[FFmpeg-devel] [PATCH] avcodec: add ARBC decoder
James Almer
jamrial at gmail.com
Tue Jan 22 15:22:29 EET 2019
On 1/22/2019 6:55 AM, Paul B Mahol wrote:
> Thanks Kostya for great help in reversing binary.
>
> Signed-off-by: Paul B Mahol <onemda at gmail.com>
> ---
> libavcodec/Makefile | 1 +
> libavcodec/allcodecs.c | 1 +
> libavcodec/arbc.c | 203 ++++++++++++++++++++++++++++++++++++++++
> libavcodec/avcodec.h | 1 +
> libavcodec/codec_desc.c | 7 ++
> libavformat/riff.c | 1 +
> 6 files changed, 214 insertions(+)
> create mode 100644 libavcodec/arbc.c
>
> diff --git a/libavcodec/Makefile b/libavcodec/Makefile
> index bf746c143d..8e240aecf0 100644
> --- a/libavcodec/Makefile
> +++ b/libavcodec/Makefile
> @@ -198,6 +198,7 @@ OBJS-$(CONFIG_APTX_HD_DECODER) += aptx.o
> OBJS-$(CONFIG_APTX_HD_ENCODER) += aptx.o
> OBJS-$(CONFIG_APNG_DECODER) += png.o pngdec.o pngdsp.o
> OBJS-$(CONFIG_APNG_ENCODER) += png.o pngenc.o
> +OBJS-$(CONFIG_ARBC_DECODER) += arbc.o
> OBJS-$(CONFIG_SSA_DECODER) += assdec.o ass.o
> OBJS-$(CONFIG_SSA_ENCODER) += assenc.o ass.o
> OBJS-$(CONFIG_ASS_DECODER) += assdec.o ass.o
> diff --git a/libavcodec/allcodecs.c b/libavcodec/allcodecs.c
> index fe0376e27e..5cbb09a5a4 100644
> --- a/libavcodec/allcodecs.c
> +++ b/libavcodec/allcodecs.c
> @@ -41,6 +41,7 @@ extern AVCodec ff_anm_decoder;
> extern AVCodec ff_ansi_decoder;
> extern AVCodec ff_apng_encoder;
> extern AVCodec ff_apng_decoder;
> +extern AVCodec ff_arbc_decoder;
> extern AVCodec ff_asv1_encoder;
> extern AVCodec ff_asv1_decoder;
> extern AVCodec ff_asv2_encoder;
> diff --git a/libavcodec/arbc.c b/libavcodec/arbc.c
> new file mode 100644
> index 0000000000..59a1d7bf0a
> --- /dev/null
> +++ b/libavcodec/arbc.c
> @@ -0,0 +1,203 @@
> +/*
> + * Gryphon's Anim Compressor decoder
> + * Copyright (c) 2018 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 <stdio.h>
> +#include <stdlib.h>
> +#include <string.h>
> +
> +#include "libavutil/imgutils.h"
> +#include "libavutil/internal.h"
> +#include "libavutil/intreadwrite.h"
> +#include "libavutil/mem.h"
> +
> +#include "avcodec.h"
> +#include "bytestream.h"
> +#include "internal.h"
> +
> +typedef struct ARBCContext {
> + GetByteContext gb;
> +
> + AVFrame *prev_frame;
> +} ARBCContext;
> +
> +static void fill_tile4(AVCodecContext *avctx, uint8_t *color, AVFrame *frame)
> +{
> + ARBCContext *s = avctx->priv_data;
> + GetByteContext *gb = &s->gb;
> + int nb_tiles = bytestream2_get_le16(gb);
> + int h = avctx->height - 1;
> +
> + for (int i = 0; i < nb_tiles; i++) {
> + int y = bytestream2_get_byte(gb);
> + int x = bytestream2_get_byte(gb);
> + uint16_t mask = bytestream2_get_le16(gb);
> + int start_y = y * 4, start_x = x * 4;
> + int end_y = start_y + 4, end_x = start_x + 4;
> +
> + for (int j = start_y; j < end_y; j++) {
> + for (int k = start_x; k < end_x; k++) {
> + if (mask & 0x8000) {
> + if (j >= avctx->height || k >= avctx->width)
> + continue;
> + frame->data[0][frame->linesize[0] * (h - j) + 3 * k + 0] = color[0];
> + frame->data[0][frame->linesize[0] * (h - j) + 3 * k + 1] = color[1];
> + frame->data[0][frame->linesize[0] * (h - j) + 3 * k + 2] = color[2];
> + }
> + mask = mask << 1;
get_bits(). Same below.
