = bytestream2_get_byte(&dgb);
                 v1 = bytestream2_get_byte(&dgb);
                 loc = bytestream2_get_le32(&dgb);
                 u0 = (u0 << 4) | (u0 & 0xF);
                 v0 = (v0 << 4) | (v0 & 0xF);
                 u1 = (u1 << 4) | (u1 & 0xF);
                 v1 = (v1 << 4) | (v1 & 0xF);
                 udif = u1 - u0;
                 vdif = v1 - v0;

                 for (int i = 0; i < 16; i += 4) {
                     for (int j = 0; j < 16; j += 4) {
                         for (int ii = 0; ii < 4; ii++) {
                             for (int jj = 0; jj < 4; jj++) {
                                 u[i + ii][j + jj] = u0 + ((udif * (int)(loc & 3) + 2) / 3);
                                 v[i + ii][j + jj] = v0 + ((vdif * (int)(loc & 3) + 2) / 3);
                             }
                         }

                         loc >>= 2;
                     }
                 }
             } else {
                 for (int i = 0; i < 16; i += 8) {
                     for (int j = 0; j < 16; j += 8) {
                         if (is8x8 & 1) {
                             u0 = bytestream2_get_byte(&dgb);
                             v0 = bytestream2_get_byte(&dgb);
                             u1 = bytestream2_get_byte(&dgb);
                             v1 = bytestream2_get_byte(&dgb);
                             loc = bytestream2_get_le32(&dgb);
                             u0 = (u0 << 4) | (u0 & 0xF);
                             v0 = (v0 << 4) | (v0 & 0xF);
                             u1 = (u1 << 4) | (u1 & 0xF);
                             v1 = (v1 << 4) | (v1 & 0xF);
                             udif = u1 - u0;
                             vdif = v1 - v0;

                             for (int ii = 0; ii < 8; ii += 2) {
                                 for (int jj = 0; jj < 8; jj += 2) {
                                     for (int iii = 0; iii < 2; iii++) {
                                         for (int jjj = 0; jjj < 2; jjj++) {
                                             u[i + ii + iii][j + jj + jjj] = u0 + ((udif * (int)(loc & 3) + 2) / 3);
                                             v[i + ii + iii][j + jj + jjj] = v0 + ((vdif * (int)(loc & 3) + 2) / 3);
                                         }
                                     }

                                     loc >>= 2;
                                 }
                             }
                         } else if (escape) {
                             for (int ii = 0; ii < 8; ii += 4) {
                                 for (int jj = 0; jj < 8; jj += 4) {
                                     u0 = bytestream2_get_byte(&dgb);
                                     v0 = bytestream2_get_byte(&dgb);
                                     u1 = bytestream2_get_byte(&dgb);
                                     v1 = bytestream2_get_byte(&dgb);
                                     loc = bytestream2_get_le32(&dgb);
                                     u0 = (u0 << 4) | (u0 & 0xF);
                                     v0 = (v0 << 4) | (v0 & 0xF);
                                     u1 = (u1 << 4) | (u1 & 0xF);
                                     v1 = (v1 << 4) | (v1 & 0xF);
                                     udif = u1 - u0;
                                     vdif = v1 - v0;

                                     for (int iii = 0; iii < 4; iii++) {
                                         for (int jjj = 0; jjj < 4; jjj++) {
                                             u[i + ii + iii][j + jj + jjj] = u0 + ((udif * (int)(loc & 3) + 2) / 3);
                                             v[i + ii + iii][j + jj + jjj] = v0 + ((vdif * (int)(loc & 3) + 2) / 3);

                                             loc >>= 2;
                                         }
                                     }
                                 }
                             }
                         }

