lavc: add xface image decoder and encoder

Based on libcompface code by James Ashton <James.Ashton@anu.edu.au>, and
relicensed to LGPL with the author's consent.

1 files changed, 237 insertions, 0 deletions

diff --git a/libavcodec/xfaceenc.c b/libavcodec/xfaceenc.c
new file mode 100644
index 0000000000..db63f59cfb
--- /dev/null
+++ b/libavcodec/xfaceenc.c
@@ -0,0 +1,237 @@
+/*
+ * Copyright (c) 1990 James Ashton - Sydney University
+ * Copyright (c) 2012 Stefano Sabatini
+ *
+ * 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
+ */
+
+/**
+ * @file
+ * X-Face encoder, based on libcompface, by James Ashton.
+ */
+
+#include "xface.h"
+#include "avcodec.h"
+#include "internal.h"
+
+typedef struct XFaceContext {
+    AVClass *class;
+    uint8_t bitmap[XFACE_PIXELS]; ///< image used internally for decoding
+    int max_line_len;             ///< max line length for compressed data
+    int set_header;               ///< set X-Face header in the output
+} XFaceContext;
+
+static int all_same(char *bitmap, int w, int h)
+{
+    char val, *row;
+    int x;
+
+    val = *bitmap;
+    while (h--) {
+        row = bitmap;
+        x = w;
+        while (x--)
+            if (*(row++) != val)
+                return 0;
+        bitmap += XFACE_WIDTH;
+    }
+    return 1;
+}
+
+static int all_black(char *bitmap, int w, int h)
+{
+    if (w > 3) {
+        w /= 2;
+        h /= 2;
+        return (all_black(bitmap, w, h) && all_black(bitmap + w, w, h) &&
+                all_black(bitmap + XFACE_WIDTH * h, w, h) &&
+                all_black(bitmap + XFACE_WIDTH * h + w, w, h));
+    } else {
+        /* at least one pixel in the 2x2 grid is non-zero */
+        return *bitmap || *(bitmap + 1) ||
+               *(bitmap + XFACE_WIDTH) || *(bitmap + XFACE_WIDTH + 1);
+    }
+}
+
+static int all_white(char *bitmap, int w, int h)
+{
+    return *bitmap == 0 && all_same(bitmap, w, h);
+}
+
+typedef struct {
+    const ProbRange *prob_ranges[XFACE_PIXELS*2];
+    int prob_ranges_idx;
+} ProbRangesQueue;
+
+static inline int pq_push(ProbRangesQueue *pq, const ProbRange *p)
+{
+    if (pq->prob_ranges_idx >= XFACE_PIXELS * 2 - 1)
+        return -1;
+    pq->prob_ranges[pq->prob_ranges_idx++] = p;
+    return 0;
+}
+
+static void push_greys(ProbRangesQueue *pq, char *bitmap, int w, int h)
+{
+    if (w > 3) {
+        w /= 2;
+        h /= 2;
+        push_greys(pq, bitmap,                       w, h);
+        push_greys(pq, bitmap + w,                   w, h);
+        push_greys(pq, bitmap + XFACE_WIDTH * h,     w, h);
+        push_greys(pq, bitmap + XFACE_WIDTH * h + w, w, h);
+    } else {
+        const ProbRange *p = ff_xface_probranges_2x2 +
+                 *bitmap +
+            2 * *(bitmap + 1) +
+            4 * *(bitmap + XFACE_WIDTH) +
+            8 * *(bitmap + XFACE_WIDTH + 1);
+        pq_push(pq, p);
+    }
+}
+
+static void encode_block(char *bitmap, int w, int h, int level, ProbRangesQueue *pq)
+{
+    if (all_white(bitmap, w, h)) {
+        pq_push(pq, &ff_xface_probranges_per_level[level][XFACE_COLOR_WHITE]);
+    } else if (all_black(bitmap, w, h)) {
+        pq_push(pq, &ff_xface_probranges_per_level[level][XFACE_COLOR_BLACK]);
+        push_greys(pq, bitmap, w, h);
+    } else {
+        pq_push(pq, &ff_xface_probranges_per_level[level][XFACE_COLOR_GREY]);
+        w /= 2;
+        h /= 2;
+        level++;
+        encode_block(bitmap,                       w, h, level, pq);
+        encode_block(bitmap + w,                   w, h, level, pq);
+        encode_block(bitmap + h * XFACE_WIDTH,     w, h, level, pq);
+        encode_block(bitmap + w + h * XFACE_WIDTH, w, h, level, pq);
+    }
+}
+
