[FFmpeg-devel] [PATCH 2/3] avcodec: add SGA Video decoder
Paul B Mahol
onemda at gmail.com
Fri Feb 26 13:29:18 EET 2021
Signed-off-by: Paul B Mahol <onemda at gmail.com>
---
libavcodec/Makefile | 1 +
libavcodec/allcodecs.c | 1 +
libavcodec/codec_desc.c | 7 +
libavcodec/codec_id.h | 1 +
libavcodec/sga.c | 534 ++++++++++++++++++++++++++++++++++++++++
5 files changed, 544 insertions(+)
create mode 100644 libavcodec/sga.c
diff --git a/libavcodec/Makefile b/libavcodec/Makefile
index fe7026c1db..850657ae3c 100644
--- a/libavcodec/Makefile
+++ b/libavcodec/Makefile
@@ -609,6 +609,7 @@ OBJS-$(CONFIG_SANM_DECODER) += sanm.o
OBJS-$(CONFIG_SCPR_DECODER) += scpr.o
OBJS-$(CONFIG_SCREENPRESSO_DECODER) += screenpresso.o
OBJS-$(CONFIG_SDX2_DPCM_DECODER) += dpcm.o
+OBJS-$(CONFIG_SGA_DECODER) += sga.o
OBJS-$(CONFIG_SGI_DECODER) += sgidec.o
OBJS-$(CONFIG_SGI_ENCODER) += sgienc.o rle.o
OBJS-$(CONFIG_SGIRLE_DECODER) += sgirledec.o
diff --git a/libavcodec/allcodecs.c b/libavcodec/allcodecs.c
index 990998b64b..a04faead16 100644
--- a/libavcodec/allcodecs.c
+++ b/libavcodec/allcodecs.c
@@ -289,6 +289,7 @@ extern AVCodec ff_s302m_decoder;
extern AVCodec ff_sanm_decoder;
extern AVCodec ff_scpr_decoder;
extern AVCodec ff_screenpresso_decoder;
+extern AVCodec ff_sga_decoder;
extern AVCodec ff_sgi_encoder;
extern AVCodec ff_sgi_decoder;
extern AVCodec ff_sgirle_decoder;
diff --git a/libavcodec/codec_desc.c b/libavcodec/codec_desc.c
index f64ba488f2..17f8a14044 100644
--- a/libavcodec/codec_desc.c
+++ b/libavcodec/codec_desc.c
@@ -1849,6 +1849,13 @@ static const AVCodecDescriptor codec_descriptors[] = {
.long_name = NULL_IF_CONFIG_SMALL("Simbiosis Interactive IMX Video"),
.props = AV_CODEC_PROP_LOSSY,
},
+ {
+ .id = AV_CODEC_ID_SGA_VIDEO,
+ .type = AVMEDIA_TYPE_VIDEO,
+ .name = "sga",
+ .long_name = NULL_IF_CONFIG_SMALL("Digital Pictures SGA Video"),
+ .props = AV_CODEC_PROP_LOSSY,
+ },
/* various PCM "codecs" */
{
diff --git a/libavcodec/codec_id.h b/libavcodec/codec_id.h
index 7dd316afd2..ab7bc68ee2 100644
--- a/libavcodec/codec_id.h
+++ b/libavcodec/codec_id.h
@@ -306,6 +306,7 @@ enum AVCodecID {
AV_CODEC_ID_ARGO,
AV_CODEC_ID_CRI,
AV_CODEC_ID_SIMBIOSIS_IMX,
+ AV_CODEC_ID_SGA_VIDEO,
/* various PCM "codecs" */
AV_CODEC_ID_FIRST_AUDIO = 0x10000, ///< A dummy id pointing at the start of audio codecs
diff --git a/libavcodec/sga.c b/libavcodec/sga.c
new file mode 100644
index 0000000000..00752a5843
--- /dev/null
+++ b/libavcodec/sga.c
@@ -0,0 +1,534 @@
+/*
+ * Copyright (c) 2021 Paul B Mahol
+ *
+ * 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/avassert.h"
+#include "libavutil/common.h"
+#include "avcodec.h"
+#include "get_bits.h"
+#include "bytestream.h"
+#include "internal.h"
+
+#define PALDATA_FOLLOWS_TILEDATA 4
+#define HAVE_COMPRESSED_TILEMAP 32
+#define HAVE_TILEMAP 128
+
+typedef struct SGAVideoContext {
+ GetByteContext gb;
+
+ int metadata_size;
+ int tiledata_size;
+ int tiledata_offset;
+ int tilemapdata_size;
+ int tilemapdata_offset;
+ int paldata_size;