                         is8x8 >>= 1;
                     }
                 }
             }

             for (int i = 0; i < 16; i++) {
                 for (int j = 0; j < 16; j++) {
                     dstu[x + i * ulinesize + j] = u[i][j];
                     dstv[x + i * vlinesize + j] = v[i][j];
                 }
             }
         }

         dstu += 16 * ulinesize;
         dstv += 16 * vlinesize;
     }

     return 0;
 }

 static int decode_frame(AVCodecContext *avctx,
                         void *data, int *got_frame,
                         AVPacket *avpkt)
 {
     NotchLCContext *s = avctx->priv_data;
     ThreadFrame frame = { .f = data };
     GetByteContext *gb = &s->gb;
     PutByteContext *pb = &s->pb;
     unsigned uncompressed_size;
     AVFrame *p = data;
     int ret;

     if (avpkt->size <= 40)
         return AVERROR_INVALIDDATA;

     bytestream2_init(gb, avpkt->data, avpkt->size);

     if (bytestream2_get_le32(gb) != MKBETAG('N','L','C','1'))
         return AVERROR_INVALIDDATA;

     uncompressed_size = bytestream2_get_le32(gb);
     s->compressed_size = bytestream2_get_le32(gb);
     s->format = bytestream2_get_le32(gb);

     if (s->format > 2)
         return AVERROR_PATCHWELCOME;

     if (s->format == 0) {
         ret = ff_lzf_uncompress(gb, &s->lzf_buffer, &s->lzf_size);
         if (ret < 0)
             return ret;

         if (uncompressed_size > s->lzf_size)
             return AVERROR_INVALIDDATA;

         bytestream2_init(gb, s->lzf_buffer, uncompressed_size);
     } else if (s->format == 1) {
         av_fast_padded_malloc(&s->uncompressed_buffer, &s->uncompressed_size,
                               uncompressed_size);
         if (!s->uncompressed_buffer)
             return AVERROR(ENOMEM);

         bytestream2_init_writer(pb, s->uncompressed_buffer, s->uncompressed_size);

         ret = lz4_decompress(avctx, gb, pb);
         if (ret != uncompressed_size)
             return AVERROR_INVALIDDATA;

         bytestream2_init(gb, s->uncompressed_buffer, uncompressed_size);
     }

     ret = decode_blocks(avctx, p, &frame, uncompressed_size);
     if (ret < 0)
         return ret;

     p->pict_type = AV_PICTURE_TYPE_I;
     p->key_frame = 1;

     *got_frame = 1;

     return avpkt->size;
 }

 static av_cold int decode_end(AVCodecContext *avctx)
 {
     NotchLCContext *s = avctx->priv_data;

     av_freep(&s->uncompressed_buffer);
     s->uncompressed_size = 0;
     av_freep(&s->lzf_buffer);
     s->lzf_size = 0;

     return 0;
 }

 AVCodec ff_notchlc_decoder = {
     .name             = "notchlc",
     .long_name        = NULL_IF_CONFIG_SMALL("NotchLC"),
     .type             = AVMEDIA_TYPE_VIDEO,
     .id               = AV_CODEC_ID_NOTCHLC,
     .priv_data_size   = sizeof(NotchLCContext),
     .init             = decode_init,
     .close            = decode_end,
     .decode           = decode_frame,
     .capabilities     = AV_CODEC_CAP_DR1 | AV_CODEC_CAP_FRAME_THREADS,
 };
	/*
	* NotchLC decoder
	* Copyright (c) 2020 Paul B Mahol
	*
	* 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 <stdio.h>
	#include <stdlib.h>
	#include <string.h>

	#define BITSTREAM_READER_LE
	#include "libavutil/intreadwrite.h"
	#include "avcodec.h"
	#include "bytestream.h"
	#include "get_bits.h"
	#include "internal.h"
	#include "lzf.h"
	#include "thread.h"

	typedef struct NotchLCContext {
	unsigned compressed_size;
	unsigned format;

	uint8_t *uncompressed_buffer;
	unsigned uncompressed_size;

	uint8_t *lzf_buffer;
	int64_t lzf_size;

	unsigned texture_size_x;
	unsigned texture_size_y;
	unsigned y_data_row_offsets;
	unsigned uv_offset_data_offset;
	unsigned y_control_data_offset;
	unsigned a_control_word_offset;
	unsigned y_data_offset;
	unsigned uv_data_offset;
	unsigned y_data_size;
	unsigned a_data_offset;
	unsigned uv_count_offset;
	unsigned a_count_size;
	unsigned data_end;

