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-rw-r--r--kopete/protocols/msn/webcam/libmimic/decode.c311
1 files changed, 311 insertions, 0 deletions
diff --git a/kopete/protocols/msn/webcam/libmimic/decode.c b/kopete/protocols/msn/webcam/libmimic/decode.c
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+++ b/kopete/protocols/msn/webcam/libmimic/decode.c
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+/* Copyright (C) 2005 Ole Andr� Vadla Ravn�s <[email protected]>
+ *
+ * This library 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.
+ *
+ * This library 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 this library; if not, write to the Free Software
+ * Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA
+ */
+
+#include <string.h>
+#include "mimic-private.h"
+
+
+static gboolean decode(MimCtx *ctx, gboolean is_pframe);
+
+/**
+ * Decode a MIMIC-encoded frame into RGB data.
+ *
+ * @param ctx the mimic context
+ * @param input_buffer buffer containing the MIMIC-encoded frame to decode
+ * @param output_buffer buffer that will receive the decoded frame in RGB 24-bpp packed pixel top-down format
+ * (use #mimic_get_property to determine the required buffer size, as well as frame width and height)
+ * @returns #TRUE on success
+ */
+gboolean mimic_decode_frame(MimCtx *ctx,
+ const guchar *input_buffer,
+ guchar *output_buffer)
+{
+ gboolean result, is_pframe;
+ guchar *input_y, *input_cr, *input_cb;
+ gint width, height;
+
+ /*
+ * Some sanity checks.
+ */
+ if (ctx == NULL || input_buffer == NULL || output_buffer == NULL)
+ {
+ return FALSE;
+ }
+
+ if (!ctx->decoder_initialized)
+ {
+ return FALSE;
+ }
+
+ /*
+ * Get frame dimensions.
+ */
+ width = GUINT16_FROM_LE(*((guint16 *) (input_buffer + 4)));
+ height = GUINT16_FROM_LE(*((guint16 *) (input_buffer + 6)));
+
+ /*
+ * Resolution changing is not supported.
+ */
+ if (width != ctx->frame_width ||
+ height != ctx->frame_height)
+ {
+ return FALSE;
+ }
+
+ /*
+ * Increment frame counter.
+ */
+ ctx->frame_num++;
+
+ /*
+ * Initialize state.
+ */
+ ctx->quality = GUINT16_FROM_LE(*((guint16 *) (input_buffer + 2)));
+ is_pframe = GUINT32_FROM_LE(*((guint32 *) (input_buffer + 12)));
+ ctx->num_coeffs = input_buffer[16];
+
+ ctx->data_buffer = (gchar *) (input_buffer + 20);
+ ctx->data_index = 0;
+ ctx->cur_chunk_len = 16;
+ ctx->read_odd = FALSE;
+
+ /*
+ * Decode frame.
+ */
+ if (!(is_pframe && ctx->prev_frame_buf == NULL))
+ result = decode(ctx, is_pframe);
+ else
+ {
+ result = FALSE;
+ }
+
+ /*
+ * Perform YUV 420 to RGB conversion.
+ */
+ input_y = ctx->cur_frame_buf;
+ input_cr = ctx->cur_frame_buf + ctx->y_size;
+ input_cb = ctx->cur_frame_buf + ctx->y_size + ctx->crcb_size;
+
+ _yuv_to_rgb(input_y,
+ input_cb,
+ input_cr,
+ output_buffer,
+ ctx->frame_width,
+ ctx->frame_height);
+
+ return result;
+}
+
+/*
+ * decode_main
+ *
+ * Main decoding loop.
+ */
+static gboolean decode(MimCtx *ctx, gboolean is_pframe)
+{
+ gint y, x, i, j, chrom_ch, *bptr, base_offset, offset;
+ gint dct_block[64];
+ guchar *src, *dst, *p;
+ guint32 bit;
+
+ /*
+ * Clear Cr and Cb planes.
+ */
+ p = ctx->cur_frame_buf + ctx->y_size;
+ memset(p, 128, 2 * ctx->crcb_size);
+
+ /*
+ * Decode Y plane.
