ffmpeg/libavcodec/pdvdec.c

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/*
* PDV video format
*
* Copyright (c) 2023 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 "avcodec.h"
#include "codec_internal.h"
#include "decode.h"
#include "zlib_wrapper.h"
#include <zlib.h>
typedef struct PDVContext {
AVFrame *previous_frame;
FFZStream zstream;
} PDVContext;
static av_cold int decode_init(AVCodecContext *avctx)
{
PDVContext *s = avctx->priv_data;
avctx->pix_fmt = AV_PIX_FMT_MONOBLACK;
s->previous_frame = av_frame_alloc();
if (!s->previous_frame)
return AVERROR(ENOMEM);
return ff_inflate_init(&s->zstream, avctx);
}
static av_cold int decode_end(AVCodecContext *avctx)
{
PDVContext *s = avctx->priv_data;
av_frame_free(&s->previous_frame);
ff_inflate_end(&s->zstream);
return 0;
}
static int decode_frame(AVCodecContext *avctx, AVFrame *frame,
int *got_frame, AVPacket *avpkt)
{
PDVContext *s = avctx->priv_data;
AVFrame *prev_frame = s->previous_frame;
z_stream *const zstream = &s->zstream.zstream;
uint8_t *dst, *prev = prev_frame->data[0];
int ret, zret;
if (avctx->skip_frame >= AVDISCARD_ALL ||
(avctx->skip_frame >= AVDISCARD_NONINTRA &&
!(avpkt->flags & AV_PKT_FLAG_KEY)))
return avpkt->size;
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zret = inflateReset(zstream);
if (zret != Z_OK) {
av_log(avctx, AV_LOG_ERROR, "Could not reset inflate: %d.\n", zret);
return AVERROR_INVALIDDATA;
}
if ((ret = ff_get_buffer(avctx, frame, AV_GET_BUFFER_FLAG_REF)) < 0)
return ret;
zstream->next_in = avpkt->data;
zstream->avail_in = avpkt->size;
dst = frame->data[0];
for (int i = 0; i < avctx->height; i++) {
zstream->next_out = dst;
zstream->avail_out = (avctx->width + 7) >> 3;
zret = inflate(zstream, Z_SYNC_FLUSH);
if (zret != Z_OK && zret != Z_STREAM_END) {
av_log(avctx, AV_LOG_ERROR,
"Inflate failed with return code: %d.\n", zret);
return AVERROR_INVALIDDATA;
}
if (prev && !(avpkt->flags & AV_PKT_FLAG_KEY)) {
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for (int j = 0; j < (avctx->width + 7) >> 3; j++)
dst[j] ^= prev[j];
prev += prev_frame->linesize[0];
}
dst += frame->linesize[0];
}
av_frame_unref(s->previous_frame);
if ((ret = av_frame_ref(s->previous_frame, frame)) < 0)
return ret;
if (avpkt->flags & AV_PKT_FLAG_KEY) {
frame->flags |= AV_FRAME_FLAG_KEY;
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frame->pict_type = AV_PICTURE_TYPE_I;
} else {
frame->pict_type = AV_PICTURE_TYPE_P;
}
*got_frame = 1;
return avpkt->size;
}
static void decode_flush(AVCodecContext *avctx)
{
PDVContext *s = avctx->priv_data;
av_frame_unref(s->previous_frame);
}
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const FFCodec ff_pdv_decoder = {
.p.name = "pdv",
CODEC_LONG_NAME("PDV (PlayDate Video)"),
.priv_data_size = sizeof(PDVContext),
.p.type = AVMEDIA_TYPE_VIDEO,
.p.id = AV_CODEC_ID_PDV,
.p.capabilities = AV_CODEC_CAP_DR1,
.caps_internal = FF_CODEC_CAP_SKIP_FRAME_FILL_PARAM |
FF_CODEC_CAP_INIT_CLEANUP,
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.init = decode_init,
.close = decode_end,
.flush = decode_flush,
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FF_CODEC_DECODE_CB(decode_frame),
};