Escape 130 (RPL) decoder

1 files changed, 307 insertions, 0 deletions

diff --git a/libavcodec/escape130.c b/libavcodec/escape130.c
new file mode 100644
index 0000000000..cd977cf83b
--- /dev/null
+++ b/libavcodec/escape130.c
@@ -0,0 +1,307 @@
+/*
+ * 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 ALT_BITSTREAM_READER_LE
+#include "bitstream.h"
+
+typedef struct Escape130Context {
+    AVFrame frame;
+} Escape130Context;
+
+static int can_safely_read(GetBitContext* gb, int bits) {
+    return get_bits_count(gb) + bits <= gb->size_in_bits;
+}
+
+/**
+ * Initialize the decoder
+ * @param avctx decoder context
+ * @return 0 success, negative on error
+ */
+static av_cold int escape130_decode_init(AVCodecContext *avctx)
+{
+    avctx->pix_fmt = PIX_FMT_YUV420P;
+
+    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);
+
+    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 (!can_safely_read(gb, 1))
+        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,
+                                  const uint8_t *buf, int buf_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;
+
+    AVFrame new_frame = { { 0 } };
+
+    init_get_bits(&gb, buf, buf_size * 8);
+
+    if (!can_safely_read(&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(NULL, 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;
+                cb = old_cb[0] / 8;
+                cr = old_cr[0] / 8;
+            } else {
+                y[0] = y[1] = y[2] = y[3] = 0;
+                cb = cr = 16;
+            }
+        } else {
+            if (get_bits1(&gb)) {
+                unsigned sign_selector = get_bits(&gb, 6);
+                unsigned difference_selector = get_bits(&gb, 2);
+                unsigned y_base = 2 * get_bits(&gb, 5);
+                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} };
+                for (i = 0; i < 4; i++) {
+                    y[i] = av_clip(y_base + offset_table[difference_selector] *
+                                            sign_table[sign_selector][i], 0, 63);
+                }
+            } else if (get_bits1(&gb)) {
+                if (get_bits1(&gb)) {
+                    unsigned y_base = get_bits(&gb, 6);
+                    for (i = 0; i < 4; i++)
+                        y[i] = y_base;
+                } else {
+                    unsigned adjust_index = get_bits(&gb, 3);
+                    static const int8_t adjust[] = {-4, -3, -2, -1, 1, 2, 3, 4};
+                    for (i = 0; i < 4; i++)
+                        y[i] = av_clip(y[i] + adjust[adjust_index], 0, 63);
+                }
+            }
+
+            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,  0, -1, -2, -1, -1 } };
+                    cb = (cb + adjust[0][adjust_index]) & 31;
+                    cr = (cr + adjust[1][adjust_index]) & 31;
+                }
+            }
+        }
+
+        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(NULL, 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 escape130_decoder = {
+    "escape130",
+    CODEC_TYPE_VIDEO,
+    CODEC_ID_ESCAPE130,
+    sizeof(Escape130Context),
+    escape130_decode_init,
+    NULL,
+    escape130_decode_close,
+    escape130_decode_frame,
+    CODEC_CAP_DR1,
+};