ffmpeg-2.1.1: move directory

git-svn-id: svn://kolibrios.org@6148 a494cfbc-eb01-0410-851d-a64ba20cac60

contrib/sdk/sources/ffmpeg/ffmpeg-2.1/libavcodec/rtjpeg.c

@@ -0,0 +1,176 @@
+/*
+ * RTJpeg decoding functions
+ * Copyright (c) 2006 Reimar Doeffinger
+ *
+ * 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 "libavutil/common.h"
+#include "get_bits.h"
+#include "rtjpeg.h"
+
+#define PUT_COEFF(c) \
+    i = scan[coeff--]; \
+    block[i] = (c) * quant[i];
+
+/// aligns the bitstream to the given power of two
+#define ALIGN(a) \
+    n = (-get_bits_count(gb)) & (a - 1); \
+    if (n) {skip_bits(gb, n);}
+
+/**
+ * @brief read one block from stream
+ * @param gb contains stream data
+ * @param block where data is written to
+ * @param scan array containing the mapping stream address -> block position
+ * @param quant quantization factors
+ * @return 0 means the block is not coded, < 0 means an error occurred.
+ *
+ * Note: GetBitContext is used to make the code simpler, since all data is
+ * aligned this could be done faster in a different way, e.g. as it is done
+ * in MPlayer libmpcodecs/native/rtjpegn.c.
+ */
+static inline int get_block(GetBitContext *gb, int16_t *block, const uint8_t *scan,
+                            const uint32_t *quant) {
+    int coeff, i, n;
+    int8_t ac;
+    uint8_t dc = get_bits(gb, 8);
+
+    // block not coded
+    if (dc == 255)
+       return 0;
+
+    // number of non-zero coefficients
+    coeff = get_bits(gb, 6);
+    if (get_bits_left(gb) < (coeff << 1))
+        return AVERROR_INVALIDDATA;
+
+    // normally we would only need to clear the (63 - coeff) last values,
+    // but since we do not know where they are we just clear the whole block
+    memset(block, 0, 64 * sizeof(int16_t));
+
+    // 2 bits per coefficient
+    while (coeff) {
+        ac = get_sbits(gb, 2);
+        if (ac == -2)
+            break; // continue with more bits
+        PUT_COEFF(ac);
+    }
+
+    // 4 bits per coefficient
+    ALIGN(4);
+    if (get_bits_left(gb) < (coeff << 2))
+        return AVERROR_INVALIDDATA;
+    while (coeff) {
+        ac = get_sbits(gb, 4);
+        if (ac == -8)
+            break; // continue with more bits
+        PUT_COEFF(ac);
+    }
+
+    // 8 bits per coefficient
+    ALIGN(8);
+    if (get_bits_left(gb) < (coeff << 3))
+        return AVERROR_INVALIDDATA;
+    while (coeff) {
+        ac = get_sbits(gb, 8);
+        PUT_COEFF(ac);
+    }
+
+    PUT_COEFF(dc);
+    return 1;
+}
+
+/**
+ * @brief decode one rtjpeg YUV420 frame
+ * @param c context, must be initialized via ff_rtjpeg_decode_init
+ * @param f AVFrame to place decoded frame into. If parts of the frame
+ *          are not coded they are left unchanged, so consider initializing it
+ * @param buf buffer containing input data
+ * @param buf_size length of input data in bytes
+ * @return number of bytes consumed from the input buffer
+ */
+int ff_rtjpeg_decode_frame_yuv420(RTJpegContext *c, AVFrame *f,
+                                  const uint8_t *buf, int buf_size) {
+    GetBitContext gb;
+    int w = c->w / 16, h = c->h / 16;
+    int x, y, ret;
+    uint8_t *y1 = f->data[0], *y2 = f->data[0] + 8 * f->linesize[0];
+    uint8_t *u = f->data[1], *v = f->data[2];
+
+    if ((ret = init_get_bits8(&gb, buf, buf_size)) < 0)
+        return ret;
+
+    for (y = 0; y < h; y++) {
+        for (x = 0; x < w; x++) {
+#define BLOCK(quant, dst, stride) do { \
+    int res = get_block(&gb, block, c->scan, quant); \
+    if (res < 0) \
+        return res; \
+    if (res > 0) \
+        c->dsp->idct_put(dst, stride, block); \
+} while (0)
+            int16_t *block = c->block;
+            BLOCK(c->lquant, y1, f->linesize[0]);
+            y1 += 8;
+            BLOCK(c->lquant, y1, f->linesize[0]);
+            y1 += 8;
+            BLOCK(c->lquant, y2, f->linesize[0]);
+            y2 += 8;
+            BLOCK(c->lquant, y2, f->linesize[0]);
+            y2 += 8;
+            BLOCK(c->cquant, u,  f->linesize[1]);
+            u += 8;
+            BLOCK(c->cquant, v,  f->linesize[2]);
+            v += 8;
+        }
+        y1 += 2 * 8 * (f->linesize[0] - w);
+        y2 += 2 * 8 * (f->linesize[0] - w);
+        u += 8 * (f->linesize[1] - w);
+        v += 8 * (f->linesize[2] - w);
+    }
+    return get_bits_count(&gb) / 8;
+}
+
+/**
+ * @brief initialize an RTJpegContext, may be called multiple times
+ * @param c context to initialize
+ * @param dsp specifies the idct to use for decoding
+ * @param width width of image, will be rounded down to the nearest multiple
+ *              of 16 for decoding
+ * @param height height of image, will be rounded down to the nearest multiple
+ *              of 16 for decoding
+ * @param lquant luma quantization table to use
+ * @param cquant chroma quantization table to use
+ */
+void ff_rtjpeg_decode_init(RTJpegContext *c, DSPContext *dsp,
+                           int width, int height,
+                           const uint32_t *lquant, const uint32_t *cquant) {
+    int i;
+    c->dsp = dsp;
+    for (i = 0; i < 64; i++) {
+        int z = ff_zigzag_direct[i];
+        int p = c->dsp->idct_permutation[i];
+        z = ((z << 3) | (z >> 3)) & 63; // rtjpeg uses a transposed variant
+
+        // permute the scan and quantization tables for the chosen idct
+        c->scan[i] = c->dsp->idct_permutation[z];
+        c->lquant[p] = lquant[i];
+        c->cquant[p] = cquant[i];
+    }
+    c->w = width;
+    c->h = height;
+}