	GetByteContext gb;
	PutByteContext pb;
	} NotchLCContext;

	static av_cold int decode_init(AVCodecContext *avctx)
	{
	avctx->pix_fmt = AV_PIX_FMT_YUVA444P12;
	avctx->color_range = AVCOL_RANGE_JPEG;
	avctx->colorspace = AVCOL_SPC_RGB;
	avctx->color_primaries = AVCOL_PRI_BT709;
	avctx->color_trc = AVCOL_TRC_IEC61966_2_1;

	return 0;
	}

	#define HISTORY_SIZE (64 * 1024)

	static int lz4_decompress(AVCodecContext *avctx,
	GetByteContext *gb,
	PutByteContext *pb)
	{
	unsigned reference_pos, match_length, delta, pos = 0;
	uint8_t history[64 * 1024];

	while (bytestream2_get_bytes_left(gb) > 0) {
	uint8_t token = bytestream2_get_byte(gb);
	unsigned num_literals = token >> 4;

	if (num_literals == 15) {
	unsigned char current;
	do {
	current = bytestream2_get_byte(gb);
	num_literals += current;
	} while (current == 255);
	}

	if (pos + num_literals < HISTORY_SIZE) {
	bytestream2_get_buffer(gb, history + pos, num_literals);
	pos += num_literals;
	} else {
	while (num_literals-- > 0) {
	history[pos++] = bytestream2_get_byte(gb);
	if (pos == HISTORY_SIZE) {
	bytestream2_put_buffer(pb, history, HISTORY_SIZE);
	pos = 0;
	}
	}
	}

	if (bytestream2_get_bytes_left(gb) <= 0)
	break;

	delta = bytestream2_get_le16(gb);
	if (delta == 0)
	return 0;
	match_length = 4 + (token & 0x0F);
	if (match_length == 4 + 0x0F) {
	uint8_t current;

	do {
	current = bytestream2_get_byte(gb);
	match_length += current;
	} while (current == 255);
	}
	reference_pos = (pos >= delta) ? (pos - delta) : (HISTORY_SIZE + pos - delta);
	if (pos + match_length < HISTORY_SIZE && reference_pos + match_length < HISTORY_SIZE) {
	if (pos >= reference_pos + match_length \|\| reference_pos >= pos + match_length) {
	memcpy(history + pos, history + reference_pos, match_length);
	pos += match_length;
	} else {
	while (match_length-- > 0)
	history[pos++] = history[reference_pos++];
	}
	} else {
	while (match_length-- > 0) {
	history[pos++] = history[reference_pos++];
	if (pos == HISTORY_SIZE) {
	bytestream2_put_buffer(pb, history, HISTORY_SIZE);
	pos = 0;
	}
	reference_pos %= HISTORY_SIZE;
	}
	}
	}

	bytestream2_put_buffer(pb, history, pos);

	return bytestream2_tell_p(pb);
	}

	static int decode_blocks(AVCodecContext avctx, AVFrame p, ThreadFrame *frame,
	unsigned uncompressed_size)
	{
	NotchLCContext *s = avctx->priv_data;
	GetByteContext rgb, dgb, *gb = &s->gb;
	GetBitContext bit;
	int ylinesize, ulinesize, vlinesize, alinesize;
	uint16_t dsty, dstu, dstv, dsta;
	int ret;

	s->texture_size_x = bytestream2_get_le32(gb);
	s->texture_size_y = bytestream2_get_le32(gb);