> + }
> + }
> + }
> +}
> +
> +static void fill_tileX(AVCodecContext *avctx, int tile_width, int tile_height,
> + uint8_t *color, AVFrame *frame)
> +{
> + ARBCContext *s = avctx->priv_data;
> + GetByteContext *gb = &s->gb;
> + const int step_h = tile_height / 4;
> + const int step_w = tile_width / 4;
> + int nb_tiles = bytestream2_get_le16(gb);
> + int h = avctx->height - 1;
> +
> + for (int i = 0; i < nb_tiles; i++) {
> + int y = bytestream2_get_byte(gb);
> + int x = bytestream2_get_byte(gb);
> + uint16_t mask = bytestream2_get_le16(gb);
> + int start_y = y * tile_height, start_x = x * tile_width;
> + int end_y = start_y + tile_height, end_x = start_x + tile_width;
> +
> + for (int j = start_y; j < end_y; j += step_h) {
> + for (int k = start_x; k < end_x; k += step_w) {
> + if (mask & 0x8000U) {
> + for (int m = 0; m < step_h; m++) {
> + for (int n = 0; n < step_w; n++) {
> + if (j + m >= avctx->height || k + n >= avctx->width)
> + continue;
> + frame->data[0][frame->linesize[0] * (h - (j + m)) + 3 * (k + n) + 0] = color[0];
> + frame->data[0][frame->linesize[0] * (h - (j + m)) + 3 * (k + n) + 1] = color[1];
> + frame->data[0][frame->linesize[0] * (h - (j + m)) + 3 * (k + n) + 2] = color[2];
> + }
> + }
> + }
> + mask = mask << 1;
> + }
> + }
> + }
> +}
> +
> +static int decode_frame(AVCodecContext *avctx, void *data,
> + int *got_frame, AVPacket *avpkt)
> +{
> + ARBCContext *s = avctx->priv_data;
> + AVFrame *const frame = data;
No const.
> + int ret, nb_segments, keyframe = 1;
> +
> + if (avpkt->size < 1)
> + return AVERROR_INVALIDDATA;
> +
> + if ((ret = ff_get_buffer(avctx, frame, AV_GET_BUFFER_FLAG_REF)) < 0)
> + return ret;
> +
> + if (s->prev_frame->data[0]) {
> + ret = av_frame_copy(frame, s->prev_frame);
> + if (ret < 0)
> + return ret;
> + }
> +
> + bytestream2_init(&s->gb, avpkt->data, avpkt->size);
> + bytestream2_skip(&s->gb, 8);
> + nb_segments = bytestream2_get_le16(&s->gb);
> + if (nb_segments == 0)
> + keyframe = 0;
> +
> + for (int i = 0; i < nb_segments; i++) {
> + int resolution_flag;
> + uint8_t fill[3];
> +
> + if (bytestream2_get_bytes_left(&s->gb) <= 0)
> + return AVERROR_INVALIDDATA;
> +
> + fill[0] = bytestream2_get_byte(&s->gb);
> + bytestream2_skip(&s->gb, 1);
> + fill[1] = bytestream2_get_byte(&s->gb);
> + bytestream2_skip(&s->gb, 1);
> + fill[2] = bytestream2_get_byte(&s->gb);
> + bytestream2_skip(&s->gb, 1);
> + resolution_flag = bytestream2_get_byte(&s->gb);
> +
> + if (resolution_flag & 0x10)
> + fill_tileX(avctx, 1024, 1024, fill, frame);
> + if (resolution_flag & 0x08)
> + fill_tileX(avctx, 256, 256, fill, frame);
> + if (resolution_flag & 0x04)
> + fill_tileX(avctx, 64, 64, fill, frame);
> + if (resolution_flag & 0x02)
> + fill_tileX(avctx, 16, 16, fill, frame);
> + if (resolution_flag & 0x01)
> + fill_tile4(avctx, fill, frame);