+ */
+ for (y = 0; y < ctx->num_vblocks_y; y++) {
+
+ base_offset = ctx->y_stride * 8 * y;
+
+ src = ctx->prev_frame_buf + base_offset;
+ dst = ctx->cur_frame_buf + base_offset;
+
+ for (x = 0; x < ctx->num_hblocks_y; x++) {
+
+ /* Check for a change condition in the current block. */
+
+ if (is_pframe)
+ bit = _read_bits(ctx, 1);
+ else
+ bit = 0;
+
+ if (bit == 0) {
+
+ /* Yes: Is the new content the same as it was in one of
+ * the 15 last frames preceding the previous? */
+
+ if (is_pframe)
+ bit = _read_bits(ctx, 1);
+
+ if (bit == 0) {
+
+ /* No: decode it. */
+
+ if (_vlc_decode_block(ctx, dct_block, ctx->num_coeffs) == FALSE) {
+
+ return FALSE;
+ }
+
+ _idct_dequant_block(ctx, dct_block, 0);
+
+ bptr = dct_block;
+ for (i = 0; i < 8; i++) {
+ offset = ctx->y_stride * i;
+
+ for (j = 0; j < 8; j++) {
+ guint v;
+
+ if (bptr[j] <= 255)
+ v = (bptr[j] >= 0) ? bptr[j] : 0;
+ else
+ v = 255;
+
+ *(dst + offset + j) = v;
+ }
+
+ bptr += 8;
+ }
+ } else {
+ guint32 backref;
+
+ /* Yes: read the backreference (4 bits) and copy. */
+
+ backref = _read_bits(ctx, 4);
+
+ p = ctx->buf_ptrs[(ctx->ptr_index + backref) % 16];
+ p += base_offset + (x * 8);
+
+ for (i = 0; i < 8; i++) {
+ offset = ctx->y_stride * i;
+
+ memcpy(dst + offset, p + offset, 8);
+ }
+ }
+ } else {
+
+ /* No change no worries: just copy from the previous frame. */
+
+ for (i = 0; i < 8; i++) {
+ offset = ctx->y_stride * i;
+
+ memcpy(dst + offset, src + offset, 8);
+ }
+ }
+
+ src += 8;
+ dst += 8;
+ }
+ }
+
+ /*
+ * Decode Cr and Cb planes.
+ */
+ for (chrom_ch = 0; chrom_ch < 2; chrom_ch++) {
+
+ base_offset = ctx->y_size + (ctx->crcb_size * chrom_ch);
+
+ for (y = 0; y < ctx->num_vblocks_cbcr; y++) {
+ guint num_rows = 8;
+
+ /* The last row of blocks in chrominance for 160x120 resolution
+ * is half the normal height and must be accounted for. */
+ if (y + 1 == ctx->num_vblocks_cbcr && ctx->frame_height % 16 != 0)
+ num_rows = 4;
+
+ offset = base_offset + (ctx->crcb_stride * 8 * y);
+
+ src = ctx->prev_frame_buf + offset;
+ dst = ctx->cur_frame_buf + offset;
+
+ for (x = 0; x < ctx->num_hblocks_cbcr; x++) {
+
+ /* Check for a change condition in the current block. */
+
+ if (is_pframe)
+ bit = _read_bits(ctx, 1);
+ else
+ bit = 1;
+
+ if (bit == 1) {
+
+ /* Yes: decode it. */
+
+ if (_vlc_decode_block(ctx, dct_block, ctx->num_coeffs) == FALSE) {
+
+ /* Corrupted frame: clear Cr and Cb planes and return. */
+ p = ctx->cur_frame_buf + ctx->y_size;
+ memset(p, 128, ctx->crcb_size * 2);
+
+ return FALSE;
+ }
+
+ _idct_dequant_block(ctx, dct_block, 1);
+
+ for (i = 0; i < num_rows; i++) {
+ p = dst + (ctx->crcb_stride * i);
+
+ for (j = 0; j < 8; j++)
+ p[j] = dct_block[(i * 8) + j];
+ }
+
+ } else {
+
+ /* No change no worries: just copy from the previous frame. */
+
+ for (i = 0; i < num_rows; i++) {
+ offset = ctx->crcb_stride * i;
+
+ memcpy(dst + offset, src + offset, 8);
+ }
+ }
+
+ src += 8;
+ dst += 8;
+ }
+ }
+ }
+
+ /*
+ * Make a copy of the current frame and store in
+ * the circular pointer list of 16 entries.
+ */
+ ctx->prev_frame_buf = ctx->buf_ptrs[ctx->ptr_index];
+ memcpy(ctx->prev_frame_buf, ctx->cur_frame_buf,
+ ctx->y_size + (ctx->crcb_size * 2));
+
+ if (--ctx->ptr_index < 0)
+ ctx->ptr_index = 15;
+
+ /*
+ * Perform deblocking on all planes.
+ */
+ _deblock(ctx->cur_frame_buf,
+ ctx->y_stride, ctx->y_row_count);
+
+ _deblock(ctx->cur_frame_buf + ctx->y_size,
+ ctx->crcb_stride, ctx->crcb_row_count);
+
+ _deblock(ctx->cur_frame_buf + ctx->y_size + ctx->crcb_size,
+ ctx->crcb_stride, ctx->crcb_row_count);
+
+ return TRUE;
+}
+
generated by cgit v1.2.1 (git 2.18.0) at 2024-12-29 13:04:45 +0000