	ret = ff_set_dimensions(avctx, s->texture_size_x, s->texture_size_y);
	if (ret < 0)
	return ret;

	s->uv_offset_data_offset = bytestream2_get_le32(gb);
	if (s->uv_offset_data_offset >= UINT_MAX / 4)
	return AVERROR_INVALIDDATA;
	s->uv_offset_data_offset *= 4;
	if (s->uv_offset_data_offset >= uncompressed_size)
	return AVERROR_INVALIDDATA;

	s->y_control_data_offset = bytestream2_get_le32(gb);
	if (s->y_control_data_offset >= UINT_MAX / 4)
	return AVERROR_INVALIDDATA;
	s->y_control_data_offset *= 4;
	if (s->y_control_data_offset >= uncompressed_size)
	return AVERROR_INVALIDDATA;

	s->a_control_word_offset = bytestream2_get_le32(gb);
	if (s->a_control_word_offset >= UINT_MAX / 4)
	return AVERROR_INVALIDDATA;
	s->a_control_word_offset *= 4;
	if (s->a_control_word_offset >= uncompressed_size)
	return AVERROR_INVALIDDATA;

	s->uv_data_offset = bytestream2_get_le32(gb);
	if (s->uv_data_offset >= UINT_MAX / 4)
	return AVERROR_INVALIDDATA;
	s->uv_data_offset *= 4;
	if (s->uv_data_offset >= uncompressed_size)
	return AVERROR_INVALIDDATA;

	s->y_data_size = bytestream2_get_le32(gb);
	if (s->y_data_size >= UINT_MAX / 4)
	return AVERROR_INVALIDDATA;

	s->a_data_offset = bytestream2_get_le32(gb);
	if (s->a_data_offset >= UINT_MAX / 4)
	return AVERROR_INVALIDDATA;
	s->a_data_offset *= 4;
	if (s->a_data_offset >= uncompressed_size)
	return AVERROR_INVALIDDATA;

	s->a_count_size = bytestream2_get_le32(gb);
	if (s->a_count_size >= UINT_MAX / 4)
	return AVERROR_INVALIDDATA;
	s->a_count_size *= 4;
	if (s->a_count_size >= uncompressed_size)
	return AVERROR_INVALIDDATA;

	s->data_end = bytestream2_get_le32(gb);
	if (s->data_end > uncompressed_size)
	return AVERROR_INVALIDDATA;

	s->y_data_row_offsets = bytestream2_tell(gb);
	if (s->data_end <= s->y_data_size)
	return AVERROR_INVALIDDATA;
	s->y_data_offset = s->data_end - s->y_data_size;
	if (s->y_data_offset <= s->a_data_offset)
	return AVERROR_INVALIDDATA;
	s->uv_count_offset = s->y_data_offset - s->a_data_offset;

	if ((ret = ff_thread_get_buffer(avctx, frame, 0)) < 0)
	return ret;

	rgb = *gb;
	dgb = *gb;
	bytestream2_seek(&rgb, s->y_data_row_offsets, SEEK_SET);
	bytestream2_seek(gb, s->y_control_data_offset, SEEK_SET);

	if (bytestream2_get_bytes_left(gb) < (avctx->height + 3) / 4 * ((avctx->width + 3) / 4) * 4)
	return AVERROR_INVALIDDATA;

	dsty = (uint16_t *)p->data[0];
	dsta = (uint16_t *)p->data[3];
	ylinesize = p->linesize[0] / 2;
	alinesize = p->linesize[3] / 2;

	for (int y = 0; y < avctx->height; y += 4) {
	const unsigned row_offset = bytestream2_get_le32(&rgb);

	bytestream2_seek(&dgb, s->y_data_offset + row_offset, SEEK_SET);