> + }
> +
> + av_frame_unref(s->prev_frame);
> + if ((ret = av_frame_ref(s->prev_frame, frame)) < 0)
> + return ret;
> +
> + frame->pict_type = keyframe ? AV_PICTURE_TYPE_I : AV_PICTURE_TYPE_P;
> + frame->key_frame = keyframe;
> + *got_frame = 1;
> +
> + return avpkt->size;
> +}
> +
> +static av_cold int decode_init(AVCodecContext *avctx)
> +{
> + ARBCContext *s = avctx->priv_data;
> +
> + avctx->pix_fmt = AV_PIX_FMT_RGB24;
> +
> + s->prev_frame = av_frame_alloc();
> + if (!s->prev_frame)
> + return AVERROR(ENOMEM);
> +
> + return 0;
> +}
> +
> +static av_cold int decode_close(AVCodecContext *avctx)
> +{
> + ARBCContext *s = avctx->priv_data;
> +
> + av_frame_free(&s->prev_frame);
> +
> + return 0;
> +}
> +
> +AVCodec ff_arbc_decoder = {
> + .name = "arbc",
> + .long_name = NULL_IF_CONFIG_SMALL("Gryphon's Anim Compressor"),
> + .type = AVMEDIA_TYPE_VIDEO,
> + .id = AV_CODEC_ID_ARBC,
> + .priv_data_size = sizeof(ARBCContext),
> + .init = decode_init,
> + .decode = decode_frame,
> + .close = decode_close,
> + .capabilities = AV_CODEC_CAP_DR1,
> + .caps_internal = FF_CODEC_CAP_INIT_THREADSAFE |
> + FF_CODEC_CAP_INIT_CLEANUP,
No need for this one. Only s->prev_frame is allocated in init(), and if
that fails then close() would do nothing.
What's missing is AV_CODEC_CAP_DR1 seeing you use get_buffer.
> +};
> diff --git a/libavcodec/avcodec.h b/libavcodec/avcodec.h
> index 90f9f08289..72dc277dfd 100644
> --- a/libavcodec/avcodec.h
> +++ b/libavcodec/avcodec.h
> @@ -453,6 +453,7 @@ enum AVCodecID {
> AV_CODEC_ID_WCMV,
> AV_CODEC_ID_RASC,
> AV_CODEC_ID_HYMT,
> + AV_CODEC_ID_ARBC,
>
> /* various PCM "codecs" */
> AV_CODEC_ID_FIRST_AUDIO = 0x10000, ///< A dummy id pointing at the start of audio codecs
> diff --git a/libavcodec/codec_desc.c b/libavcodec/codec_desc.c
> index 10a639101c..7b254c1d45 100644
> --- a/libavcodec/codec_desc.c
> +++ b/libavcodec/codec_desc.c
> @@ -1698,6 +1698,13 @@ static const AVCodecDescriptor codec_descriptors[] = {
> .long_name = NULL_IF_CONFIG_SMALL("HuffYUV MT"),
> .props = AV_CODEC_PROP_INTRA_ONLY | AV_CODEC_PROP_LOSSLESS,
> },
> + {
> + .id = AV_CODEC_ID_ARBC,
> + .type = AVMEDIA_TYPE_VIDEO,
> + .name = "arbc",
> + .long_name = NULL_IF_CONFIG_SMALL("Gryphon's Anim Compressor"),
> + .props = AV_CODEC_PROP_LOSSY,
> + },
>
> /* various PCM "codecs" */
> {
> diff --git a/libavformat/riff.c b/libavformat/riff.c
> index d5a509c8b9..8f0fd99e22 100644
> --- a/libavformat/riff.c
> +++ b/libavformat/riff.c
> @@ -476,6 +476,7 @@ const AVCodecTag ff_codec_bmp_tags[] = {
> { AV_CODEC_ID_WCMV, MKTAG('W', 'C', 'M', 'V') },
> { AV_CODEC_ID_RASC, MKTAG('R', 'A', 'S', 'C') },
> { AV_CODEC_ID_HYMT, MKTAG('H', 'Y', 'M', 'T') },
> + { AV_CODEC_ID_ARBC, MKTAG('A', 'R', 'B', 'C') },
> { AV_CODEC_ID_NONE, 0 }
> };
>
>
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