NuppelVideo/MythTVVideo support, including rtjpeg decoder

Originally committed as revision 5232 to svn://svn.ffmpeg.org/ffmpeg/trunk

1 files changed, 162 insertions, 0 deletions

diff --git a/libavcodec/rtjpeg.c b/libavcodec/rtjpeg.c
new file mode 100644
index 0000000000..ebf10886b4
--- /dev/null
+++ b/libavcodec/rtjpeg.c
@@ -0,0 +1,162 @@
+/*
+ * RTJpeg decoding functions
+ * Copyright (c) 2006 Reimar Doeffinger
+ *
+ * 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 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 "common.h"
+#include "bitstream.h"
+#include "dsputil.h"
+#include "rtjpeg.h"
+
+#define PUT_COEFF(c) \
+    i = scan[coeff--]; \
+    block[i] = (c) * quant[i];
+
+//! aligns the bitstream to the give 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
+ *
+ * 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, DCTELEM *block, uint8_t *scan,
+                            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);
+    // 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(DCTELEM));
+
+    // 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);
+    while (coeff) {
+        ac = get_sbits(gb, 4);
+        if (ac == -8)
+            break; // continue with more bits
+        PUT_COEFF(ac);
+    }
+
+    // 8 bits per coefficient
+    ALIGN(8);
+    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 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 rtjpeg_decode_frame_yuv420(RTJpegContext *c, AVFrame *f,
+                               uint8_t *buf, int buf_size) {
+    GetBitContext gb;
+    int w = c->w / 16, h = c->h / 16;
+    int x, y;
+    void *y1 = f->data[0], *y2 = f->data[0] + 8 * f->linesize[0];
+    void *u = f->data[1], *v = f->data[2];
+    init_get_bits(&gb, buf, buf_size * 8);
+    for (y = 0; y < h; y++) {
+        for (x = 0; x < w; x++) {
+            if (get_block(&gb, c->block, c->scan, c->lquant))
+                c->dsp->idct_put(y1, f->linesize[0], c->block);
+            y1 += 8;
+            if (get_block(&gb, c->block, c->scan, c->lquant))
+                c->dsp->idct_put(y1, f->linesize[0], c->block);
+            y1 += 8;
+            if (get_block(&gb, c->block, c->scan, c->lquant))
+                c->dsp->idct_put(y2, f->linesize[0], c->block);
+            y2 += 8;
+            if (get_block(&gb, c->block, c->scan, c->lquant))
+                c->dsp->idct_put(y2, f->linesize[0], c->block);
+            y2 += 8;
+            if (get_block(&gb, c->block, c->scan, c->cquant))
+                c->dsp->idct_put(u, f->linesize[1], c->block);
+            u += 8;
+            if (get_block(&gb, c->block, c->scan, c->cquant))
+                c->dsp->idct_put(v, f->linesize[2], c->block);
+            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 rtjpeg_decode_init(RTJpegContext *c, DSPContext *dsp,
+                        int width, int height,
+                        uint32_t *lquant, 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;
+}