mirror of
https://git.videolan.org/git/ffmpeg.git
synced 2024-08-22 01:05:05 +02:00
230 lines
6.1 KiB
C
230 lines
6.1 KiB
C
/*
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* VBLE Decoder
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* Copyright (c) 2011 Derek Buitenhuis
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*
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* This file is part of Libav.
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*
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* Libav is free software; you can redistribute it and/or
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* modify it under the terms of the GNU Lesser General Public
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* License as published by the Free Software Foundation; either
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* version 2.1 of the License, or (at your option) any later version.
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*
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* Libav is distributed in the hope that it will be useful,
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* but WITHOUT ANY WARRANTY; without even the implied warranty of
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* MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
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* Lesser General Public License for more details.
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*
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* You should have received a copy of the GNU Lesser General Public
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* License along with Libav; if not, write to the Free Software
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* Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA
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*/
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/**
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* @file
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* VBLE Decoder
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*/
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#define BITSTREAM_READER_LE
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#include "avcodec.h"
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#include "dsputil.h"
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#include "get_bits.h"
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typedef struct {
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AVCodecContext *avctx;
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DSPContext dsp;
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int size;
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uint8_t *val; /* First holds the lengths of vlc symbols and then their values */
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} VBLEContext;
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static uint8_t vble_read_reverse_unary(GetBitContext *gb)
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{
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/* At most we need to read 9 bits total to get indices up to 8 */
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uint8_t val = show_bits(gb, 8);
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if (val) {
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val = 7 - av_log2_16bit(av_reverse[val]);
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skip_bits(gb, val + 1);
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return val;
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} else {
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skip_bits(gb, 8);
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if (get_bits1(gb))
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return 8;
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}
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/* Return something larger than 8 on error */
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return UINT8_MAX;
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}
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static int vble_unpack(VBLEContext *ctx, GetBitContext *gb)
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{
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int i;
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/* Read all the lengths in first */
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for (i = 0; i < ctx->size; i++) {
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ctx->val[i] = vble_read_reverse_unary(gb);
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if (ctx->val[i] == UINT8_MAX)
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return -1;
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}
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for (i = 0; i < ctx->size; i++) {
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/* Check we have enough bits left */
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if (get_bits_left(gb) < ctx->val[i])
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return -1;
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/* get_bits can't take a length of 0 */
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if (ctx->val[i])
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ctx->val[i] = (1 << ctx->val[i]) + get_bits(gb, ctx->val[i]) - 1;
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}
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return 0;
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}
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static void vble_restore_plane(VBLEContext *ctx, int plane, int offset,
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int width, int height)
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{
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AVFrame *pic = ctx->avctx->coded_frame;
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uint8_t *dst = pic->data[plane];
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uint8_t *val = ctx->val + offset;
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int stride = pic->linesize[plane];
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int i, j, left, left_top;
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for (i = 0; i < height; i++) {
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for (j = 0; j < width; j++)
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val[j] = (val[j] >> 1) ^ -(val[j] & 1);
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if (i) {
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left = 0;
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left_top = dst[-stride];
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ctx->dsp.add_hfyu_median_prediction(dst, dst-stride, val,
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width, &left, &left_top);
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} else {
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dst[0] = val[0];
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for (j = 1; j < width; j++)
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dst[j] = val[j] + dst[j - 1];
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}
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dst += stride;
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val += width;
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}
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}
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static int vble_decode_frame(AVCodecContext *avctx, void *data, int *data_size,
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AVPacket *avpkt)
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{
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VBLEContext *ctx = avctx->priv_data;
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AVFrame *pic = avctx->coded_frame;
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GetBitContext gb;
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const uint8_t *src = avpkt->data;
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int version;
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int offset = 0;
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int width_uv = avctx->width / 2, height_uv = avctx->height / 2;
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pic->reference = 0;
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/* Clear buffer if need be */
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if (pic->data[0])
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avctx->release_buffer(avctx, pic);
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/* Allocate buffer */
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if (avctx->get_buffer(avctx, pic) < 0) {
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av_log(avctx, AV_LOG_ERROR, "Could not allocate buffer.\n");
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return AVERROR(ENOMEM);
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}
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/* Set flags */
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pic->key_frame = 1;
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pic->pict_type = AV_PICTURE_TYPE_I;
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/* Version should always be 1 */
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version = AV_RL32(src);
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if (version != 1) {
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av_log(avctx, AV_LOG_ERROR, "Unsupported VBLE Version: %d\n", version);
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return AVERROR_INVALIDDATA;
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}
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init_get_bits(&gb, src + 4, (avpkt->size - 4) * 8);
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/* Unpack */
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if (vble_unpack(ctx, &gb) < 0) {
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av_log(avctx, AV_LOG_ERROR, "Invalid Code\n");
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return AVERROR_INVALIDDATA;
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}
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/* Restore planes. Should be almost identical to Huffyuv's. */
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vble_restore_plane(ctx, 0, offset, avctx->width, avctx->height);
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/* Chroma */
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if (!(ctx->avctx->flags & CODEC_FLAG_GRAY)) {
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offset += avctx->width * avctx->height;
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vble_restore_plane(ctx, 1, offset, width_uv, height_uv);
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offset += width_uv * height_uv;
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vble_restore_plane(ctx, 2, offset, width_uv, height_uv);
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}
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*data_size = sizeof(AVFrame);
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*(AVFrame *)data = *pic;
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return avpkt->size;
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}
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static av_cold int vble_decode_close(AVCodecContext *avctx)
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{
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VBLEContext *ctx = avctx->priv_data;
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AVFrame *pic = avctx->coded_frame;
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if (pic->data[0])
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avctx->release_buffer(avctx, pic);
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av_freep(&avctx->coded_frame);
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av_freep(&ctx->val);
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return 0;
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}
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static av_cold int vble_decode_init(AVCodecContext *avctx)
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{
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VBLEContext *ctx = avctx->priv_data;
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/* Stash for later use */
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ctx->avctx = avctx;
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dsputil_init(&ctx->dsp, avctx);
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avctx->pix_fmt = PIX_FMT_YUV420P;
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avctx->bits_per_raw_sample = 8;
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avctx->coded_frame = avcodec_alloc_frame();
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if (!avctx->coded_frame) {
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av_log(avctx, AV_LOG_ERROR, "Could not allocate frame.\n");
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return AVERROR(ENOMEM);
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}
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ctx->size = avpicture_get_size(avctx->pix_fmt,
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avctx->width, avctx->height);
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ctx->val = av_malloc(ctx->size * sizeof(*ctx->val));
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if (!ctx->val) {
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av_log(avctx, AV_LOG_ERROR, "Could not allocate values buffer.\n");
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vble_decode_close(avctx);
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return AVERROR(ENOMEM);
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}
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return 0;
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}
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AVCodec ff_vble_decoder = {
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.name = "vble",
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.type = AVMEDIA_TYPE_VIDEO,
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.id = CODEC_ID_VBLE,
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.priv_data_size = sizeof(VBLEContext),
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.init = vble_decode_init,
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.close = vble_decode_close,
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.decode = vble_decode_frame,
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.capabilities = CODEC_CAP_DR1,
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.long_name = NULL_IF_CONFIG_SMALL("VBLE Lossless Codec"),
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};
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