	init_get_bits8(&bit, dgb.buffer, bytestream2_get_bytes_left(&dgb));
	for (int x = 0; x < avctx->width; x += 4) {
	unsigned item = bytestream2_get_le32(gb);
	unsigned y_min = item & 4095;
	unsigned y_max = (item >> 12) & 4095;
	unsigned y_diff = y_max - y_min;
	unsigned control[4];

	control[0] = (item >> 24) & 3;
	control[1] = (item >> 26) & 3;
	control[2] = (item >> 28) & 3;
	control[3] = (item >> 30) & 3;

	for (int i = 0; i < 4; i++) {
	const int nb_bits = control[i] + 1;
	const int div = (1 << nb_bits) - 1;
	const int add = div - 1;

	dsty[x + i * ylinesize + 0] = av_clip_uintp2(y_min + ((y_diff * get_bits(&bit, nb_bits) + add) / div), 12);
	dsty[x + i * ylinesize + 1] = av_clip_uintp2(y_min + ((y_diff * get_bits(&bit, nb_bits) + add) / div), 12);
	dsty[x + i * ylinesize + 2] = av_clip_uintp2(y_min + ((y_diff * get_bits(&bit, nb_bits) + add) / div), 12);
	dsty[x + i * ylinesize + 3] = av_clip_uintp2(y_min + ((y_diff * get_bits(&bit, nb_bits) + add) / div), 12);
	}
	}

	dsty += 4 * ylinesize;
	}

	rgb = *gb;
	dgb = *gb;
	bytestream2_seek(gb, s->a_control_word_offset, SEEK_SET);
	if (s->uv_count_offset == s->a_control_word_offset) {
	for (int y = 0; y < avctx->height; y++) {
	for (int x = 0; x < avctx->width; x++)
	dsta[x] = 4095;
	dsta += alinesize;
	}
	} else {
	if (bytestream2_get_bytes_left(gb) < (avctx->height + 15) / 16 * ((avctx->width + 15) / 16) * 8)
	return AVERROR_INVALIDDATA;

	for (int y = 0; y < avctx->height; y += 16) {
	for (int x = 0; x < avctx->width; x += 16) {
	unsigned m = bytestream2_get_le32(gb);
	unsigned offset = bytestream2_get_le32(gb);
	unsigned alpha0, alpha1;
	uint64_t control;

	if (offset >= UINT_MAX / 4)
	return AVERROR_INVALIDDATA;
	offset = offset * 4 + s->uv_data_offset + s->a_data_offset;
	if (offset >= s->data_end)
	return AVERROR_INVALIDDATA;

	bytestream2_seek(&dgb, offset, SEEK_SET);
	control = bytestream2_get_le64(&dgb);
	alpha0 = control & 0xFF;
	alpha1 = (control >> 8) & 0xFF;
	control = control >> 16;

	for (int by = 0; by < 4; by++) {
	for (int bx = 0; bx < 4; bx++) {
	switch (m & 3) {
	case 0:
	for (int i = 0; i < 4; i++) {
	for (int j = 0; j < 4; j++) {
	dsta[x + (i + by * 4) * alinesize + bx * 4 + j] = 0;
	}
	}
	break;
	case 1:
	for (int i = 0; i < 4; i++) {
	for (int j = 0; j < 4; j++) {
	dsta[x + (i + by * 4) * alinesize + bx * 4 + j] = 4095;
	}
	}
	break;
	case 2:
	for (int i = 0; i < 4; i++) {
	for (int j = 0; j < 4; j++) {
	dsta[x + (i + by * 4) * alinesize + bx * 4 + j] = (alpha0 + (alpha1 - alpha0) * (control & 7)) << 4;
	}
	}
	break;
	default:
	return AVERROR_INVALIDDATA;
	}

	control >>= 3;
	m >>= 2;
	}
	}
	}

	dsta += 16 * alinesize;
	}
	}

	bytestream2_seek(&rgb, s->uv_offset_data_offset, SEEK_SET);

