diff options
Diffstat (limited to 'kopete/protocols/msn/webcam/libmimic/encode.c')
-rw-r--r-- | kopete/protocols/msn/webcam/libmimic/encode.c | 419 |
1 files changed, 419 insertions, 0 deletions
diff --git a/kopete/protocols/msn/webcam/libmimic/encode.c b/kopete/protocols/msn/webcam/libmimic/encode.c new file mode 100644 index 00000000..6c8a9de8 --- /dev/null +++ b/kopete/protocols/msn/webcam/libmimic/encode.c @@ -0,0 +1,419 @@ +/* Copyright (C) 2005 Ole André Vadla Ravnås <[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 <stdlib.h> +#include <string.h> +#include <math.h> +#include "mimic-private.h" + +#define LUMINANCE_THRESHOLD 32.0f +#define CHROMINANCE_THRESHOLD 36.0f + +static void encode_main(MimCtx *ctx, guchar *out_buf, gboolean is_pframe); + +/** + * Encode a MIMIC-encoded frame from RGB data. + * + * @param ctx the mimic context + * @param input_buffer buffer containing pixeldata in RGB 24-bpp packed pixel top-down format + * @param output_buffer buffer that will receive the MIMIC-encoded frame + * (use #mimic_get_property to determine the required buffer size) + * @param output_length pointer to an integer that receives the length of the encoded data + * written to output_buffer + * @param make_keyframe whether the encoder should make this frame a keyframe + * @returns #TRUE on success + */ +gboolean mimic_encode_frame(MimCtx *ctx, + const guchar *input_buffer, + guchar *output_buffer, + gint *output_length, + gboolean make_keyframe) +{ + guchar *output_y, *output_cb, *output_cr; + + /* + * Some sanity checks. + */ + if (ctx == NULL || input_buffer == NULL || + output_buffer == NULL || output_length == NULL) + { + return FALSE; + } + + if (!ctx->encoder_initialized) + return FALSE; + + /* + * Initialize state. + */ + ctx->chunk_ptr = (guint32 *) (output_buffer + 20); + ctx->cur_chunk = 0; + ctx->cur_chunk_len = 0; + + if (ctx->frame_num == 0) + make_keyframe = TRUE; + + /* + * Write header. + */ + memset(output_buffer, 0, 20); + *((guint16 *) (output_buffer + 0)) = GUINT16_TO_LE(256); + *((guint16 *) (output_buffer + 2)) = GUINT16_TO_LE(ctx->quality); + *((guint16 *) (output_buffer + 4)) = GUINT16_TO_LE(ctx->frame_width); + *((guint16 *) (output_buffer + 6)) = GUINT16_TO_LE(ctx->frame_height); + *((guint32 *) (output_buffer + 12)) = GUINT32_TO_LE((make_keyframe == 0)); + *(output_buffer + 16) = ctx->num_coeffs; + *(output_buffer + 17) = 0; + + /* + * Perform RGB to YUV 420 conversion. + */ + output_y = ctx->cur_frame_buf; + output_cr = ctx->cur_frame_buf + ctx->y_size; + output_cb = ctx->cur_frame_buf + ctx->y_size + ctx->crcb_size; + + _rgb_to_yuv(input_buffer, + output_y, + output_cb, + output_cr, + ctx->frame_width, + ctx->frame_height); + + /* + * Encode frame. + */ + encode_main(ctx, output_buffer, (make_keyframe == FALSE)); + + /* + * Write out any pending bits to stream by zero-padding with 32 bits. + */ + _write_bits(ctx, 0, 32); + + /* + * Calculate bytes written. + */ + *output_length = (guchar *) ctx->chunk_ptr - output_buffer; + + /* + * Increment frame counter. + */ + ctx->frame_num++; + + return TRUE; +} + +static gdouble compare_blocks(const guchar *p1, + const guchar *p2, + gint stride, + gint row_count, + gboolean is_chrom); + +/* + * encode_main + * + * Main encoding loop. + */ +static void encode_main(MimCtx *ctx, guchar *out_buf, gboolean is_pframe) +{ + gint x, y, i, offset, chrom_ch; + gint dct_block[64]; + guchar *src, *dst, *p1, *p2; + gdouble match; + gboolean encoded; + + /* + * Round down small differences in luminance channel. + */ + if (is_pframe) { + + p1 = ctx->cur_frame_buf; + p2 = ctx->prev_frame_buf; + + for (i = 0; i < ctx->y_size; i++) { + + if (abs(p2[0] - p1[0]) < 7) + p1[0] = p2[0]; + + p1++; + p2++; + } + } + + /* + * Encode Y plane. + */ + for (y = 0; y < ctx->num_vblocks_y; y++) { + + for (x = 0; x < ctx->num_hblocks_y; x++) { + + /* Calculate final offset into buffer. */ + offset = (ctx->y_stride * 8 * y) + (x * 8); + + src = NULL; + encoded = FALSE; + + if (is_pframe) { + + /* Is the current block similar enough to what it was in the previous frame? */ + + match = compare_blocks(ctx->cur_frame_buf + offset, + ctx->prev_frame_buf + offset, + ctx->y_stride, 8, + FALSE); + + if (match > LUMINANCE_THRESHOLD) { + + /* Yes: write out '1' to indicate a no-change condition. */ + + _write_bits(ctx, 1, 1); + + src = ctx->prev_frame_buf + offset; + encoded = TRUE; + + } else { + + /* No: Is the current block similar enough to what it was in one + * of the (up to) 15 last frames preceding the previous? */ + + gint best_index = 0; + gdouble best_match = 0.0; + + gint num_backrefs = ctx->frame_num - 1; + if (num_backrefs > 15) + num_backrefs = 15; + + for (i = 1; i <= num_backrefs; i++) { + + match = compare_blocks(ctx->buf_ptrs[(ctx->ptr_index + i) % 16] + offset, + ctx->cur_frame_buf + offset, + ctx->y_stride, 8, + FALSE); + + if (match > LUMINANCE_THRESHOLD && match > best_match) { + best_index = i; + best_match = match; + } + + } + + if (best_index != 0) { + + /* Yes: write out '01' to indicate a "change but like previous"-condition, + * followed by 4 bits containing the back-reference. */ + _write_bits(ctx, 0, 1); + _write_bits(ctx, 1, 1); + _write_bits(ctx, best_index, 4); + + src = ctx->buf_ptrs[(ctx->ptr_index + best_index) % 16] + offset; + encoded = TRUE; + + } + } + } + + if (!encoded) { + + /* Keyframe or in any case no? ;-) Well, encode it then. */ + + if (is_pframe) { + _write_bits(ctx, 0, 1); + _write_bits(ctx, 0, 1); + } + + _fdct_quant_block(ctx, + dct_block, + ctx->cur_frame_buf + offset, + ctx->y_stride, + FALSE, + ctx->num_coeffs); + + _vlc_encode_block(ctx, + dct_block, + ctx->num_coeffs); + + } + + /* And if there was some kind of no-change condition, + * we want to copy the previous block. */ + if (src != NULL) { + + dst = ctx->cur_frame_buf + offset; + for (i = 0; i < 8; i++) { + + memcpy(dst, src, 8); + + src += ctx->y_stride; + dst += ctx->y_stride; + } + + } + + } + + } + + /* + * Encode Cr and Cb planes. + */ + for (chrom_ch = 0; chrom_ch < 2; chrom_ch++) { + + /* Calculate base offset into buffer. */ + gint base_offset = ctx->y_size + (ctx->crcb_size * chrom_ch); + + for (y = 0; y < ctx->num_vblocks_cbcr; y++) { + guchar tmp_block[64]; + 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; + + for (x = 0; x < ctx->num_hblocks_cbcr; x++) { + + /* Calculate final offset into buffer. */ + offset = base_offset + (ctx->crcb_stride * 8 * y) + (x * 8); + + src = NULL; + encoded = FALSE; + + if (is_pframe) { + + /* Is the current block similar enough to what it was in the previous frame? */ + + match = compare_blocks(ctx->prev_frame_buf + offset, + ctx->cur_frame_buf + offset, + ctx->crcb_stride, num_rows, + TRUE); + + if (match > CHROMINANCE_THRESHOLD) { + + /* Yes: write out '0' to indicate a no-change condition. */ + + _write_bits(ctx, 0, 1); + + encoded = TRUE; + + src = ctx->prev_frame_buf + offset; + dst = ctx->cur_frame_buf + offset; + for (i = 0; i < num_rows; i++) { + + memcpy(dst, src, 8); + + src += ctx->crcb_stride; + dst += ctx->crcb_stride; + } + } + + } + + if (!encoded) { + + /* Keyframe or just not similar enough? ;-) Well, encode it then. */ + + if (is_pframe) + _write_bits(ctx, 1, 1); + + /* Use a temporary array to handle cases where the + * current block is not of normal height (see above). */ + src = ctx->cur_frame_buf + offset; + dst = tmp_block; + for (i = 0; i < 8; i++) { + + memcpy(dst, src, 8); + + if (i < (num_rows - 1)) + src += ctx->crcb_stride; + dst += 8; + } + + _fdct_quant_block(ctx, + dct_block, + tmp_block, + 8, + TRUE, + ctx->num_coeffs); + + _vlc_encode_block(ctx, + dct_block, + ctx->num_coeffs); + + } + + } + + } + + } + + /* + * 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; +} + +/* + * compare_blocks + * + * Helper-function used to compare two blocks and + * determine how similar they are. + */ +static gdouble compare_blocks(const guchar *p1, + const guchar *p2, + gint stride, + gint row_count, + gboolean is_chrom) +{ + gint i, j, sum; + gdouble d; + + sum = 0; + + for (i = 0; i < row_count; i++) { + + for (j = 0; j < 8; j++) { + + gint d = p2[j] - p1[j]; + + sum += d * d; + } + + p1 += stride; + p2 += stride; + } + + if (is_chrom) { + if (row_count == 8) + d = sum * 0.015625; + else + d = sum * 0.03125; + } else { + d = sum / 64; + } + + if (d == 0.0f) + return 100.0f; + else + return (10.0f * log(65025.0f / d)) / G_LN10; +} + |