+ int paldata_offset;
+ int palmapdata_offset;
+ int palmapdata_size;
+
+ int flags;
+ int nb_pal;
+ int nb_tiles;
+ int tiles_w, tiles_h;
+ int shift;
+ int plus;
+ int swap;
+
+ uint32_t pal[256];
+ uint8_t *tileindex_data;
+ unsigned tileindex_size;
+ uint8_t *palmapindex_data;
+ unsigned palmapindex_size;
+ uint8_t uncompressed[65536];
+} SGAVideoContext;
+
+static av_cold int sga_decode_init(AVCodecContext *avctx)
+{
+ avctx->pix_fmt = AV_PIX_FMT_PAL8;
+ return 0;
+}
+
+static int decode_palette(GetByteContext *gb, uint32_t *pal)
+{
+ GetBitContext gbit;
+
+ if (bytestream2_get_bytes_left(gb) < 18)
+ return AVERROR_INVALIDDATA;
+
+ memset(pal, 0, 16 * sizeof(*pal));
+ init_get_bits8(&gbit, gb->buffer, 18);
+
+ for (int RGBIndex = 0; RGBIndex < 3; RGBIndex++) {
+ for (int index = 0; index < 16; index++) {
+ unsigned color = get_bits1(&gbit) << RGBIndex;
+ pal[15 - index] |= color << (5 + 16);
+ }
+ }
+
+ for (int RGBIndex = 0; RGBIndex < 3; RGBIndex++) {
+ for (int index = 0; index < 16; index++) {
+ unsigned color = get_bits1(&gbit) << RGBIndex;
+ pal[15 - index] |= color << (5 + 8);
+ }
+ }
+
+ for (int RGBIndex = 0; RGBIndex < 3; RGBIndex++) {
+ for (int index = 0; index < 16; index++) {
+ unsigned color = get_bits1(&gbit) << RGBIndex;
+ pal[15 - index] |= color << (5 + 0);
+ }
+ }
+
+ for (int index = 0; index < 16; index++)
+ pal[index] = (0xFFU << 24) | pal[index] | (pal[index] >> 3);
+
+ bytestream2_skip(gb, 18);
+
+ return 0;
+}
+
+static int decode_index_palmap(SGAVideoContext *s, AVFrame *frame)
+{
+ const uint8_t *tt = s->tileindex_data;
+
+ for (int y = 0; y < s->tiles_h; y++) {
+ for (int x = 0; x < s->tiles_w; x++) {
+ int pal_idx = s->palmapindex_data[y * s->tiles_w + x] * 16;
+ uint8_t *dst = frame->data[0] + y * 8 * frame->linesize[0] + x * 8;
+
+ for (int yy = 0; yy < 8; yy++) {
+ for (int xx = 0; xx < 8; xx++)
+ dst[xx] = pal_idx + tt[xx];
+ tt += 8;
+
+ dst += frame->linesize[0];
+ }
+ }
+ }
+
+ return 0;
+}
+
+static int decode_index_tilemap(SGAVideoContext *s, AVFrame *frame)
+{
+ GetByteContext *gb = &s->gb;
+ GetBitContext pm;
+
+ bytestream2_seek(gb, s->tilemapdata_offset, SEEK_SET);
+ if (bytestream2_get_bytes_left(gb) < s->tilemapdata_size)
+ return AVERROR_INVALIDDATA;
+
+ init_get_bits8(&pm, gb->buffer, s->tilemapdata_size);
+
+ for (int y = 0; y < s->tiles_h; y++) {
+ for (int x = 0; x < s->tiles_w; x++) {
+ uint8_t tile[64];
+ int tilemap = get_bits(&pm, 16);
+ int flip_x = (tilemap >> 11) & 1;
+ int flip_y = (tilemap >> 12) & 1;
+ int tindex = av_clip((tilemap & 511) - 1, 0, s->nb_tiles - 1);
+ const uint8_t *tt = s->tileindex_data + tindex * 64;
+ int pal_idx = ((tilemap >> 13) & 3) * 16;
+ uint8_t *dst = frame->data[0] + y * 8 * frame->linesize[0] + x * 8;
+
+ if (!flip_x && !flip_y) {
+ memcpy(tile, tt, 64);
+ } else if (flip_x && flip_y) {
+ for (int i = 0; i < 8; i++) {
+ for (int j = 0; j < 8; j++)
+ tile[i * 8 + j] = tt[(7 - i) * 8 + 7 - j];
+ }
+ } else if (flip_x) {
+ for (int i = 0; i < 8; i++) {
