Implement YOP demuxer and video decoder.

Patch by Mohamed Naufal gmailify(naufal11).

Originally committed as revision 22724 to svn://svn.ffmpeg.org/ffmpeg/trunk

1 files changed, 260 insertions, 0 deletions

diff --git a/libavcodec/yop.c b/libavcodec/yop.c
new file mode 100644
index 0000000000..235e5c9658
--- /dev/null
+++ b/libavcodec/yop.c
@@ -0,0 +1,260 @@
+/**
+ * @file libavcodec/yop.c
+ * Psygnosis YOP decoder
+ *
+ * Copyright (C) 2010 Mohamed Naufal Basheer <naufal11@gmail.com>
+ * derived from the code by
+ * Copyright (C) 2009 Thomas P. Higdon <thomas.p.higdon@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 "libavutil/intreadwrite.h"
+
+#include "avcodec.h"
+#include "get_bits.h"
+
+typedef struct YopDecContext {
+    AVFrame frame;
+    AVCodecContext *avctx;
+
+    int num_pal_colors;
+    int first_color[2];
+    int frame_data_length;
+    int row_pos;
+
+    uint8_t *low_nibble;
+    uint8_t *srcptr;
+    uint8_t *dstptr;
+    uint8_t *dstbuf;
+} YopDecContext;
+
+// These tables are taken directly from:
+// http://wiki.multimedia.cx/index.php?title=Psygnosis_YOP
+
+/**
+ * Lookup table for painting macroblocks. Bytes 0-2 of each entry contain
+ * the macroblock positions to be painted (taken as (0, B0, B1, B2)).
+ * Byte 3 contains the number of bytes consumed on the input,
+ * equal to max(bytes 0-2) + 1.
+ */
+static const uint8_t paint_lut[15][4] =
+    {{1, 2, 3, 4}, {1, 2, 0, 3},
+     {1, 2, 1, 3}, {1, 2, 2, 3},
+     {1, 0, 2, 3}, {1, 0, 0, 2},
+     {1, 0, 1, 2}, {1, 1, 2, 3},
+     {0, 1, 2, 3}, {0, 1, 0, 2},
+     {1, 1, 0, 2}, {0, 1, 1, 2},
+     {0, 0, 1, 2}, {0, 0, 0, 1},
+     {1, 1, 1, 2},
+    };
+
+/**
+ * Lookup table for copying macroblocks. Each entry contains the respective
+ * x and y pixel offset for the copy source.
+ */
+static const int8_t motion_vector[16][2] =
+    {{-4, -4}, {-2, -4},
+     { 0, -4}, { 2, -4},
+     {-4, -2}, {-4,  0},
+     {-3, -3}, {-1, -3},
+     { 1, -3}, { 3, -3},
+     {-3, -1}, {-2, -2},
+     { 0, -2}, { 2, -2},
+     { 4, -2}, {-2,  0},
+    };
+
+static av_cold int yop_decode_init(AVCodecContext *avctx)
+{
+    YopDecContext *s = avctx->priv_data;
+    s->avctx = avctx;
+
+    if (avctx->width & 1 || avctx->height & 1 ||
+        avcodec_check_dimensions(avctx, avctx->width, avctx->height) < 0) {
+        av_log(avctx, AV_LOG_ERROR, "YOP has invalid dimensions\n");
+        return -1;
+    }
+
+    avctx->pix_fmt = PIX_FMT_PAL8;
+
+    s->num_pal_colors = avctx->extradata[0];
+    s->first_color[0] = avctx->extradata[1];
+    s->first_color[1] = avctx->extradata[2];
+
+    if (s->num_pal_colors + s->first_color[0] > 256 ||
+        s->num_pal_colors + s->first_color[1] > 256) {
+        av_log(avctx, AV_LOG_ERROR,
+               "YOP: palette parameters invalid, header probably corrupt\n");
+        return AVERROR_INVALIDDATA;
+    }
+
+    return 0;
+}
+
+static av_cold int yop_decode_close(AVCodecContext *avctx)
+{
+    YopDecContext *s = avctx->priv_data;
+    if (s->frame.data[0])
+        avctx->release_buffer(avctx, &s->frame);
+    return 0;
+}
+
+/**
+ * Paints a macroblock using the pattern in paint_lut.
+ * @param s codec context
+ * @param tag the tag that was in the nibble
+ */
+static void yop_paint_block(YopDecContext *s, int tag)
+{
+    s->dstptr[0]                        = s->srcptr[0];
+    s->dstptr[1]                        = s->srcptr[paint_lut[tag][0]];
+    s->dstptr[s->frame.linesize[0]]     = s->srcptr[paint_lut[tag][1]];
+    s->dstptr[s->frame.linesize[0] + 1] = s->srcptr[paint_lut[tag][2]];
+
+    // The number of src bytes consumed is in the last part of the lut entry.
+    s->srcptr += paint_lut[tag][3];