	dstu = (uint16_t *)p->data[1];
	dstv = (uint16_t *)p->data[2];
	ulinesize = p->linesize[1] / 2;
	vlinesize = p->linesize[2] / 2;

	for (int y = 0; y < avctx->height; y += 16) {
	for (int x = 0; x < avctx->width; x += 16) {
	unsigned offset = bytestream2_get_le32(&rgb) * 4;
	int u[16][16] = { 0 }, v[16][16] = { 0 };
	int u0, v0, u1, v1, udif, vdif;
	unsigned escape, is8x8, loc;

	bytestream2_seek(&dgb, s->uv_data_offset + offset, SEEK_SET);

	is8x8 = bytestream2_get_le16(&dgb);
	escape = bytestream2_get_le16(&dgb);

	if (escape == 0 && is8x8 == 0) {
	u0 = bytestream2_get_byte(&dgb);
	v0 = bytestream2_get_byte(&dgb);
	u1 = bytestream2_get_byte(&dgb);
	v1 = bytestream2_get_byte(&dgb);
	loc = bytestream2_get_le32(&dgb);
	u0 = (u0 << 4) \| (u0 & 0xF);
	v0 = (v0 << 4) \| (v0 & 0xF);
	u1 = (u1 << 4) \| (u1 & 0xF);
	v1 = (v1 << 4) \| (v1 & 0xF);
	udif = u1 - u0;
	vdif = v1 - v0;

	for (int i = 0; i < 16; i += 4) {
	for (int j = 0; j < 16; j += 4) {
	for (int ii = 0; ii < 4; ii++) {
	for (int jj = 0; jj < 4; jj++) {
	u[i + ii][j + jj] = u0 + ((udif * (int)(loc & 3) + 2) / 3);
	v[i + ii][j + jj] = v0 + ((vdif * (int)(loc & 3) + 2) / 3);
	}
	}

	loc >>= 2;
	}
	}
	} else {
	for (int i = 0; i < 16; i += 8) {
	for (int j = 0; j < 16; j += 8) {
	if (is8x8 & 1) {
	u0 = bytestream2_get_byte(&dgb);
	v0 = bytestream2_get_byte(&dgb);
	u1 = bytestream2_get_byte(&dgb);
	v1 = bytestream2_get_byte(&dgb);
	loc = bytestream2_get_le32(&dgb);
	u0 = (u0 << 4) \| (u0 & 0xF);
	v0 = (v0 << 4) \| (v0 & 0xF);
	u1 = (u1 << 4) \| (u1 & 0xF);
	v1 = (v1 << 4) \| (v1 & 0xF);
	udif = u1 - u0;
	vdif = v1 - v0;

	for (int ii = 0; ii < 8; ii += 2) {
	for (int jj = 0; jj < 8; jj += 2) {
	for (int iii = 0; iii < 2; iii++) {
	for (int jjj = 0; jjj < 2; jjj++) {
	u[i + ii + iii][j + jj + jjj] = u0 + ((udif * (int)(loc & 3) + 2) / 3);
	v[i + ii + iii][j + jj + jjj] = v0 + ((vdif * (int)(loc & 3) + 2) / 3);
	}
	}

	loc >>= 2;
	}
	}
	} else if (escape) {
	for (int ii = 0; ii < 8; ii += 4) {
	for (int jj = 0; jj < 8; jj += 4) {
	u0 = bytestream2_get_byte(&dgb);
	v0 = bytestream2_get_byte(&dgb);
	u1 = bytestream2_get_byte(&dgb);
	v1 = bytestream2_get_byte(&dgb);
	loc = bytestream2_get_le32(&dgb);
	u0 = (u0 << 4) \| (u0 & 0xF);
	v0 = (v0 << 4) \| (v0 & 0xF);
	u1 = (u1 << 4) \| (u1 & 0xF);
	v1 = (v1 << 4) \| (v1 & 0xF);
	udif = u1 - u0;
	vdif = v1 - v0;