+ for (int j = 0; j < 8; j++)
+ tile[i * 8 + j] = tt[i * 8 + 7 - j];
+ }
+ } else {
+ for (int i = 0; i < 8; i++) {
+ for (int j = 0; j < 8; j++)
+ tile[i * 8 + j] = tt[(7 - i) * 8 + j];
+ }
+ }
+
+ for (int yy = 0; yy < 8; yy++) {
+ for (int xx = 0; xx < 8; xx++)
+ dst[xx] = pal_idx + tile[xx + yy * 8];
+
+ dst += frame->linesize[0];
+ }
+ }
+ }
+
+ return 0;
+}
+
+static int decode_index(SGAVideoContext *s, AVFrame *frame)
+{
+ const uint8_t *src = s->tileindex_data;
+ uint8_t *dst = frame->data[0];
+
+ for (int y = 0; y < frame->height; y += 8) {
+ for (int x = 0; x < frame->width; x += 8) {
+ for (int yy = 0; yy < 8; yy++) {
+ for (int xx = 0; xx < 8; xx++)
+ dst[x + xx + yy * frame->linesize[0]] = src[xx];
+ src += 8;
+ }
+ }
+
+ dst += 8 * frame->linesize[0];
+ }
+
+ return 0;
+}
+
+static int lzss_decompress(AVCodecContext *avctx,
+ GetByteContext *gb, uint8_t *dst,
+ int dst_size, int shift, int plus)
+{
+ int oi = 0;
+
+ while (bytestream2_get_bytes_left(gb) > 0 && oi < dst_size) {
+ uint16_t displace, header = bytestream2_get_be16(gb);
+ int count, offset;
+
+ for (int i = 0; i < 16; i++) {
+ switch (header >> 15) {
+ case 0:
+ if (oi + 2 < dst_size) {
+ dst[oi++] = bytestream2_get_byte(gb);
+ dst[oi++] = bytestream2_get_byte(gb);
+ }
+ break;
+ case 1:
+ displace = bytestream2_get_be16(gb);
+ count = displace >> shift;
+ offset = displace & ((1 << shift) - 1);
+
+ if (displace == 0) {
+ while (bytestream2_get_bytes_left(gb) > 0 &&
+ oi < dst_size)
+ dst[oi++] = bytestream2_get_byte(gb);
+ return oi;
+ }
+
+ count += plus;
+
+ if (offset <= 0)
+ offset = 1;
+ if (oi < offset)
+ return AVERROR_INVALIDDATA;
+ for (int j = 0; j < count * 2; j++) {
+ dst[oi] = dst[oi - offset];
+ oi++;
+ }
+ break;
+ }
+
+ header <<= 1;
+ }
+ }
+
+ return AVERROR_INVALIDDATA;
+}
+
+static int decode_palmapdata(AVCodecContext *avctx)
+{
+ SGAVideoContext *s = avctx->priv_data;
+ const int bits = (s->nb_pal + 1) / 2;
+ GetByteContext *gb = &s->gb;
+ GetBitContext pm;
+
+ bytestream2_seek(gb, s->palmapdata_offset, SEEK_SET);
+ if (bytestream2_get_bytes_left(gb) < s->palmapdata_size)
+ return AVERROR_INVALIDDATA;
+ init_get_bits8(&pm, gb->buffer, s->palmapdata_size);
+
+ for (int y = 0; y < s->tiles_h; y++) {
+ uint8_t *dst = s->palmapindex_data + y * s->tiles_w;
+
+ for (int x = 0; x < s->tiles_w; x++)
+ dst[x] = get_bits(&pm, bits);
+
+ dst += s->tiles_w;
+ }
+
+ return 0;
+}
+
+static int decode_tiledata(AVCodecContext *avctx)
+{
+ SGAVideoContext *s = avctx->priv_data;
+ GetByteContext *gb = &s->gb;
+ GetBitContext tm;
+
+ bytestream2_seek(gb, s->tiledata_offset, SEEK_SET);
+ if (bytestream2_get_bytes_left(gb) < s->tiledata_size)
+ return AVERROR_INVALIDDATA;
+ init_get_bits8(&tm, gb->buffer, s->tiledata_size);
+
+ for (int n = 0; n < s->nb_tiles; n++) {
+ uint8_t *dst = s->tileindex_data + n * 64;
+
+ for (int yy = 0; yy < 8; yy++) {
+ for (int xx = 0; xx < 8; xx++)
+ dst[xx] = get_bits(&tm, 4);
+
+ dst += 8;
+ }
+ }
+
+ for (int i = 0; i < s->nb_tiles && s->swap; i++) {
