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This is possible, because every given FFCodec has to implement exactly one of these. Doing so decreases sizeof(FFCodec) and therefore decreases the size of the binary. Notice that in case of position-independent code the decrease is in .data.rel.ro, so that this translates to decreased memory consumption. Signed-off-by: Andreas Rheinhardt <andreas.rheinhardt@outlook.com>
109 lines
3.3 KiB
C
109 lines
3.3 KiB
C
/*
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* Aura 2 decoder
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*
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* This file is part of FFmpeg.
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*
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* FFmpeg 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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* FFmpeg 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 FFmpeg; 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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* Aura 2 decoder
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*/
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#include "avcodec.h"
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#include "codec_internal.h"
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#include "internal.h"
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#include "libavutil/internal.h"
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static av_cold int aura_decode_init(AVCodecContext *avctx)
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{
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/* width needs to be divisible by 4 for this codec to work */
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if (avctx->width & 0x3)
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return AVERROR(EINVAL);
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avctx->pix_fmt = AV_PIX_FMT_YUV422P;
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return 0;
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}
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static int aura_decode_frame(AVCodecContext *avctx, AVFrame *frame,
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int *got_frame, AVPacket *pkt)
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{
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uint8_t *Y, *U, *V;
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uint8_t val;
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int x, y, ret;
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const uint8_t *buf = pkt->data;
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/* prediction error tables (make it clear that they are signed values) */
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const int8_t *delta_table = (const int8_t*)buf + 16;
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if (pkt->size != 48 + avctx->height * avctx->width) {
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av_log(avctx, AV_LOG_ERROR, "got a buffer with %d bytes when %d were expected\n",
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pkt->size, 48 + avctx->height * avctx->width);
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return AVERROR_INVALIDDATA;
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}
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/* pixel data starts 48 bytes in, after 3x16-byte tables */
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buf += 48;
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if ((ret = ff_get_buffer(avctx, frame, 0)) < 0)
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return ret;
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Y = frame->data[0];
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U = frame->data[1];
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V = frame->data[2];
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/* iterate through each line in the height */
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for (y = 0; y < avctx->height; y++) {
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/* reset predictors */
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val = *buf++;
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U[0] = val & 0xF0;
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Y[0] = val << 4;
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val = *buf++;
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V[0] = val & 0xF0;
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Y[1] = Y[0] + delta_table[val & 0xF];
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Y += 2; U++; V++;
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/* iterate through the remaining pixel groups (4 pixels/group) */
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for (x = 1; x < (avctx->width >> 1); x++) {
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val = *buf++;
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U[0] = U[-1] + delta_table[val >> 4];
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Y[0] = Y[-1] + delta_table[val & 0xF];
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val = *buf++;
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V[0] = V[-1] + delta_table[val >> 4];
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Y[1] = Y[ 0] + delta_table[val & 0xF];
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Y += 2; U++; V++;
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}
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Y += frame->linesize[0] - avctx->width;
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U += frame->linesize[1] - (avctx->width >> 1);
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V += frame->linesize[2] - (avctx->width >> 1);
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}
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*got_frame = 1;
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return pkt->size;
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}
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const FFCodec ff_aura2_decoder = {
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.p.name = "aura2",
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.p.long_name = NULL_IF_CONFIG_SMALL("Auravision Aura 2"),
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.p.type = AVMEDIA_TYPE_VIDEO,
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.p.id = AV_CODEC_ID_AURA2,
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.init = aura_decode_init,
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FF_CODEC_DECODE_CB(aura_decode_frame),
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.p.capabilities = AV_CODEC_CAP_DR1,
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.caps_internal = FF_CODEC_CAP_INIT_THREADSAFE,
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};
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