+}
+
+/**
+ * Copies a previously painted macroblock to the current_block.
+ * @param copy_tag the tag that was in the nibble
+ */
+static int yop_copy_previous_block(YopDecContext *s, int copy_tag)
+{
+    uint8_t *bufptr;
+
+    // Calculate position for the copy source
+    bufptr = s->dstptr + motion_vector[copy_tag][0] +
+             s->frame.linesize[0] * motion_vector[copy_tag][1];
+    if (bufptr < s->dstbuf) {
+        av_log(s->avctx, AV_LOG_ERROR,
+               "YOP: cannot decode, file probably corrupt\n");
+        return AVERROR_INVALIDDATA;
+    }
+
+    s->dstptr[0]                        = bufptr[0];
+    s->dstptr[1]                        = bufptr[1];
+    s->dstptr[s->frame.linesize[0]]     = bufptr[s->frame.linesize[0]];
+    s->dstptr[s->frame.linesize[0] + 1] = bufptr[s->frame.linesize[0] + 1];
+
+    return 0;
+}
+
+/**
+ * Returns the next nibble in sequence, consuming a new byte on the input
+ * only if necessary.
+ */
+static uint8_t yop_get_next_nibble(YopDecContext *s)
+{
+    int ret;
+
+    if (s->low_nibble) {
+        ret           = *s->low_nibble & 0xf;
+        s->low_nibble = NULL;
+    }else {
+        s->low_nibble = s->srcptr++;
+        ret           = *s->low_nibble >> 4;
+    }
+    return ret;
+}
+
+/**
+ * Takes s->dstptr to the next macroblock in sequence.
+ */
+static void yop_next_macroblock(YopDecContext *s)
+{
+    // If we are advancing to the next row of macroblocks
+    if (s->row_pos == s->frame.linesize[0] - 2) {
+        s->dstptr  += s->frame.linesize[0];
+        s->row_pos =  0;
+    }else {
+        s->row_pos += 2;
+    }
+    s->dstptr += 2;
+}
+
+static int yop_decode_frame(AVCodecContext *avctx, void *data, int *data_size,
+                            AVPacket *avpkt)
+{
+    YopDecContext *s = avctx->priv_data;
+    int tag, firstcolor, is_odd_frame;
+    int ret, i;
+    uint32_t *palette;
+
+    if (s->frame.data[0])
+        avctx->release_buffer(avctx, &s->frame);
+
+    ret = avctx->get_buffer(avctx, &s->frame);
+    if (ret < 0) {
+        av_log(avctx, AV_LOG_ERROR, "get_buffer() failed\n");
+        return ret;
+    }
+
+    s->frame.linesize[0] = avctx->width;
+
+    s->dstbuf     = s->frame.data[0];
+    s->dstptr     = s->frame.data[0];
+    s->srcptr     = avpkt->data + 4;
+    s->row_pos    = 0;
+    s->low_nibble = NULL;
+
+    is_odd_frame = avpkt->data[0];
+    firstcolor   = s->first_color[is_odd_frame];
+    palette      = (uint32_t *)s->frame.data[1];
+
+    for (i = 0; i < s->num_pal_colors; i++, s->srcptr += 3)
+        palette[i + firstcolor] = (s->srcptr[0] << 18) |
+                                  (s->srcptr[1] << 10) |
+                                  (s->srcptr[2] << 2);
+
+    s->frame.palette_has_changed = 1;
+
+    while (s->dstptr - s->dstbuf <
+           avctx->width * avctx->height &&
+           s->srcptr - avpkt->data < avpkt->size) {
+
+        tag = yop_get_next_nibble(s);
+
+        if (tag != 0xf) {
+            yop_paint_block(s, tag);
+        }else {
+            tag = yop_get_next_nibble(s);
+            ret = yop_copy_previous_block(s, tag);
+            if (ret < 0) {
+                avctx->release_buffer(avctx, &s->frame);
+                return ret;
+            }
+        }
+        yop_next_macroblock(s);
+    }
+
+    *data_size        = sizeof(AVFrame);
+    *(AVFrame *) data = s->frame;
+    return avpkt->size;
+}
+
+AVCodec yop_decoder = {
+    "yop",
+    CODEC_TYPE_VIDEO,
+    CODEC_ID_YOP,
+    sizeof(YopDecContext),
+    yop_decode_init,
+    NULL,
+    yop_decode_close,
+    yop_decode_frame,
+    .long_name = NULL_IF_CONFIG_SMALL("Psygnosis YOP Video"),
+};