+ uint8_t *dst = s->tileindex_data + i * 64;
+
+ for (int j = 8; j < 64; j += 16) {
+ for (int k = 0; k < 8; k += 2)
+ FFSWAP(uint8_t, dst[j + k], dst[j+k+1]);
+ }
+ }
+
+ return 0;
+}
+
+static int sga_decode_frame(AVCodecContext *avctx, void *data,
+ int *got_frame, AVPacket *avpkt)
+{
+ SGAVideoContext *s = avctx->priv_data;
+ GetByteContext *gb = &s->gb;
+ AVFrame *frame = data;
+ int ret, type;
+
+ if (avpkt->size <= 14)
+ return AVERROR_INVALIDDATA;
+
+ s->flags = avpkt->data[8];
+ s->nb_pal = avpkt->data[9];
+ s->tiles_w = avpkt->data[10];
+ s->tiles_h = avpkt->data[11];
+
+ if (s->nb_pal > 4)
+ return AVERROR_INVALIDDATA;
+
+ if ((ret = ff_set_dimensions(avctx,
+ s->tiles_w * 8,
+ s->tiles_h * 8)) < 0)
+ return ret;
+
+ av_fast_padded_malloc(&s->tileindex_data, &s->tileindex_size,
+ avctx->width * avctx->height);
+ if (!s->tileindex_data)
+ return AVERROR(ENOMEM);
+
+ av_fast_padded_malloc(&s->palmapindex_data, &s->palmapindex_size,
+ s->tiles_w * s->tiles_h);
+ if (!s->palmapindex_data)
+ return AVERROR(ENOMEM);
+
+ if ((ret = ff_get_buffer(avctx, frame, 0)) < 0)
+ return ret;
+
+ bytestream2_init(gb, avpkt->data, avpkt->size);
+
+ type = bytestream2_get_byte(gb);
+ s->metadata_size = 12 + ((!!(s->flags & HAVE_TILEMAP)) * 2);
+ s->nb_tiles = s->flags & HAVE_TILEMAP ? AV_RB16(avpkt->data + 12) : s->tiles_w * s->tiles_h;
+ if (s->nb_tiles > s->tiles_w * s->tiles_h)
+ return AVERROR_INVALIDDATA;
+
+ av_log(avctx, AV_LOG_DEBUG, "type: %X flags: %X nb_tiles: %d\n", type, s->flags, s->nb_tiles);
+
+ switch (type) {
+ case 0xE7:
+ case 0xCB:
+ case 0xCD:
+ s->swap = 1;
+ s->shift = 12;
+ s->plus = 1;
+ break;
+ case 0xC9:
+ s->swap = 1;
+ s->shift = 13;
+ s->plus = 1;
+ break;
+ case 0xC8:
+ s->swap = 1;
+ s->shift = 13;
+ s->plus = 0;
+ break;
+ case 0xC7:
+ s->swap = 0;
+ s->shift = 13;
+ s->plus = 1;
+ break;
+ case 0xC6:
+ s->swap = 0;
+ s->shift = 13;
+ s->plus = 0;
+ break;
+ }
+
+ if (type == 0xE7) {
+ int offset = s->metadata_size, left;
+ int sizes[3];
+
+ bytestream2_seek(gb, s->metadata_size, SEEK_SET);
+
+ for (int i = 0; i < 3; i++)
+ sizes[i] = bytestream2_get_be16(gb);
+
+ for (int i = 0; i < 3; i++) {
+ int size = sizes[i];
+ int raw = size >> 15;
+
+ size &= (1 << 15) - 1;
+
+ if (raw) {
+ if (bytestream2_get_bytes_left(gb) < size)
+ return AVERROR_INVALIDDATA;
+
+ if (sizeof(s->uncompressed) - offset < size)
+ return AVERROR_INVALIDDATA;
+
+ memcpy(s->uncompressed + offset, gb->buffer, size);
+ bytestream2_skip(gb, size);
+ } else {
+ GetByteContext gb2;
+
+ if (bytestream2_get_bytes_left(gb) < size)
+ return AVERROR_INVALIDDATA;
+
+ bytestream2_init(&gb2, gb->buffer, size);
+ ret = lzss_decompress(avctx, &gb2, s->uncompressed + offset,
+ sizeof(s->uncompressed) - offset, s->shift, s->plus);
+ if (ret < 0)
+ return ret;
+ bytestream2_skip(gb, size);
+ size = ret;
+ }
+
+ offset += size;
+ }
+
+ left = bytestream2_get_bytes_left(gb);
+ if (sizeof(s->uncompressed) - offset < left)
+ return AVERROR_INVALIDDATA;