	for (int iii = 0; iii < 4; iii++) {
	for (int jjj = 0; jjj < 4; jjj++) {
	u[i + ii + iii][j + jj + jjj] = u0 + ((udif * (int)(loc & 3) + 2) / 3);
	v[i + ii + iii][j + jj + jjj] = v0 + ((vdif * (int)(loc & 3) + 2) / 3);

	loc >>= 2;
	}
	}
	}
	}
	}

	is8x8 >>= 1;
	}
	}
	}

	for (int i = 0; i < 16; i++) {
	for (int j = 0; j < 16; j++) {
	dstu[x + i * ulinesize + j] = u[i][j];
	dstv[x + i * vlinesize + j] = v[i][j];
	}
	}
	}

	dstu += 16 * ulinesize;
	dstv += 16 * vlinesize;
	}

	return 0;
	}

	static int decode_frame(AVCodecContext *avctx,
	void data, int got_frame,
	AVPacket *avpkt)
	{
	NotchLCContext *s = avctx->priv_data;
	ThreadFrame frame = { .f = data };
	GetByteContext *gb = &s->gb;
	PutByteContext *pb = &s->pb;
	unsigned uncompressed_size;
	AVFrame *p = data;
	int ret;

	if (avpkt->size <= 40)
	return AVERROR_INVALIDDATA;

	bytestream2_init(gb, avpkt->data, avpkt->size);

	if (bytestream2_get_le32(gb) != MKBETAG('N','L','C','1'))
	return AVERROR_INVALIDDATA;

	uncompressed_size = bytestream2_get_le32(gb);
	s->compressed_size = bytestream2_get_le32(gb);
	s->format = bytestream2_get_le32(gb);

	if (s->format > 2)
	return AVERROR_PATCHWELCOME;

	if (s->format == 0) {
	ret = ff_lzf_uncompress(gb, &s->lzf_buffer, &s->lzf_size);
	if (ret < 0)
	return ret;

	if (uncompressed_size > s->lzf_size)
	return AVERROR_INVALIDDATA;

	bytestream2_init(gb, s->lzf_buffer, uncompressed_size);
	} else if (s->format == 1) {
	av_fast_padded_malloc(&s->uncompressed_buffer, &s->uncompressed_size,
	uncompressed_size);
	if (!s->uncompressed_buffer)
	return AVERROR(ENOMEM);

	bytestream2_init_writer(pb, s->uncompressed_buffer, s->uncompressed_size);

	ret = lz4_decompress(avctx, gb, pb);
	if (ret != uncompressed_size)
	return AVERROR_INVALIDDATA;

	bytestream2_init(gb, s->uncompressed_buffer, uncompressed_size);
	}

	ret = decode_blocks(avctx, p, &frame, uncompressed_size);
	if (ret < 0)
	return ret;

	p->pict_type = AV_PICTURE_TYPE_I;
	p->key_frame = 1;

	*got_frame = 1;

	return avpkt->size;
	}

	static av_cold int decode_end(AVCodecContext *avctx)
	{
	NotchLCContext *s = avctx->priv_data;

	av_freep(&s->uncompressed_buffer);
	s->uncompressed_size = 0;
	av_freep(&s->lzf_buffer);
	s->lzf_size = 0;

	return 0;
	}

	AVCodec ff_notchlc_decoder = {
	.name = "notchlc",
	.long_name = NULL_IF_CONFIG_SMALL("NotchLC"),
	.type = AVMEDIA_TYPE_VIDEO,
	.id = AV_CODEC_ID_NOTCHLC,
	.priv_data_size = sizeof(NotchLCContext),
	.init = decode_init,
	.close = decode_end,
	.decode = decode_frame,
	.capabilities = AV_CODEC_CAP_DR1 \| AV_CODEC_CAP_FRAME_THREADS,
	};