+static av_cold int xface_encode_init(AVCodecContext *avctx)
+{
+    avctx->coded_frame = avcodec_alloc_frame();
+    if (!avctx->coded_frame)
+        return AVERROR(ENOMEM);
+    avctx->coded_frame->pict_type = AV_PICTURE_TYPE_I;
+
+    return 0;
+}
+
+static void push_integer(BigInt *b, const ProbRange *prange)
+{
+    uint8_t r;
+
+    ff_big_div(b, prange->range, &r);
+    ff_big_mul(b, 0);
+    ff_big_add(b, r + prange->offset);
+}
+
+static int xface_encode_frame(AVCodecContext *avctx, AVPacket *pkt,
+                              const AVFrame *frame, int *got_packet)
+{
+    XFaceContext *xface = avctx->priv_data;
+    ProbRangesQueue pq = {{ 0 }, 0};
+    uint8_t bitmap_copy[XFACE_PIXELS];
+    BigInt b = {0};
+    int i, j, k, ret = 0;
+    const uint8_t *buf;
+    uint8_t *p;
+    char intbuf[XFACE_MAX_DIGITS];
+
+    if (avctx->width || avctx->height) {
+        if (avctx->width != XFACE_WIDTH || avctx->height != XFACE_HEIGHT) {
+            av_log(avctx, AV_LOG_ERROR,
+                   "Size value %dx%d not supported, only accepts a size of %dx%d\n",
+                   avctx->width, avctx->height, XFACE_WIDTH, XFACE_HEIGHT);
+            return AVERROR(EINVAL);
+        }
+    }
+    avctx->width  = XFACE_WIDTH;
+    avctx->height = XFACE_HEIGHT;
+
+    /* convert image from MONOWHITE to 1=black 0=white bitmap */
+    buf = frame->data[0];
+    for (i = 0, j = 0; i < XFACE_PIXELS; ) {
+        for (k = 0; k < 8; k++)
+            xface->bitmap[i++] = (buf[j]>>(7-k))&1;
+        if (++j == XFACE_WIDTH/8) {
+            buf += frame->linesize[0];
+            j = 0;
+        }
+    }
+
+    /* create a copy of bitmap */
+    memcpy(bitmap_copy, xface->bitmap, XFACE_PIXELS);
+    ff_xface_generate_face(xface->bitmap, bitmap_copy);
+
+    encode_block(xface->bitmap,                         16, 16, 0, &pq);
+    encode_block(xface->bitmap + 16,                    16, 16, 0, &pq);
+    encode_block(xface->bitmap + 32,                    16, 16, 0, &pq);
+    encode_block(xface->bitmap + XFACE_WIDTH * 16,      16, 16, 0, &pq);
+    encode_block(xface->bitmap + XFACE_WIDTH * 16 + 16, 16, 16, 0, &pq);
+    encode_block(xface->bitmap + XFACE_WIDTH * 16 + 32, 16, 16, 0, &pq);
+    encode_block(xface->bitmap + XFACE_WIDTH * 32,      16, 16, 0, &pq);
+    encode_block(xface->bitmap + XFACE_WIDTH * 32 + 16, 16, 16, 0, &pq);
+    encode_block(xface->bitmap + XFACE_WIDTH * 32 + 32, 16, 16, 0, &pq);
+
+    while (pq.prob_ranges_idx > 0)
+        push_integer(&b, pq.prob_ranges[--pq.prob_ranges_idx]);
+
+    /* write the inverted big integer in b to intbuf */
+    i = 0;
+    while (b.nb_words) {
+        uint8_t r;
+        ff_big_div(&b, XFACE_PRINTS, &r);
+        intbuf[i++] = r + XFACE_FIRST_PRINT;
+    }
+
+    if ((ret = ff_alloc_packet2(avctx, pkt, i+2)) < 0)
+        return ret;
+
+    /* revert the number, and close the buffer */
+    p = pkt->data;
+    while (--i >= 0)
+        *(p++) = intbuf[i];
+    *(p++) = '\n';
+    *(p++) = 0;
+
+    pkt->flags |= AV_PKT_FLAG_KEY;
+    *got_packet = 1;
+
+    return 0;
+}
+
+static av_cold int xface_encode_close(AVCodecContext *avctx)
+{
+    av_freep(&avctx->coded_frame);
+
+    return 0;
+}
+
+AVCodec ff_xface_encoder = {
+    .name           = "xface",
+    .type           = AVMEDIA_TYPE_VIDEO,
+    .id             = AV_CODEC_ID_XFACE,
+    .priv_data_size = sizeof(XFaceContext),
+    .init           = xface_encode_init,
+    .close          = xface_encode_close,
+    .encode2        = xface_encode_frame,
+    .pix_fmts       = (const enum PixelFormat[]) { AV_PIX_FMT_MONOWHITE, AV_PIX_FMT_NONE },
+    .long_name      = NULL_IF_CONFIG_SMALL("X-face image"),
+};