+
+ bytestream2_get_buffer(gb, s->uncompressed + offset, left);
+
+ offset += left;
+ bytestream2_init(gb, s->uncompressed, offset);
+ }
+
+ switch (type) {
+ case 0xCD:
+ case 0xCB:
+ case 0xC9:
+ case 0xC8:
+ case 0xC7:
+ case 0xC6:
+ bytestream2_seek(gb, s->metadata_size, SEEK_SET);
+ ret = lzss_decompress(avctx, gb, s->uncompressed + s->metadata_size,
+ sizeof(s->uncompressed) - s->metadata_size, s->shift, s->plus);
+ if (ret < 0)
+ return ret;
+ bytestream2_init(gb, s->uncompressed, ret + s->metadata_size);
+ case 0xE7:
+ case 0xC1:
+ s->tiledata_size = s->nb_tiles * 32;
+ s->paldata_size = s->nb_pal * 18;
+ s->tiledata_offset = s->flags & PALDATA_FOLLOWS_TILEDATA ? s->metadata_size : s->metadata_size + s->paldata_size;
+ s->paldata_offset = s->flags & PALDATA_FOLLOWS_TILEDATA ? s->metadata_size + s->tiledata_size : s->metadata_size;
+ s->palmapdata_offset = (s->flags & HAVE_TILEMAP) ? -1 : s->paldata_offset + s->paldata_size;
+ s->palmapdata_size = (s->flags & HAVE_TILEMAP) || s->nb_pal < 2 ? 0 : (s->tiles_w * s->tiles_h * ((s->nb_pal + 1) / 2) + 7) / 8;
+ s->tilemapdata_size = (s->flags & HAVE_TILEMAP) ? s->tiles_w * s->tiles_h * 2 : 0;
+ s->tilemapdata_offset = (s->flags & HAVE_TILEMAP) ? s->paldata_offset + s->paldata_size: -1;
+
+ bytestream2_seek(gb, s->paldata_offset, SEEK_SET);
+ for (int n = 0; n < s->nb_pal; n++) {
+ ret = decode_palette(gb, s->pal + 16 * n);
+ if (ret < 0)
+ return ret;
+ }
+
+ if (s->tiledata_size > 0) {
+ ret = decode_tiledata(avctx);
+ if (ret < 0)
+ return ret;
+ }
+
+ if (s->palmapdata_size > 0) {
+ ret = decode_palmapdata(avctx);
+ if (ret < 0)
+ return ret;
+ }
+
+ if (s->palmapdata_size > 0 && s->tiledata_size > 0) {
+ ret = decode_index_palmap(s, frame);
+ if (ret < 0)
+ return ret;
+ } else if (s->tilemapdata_size > 0 && s->tiledata_size > 0) {
+ ret = decode_index_tilemap(s, frame);
+ if (ret < 0)
+ return ret;
+ } else if (s->tiledata_size > 0) {
+ ret = decode_index(s, frame);
+ if (ret < 0)
+ return ret;
+ }
+ break;
+ default:
+ av_log(avctx, AV_LOG_ERROR, "Unknown type: %X\n", type);
+ return AVERROR_INVALIDDATA;
+ }
+
+ memcpy(frame->data[1], s->pal, AVPALETTE_SIZE);
+ frame->palette_has_changed = 1;
+ frame->pict_type = AV_PICTURE_TYPE_I;
+ frame->key_frame = 1;
+
+ *got_frame = 1;
+
+ return avpkt->size;
+}
+
+static av_cold int sga_decode_end(AVCodecContext *avctx)
+{
+ SGAVideoContext *s = avctx->priv_data;
+
+ av_freep(&s->tileindex_data);
+ s->tileindex_size = 0;
+
+ av_freep(&s->palmapindex_data);
+ s->palmapindex_size = 0;
+
+ return 0;
+}
+
+AVCodec ff_sga_decoder = {
+ .name = "sga",
+ .long_name = NULL_IF_CONFIG_SMALL("Digital Pictures SGA Video"),
+ .type = AVMEDIA_TYPE_VIDEO,
+ .id = AV_CODEC_ID_SGA_VIDEO,
+ .priv_data_size = sizeof(SGAVideoContext),
+ .init = sga_decode_init,
+ .decode = sga_decode_frame,
+ .close = sga_decode_end,
+ .capabilities = AV_CODEC_CAP_DR1,
+ .caps_internal = FF_CODEC_CAP_INIT_THREADSAFE,
+};
--
2.17.1
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