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libopenjpeg: introduce lowres and lowqual private options 

OpenJPEG can decode in lower resolution or decode only a number
of enhancement layers.
This commit is contained in:
Luca Barbato 2012-07-19 01:31:39 +02:00
parent 5eb9c495af
commit ce64e5bfd1
1 changed files with 28 additions and 0 deletions
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28
libavcodec/libopenjpegdec.c
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@ -24,6 +24,7 @@
* JPEG 2000 decoder using libopenjpeg
*/
#include "libavutil/opt.h"
#include "libavutil/imgutils.h"
#include "avcodec.h"
#include "libavutil/intreadwrite.h"
@ -35,8 +36,11 @@
#define JP2_SIG_VALUE 0x0D0A870A
typedef struct {
AVClass *class;
opj_dparameters_t dec_params;
AVFrame image;
int lowres;
int lowqual;
} LibOpenJPEGContext;
static int check_image_attributes(opj_image_t *image)
@ -104,6 +108,8 @@ static int libopenjpeg_decode_frame(AVCodecContext *avctx,
opj_set_event_mgr((opj_common_ptr)dec, NULL, NULL);
ctx->dec_params.cp_limit_decoding = LIMIT_TO_MAIN_HEADER;
ctx->dec_params.cp_reduce = ctx->lowres;
ctx->dec_params.cp_layer = ctx->lowqual;
// Tie decoder with decoding parameters
opj_setup_decoder(dec, &ctx->dec_params);
stream = opj_cio_open((opj_common_ptr)dec, buf, buf_size);
@ -123,6 +129,12 @@ static int libopenjpeg_decode_frame(AVCodecContext *avctx,
}
width = image->x1 - image->x0;
height = image->y1 - image->y0;
if (ctx->lowres) {
width = (width + (1 << ctx->lowres) - 1) >> ctx->lowres;
height = (height + (1 << ctx->lowres) - 1) >> ctx->lowres;
}
if(av_image_check_size(width, height, 0, avctx) < 0) {
av_log(avctx, AV_LOG_ERROR, "%dx%d dimension invalid.\n", width, height);
goto done;
@ -208,6 +220,21 @@ static av_cold int libopenjpeg_decode_close(AVCodecContext *avctx)
return 0 ;
}
#define OFFSET(x) offsetof(LibOpenJPEGContext, x)
#define VD AV_OPT_FLAG_VIDEO_PARAM | AV_OPT_FLAG_DECODING_PARAM
static const AVOption options[] = {
{ "lowqual", "Limit the number of layers used for decoding", OFFSET(lowqual), AV_OPT_TYPE_INT, { 0 }, 0, INT_MAX, VD },
{ "lowres", "Lower the decoding resolution by a power of two", OFFSET(lowres), AV_OPT_TYPE_INT, { 0 }, 0, INT_MAX, VD },
{ NULL },
};
static const AVClass class = {
.class_name = "libopenjpeg",
.item_name = av_default_item_name,
.option = options,
.version = LIBAVUTIL_VERSION_INT,
};
AVCodec ff_libopenjpeg_decoder = {
.name = "libopenjpeg",
@ -219,5 +246,6 @@ AVCodec ff_libopenjpeg_decoder = {
.decode = libopenjpeg_decode_frame,
.capabilities = CODEC_CAP_DR1 | CODEC_CAP_FRAME_THREADS,
.long_name = NULL_IF_CONFIG_SMALL("OpenJPEG based JPEG 2000 decoder"),
.priv_class = &class,
.init_thread_copy = ONLY_IF_THREADS_ENABLED(libopenjpeg_decode_init_thread_copy),
};