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pngenc: Add 'dpi', 'dpm' options 

Signed-off-by: Michael Niedermayer <michaelni@gmx.at>
This commit is contained in:
Andrey Utkin 2013-05-10 18:45:11 +03:00 committed by Michael Niedermayer
parent c0a30dd2e4
commit bc63a76083
2 changed files with 49 additions and 3 deletions
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13
doc/encoders.texi
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@ -777,6 +777,19 @@ Override the x264 configuration using a :-separated list of key=value parameters
Encoding avpresets for common usages are provided so they can be used with the
general presets system (e.g. passing the @code{-pre} option).
@section png
PNG image encoder.
@subsection Private options
@table @option
@item dpi @var{integer}
Set physical density of pixels, in dots per inch, unset by default
@item dpm @var{integer}
Set physical density of pixels, in dots per meter, unset by default
@end table
@section ProRes
Apple ProRes encoder.

39
libavcodec/pngenc.c
View File

@ -25,6 +25,7 @@
#include "png.h"
#include "libavutil/avassert.h"
#include "libavutil/opt.h"
/* TODO:
* - add 2, 4 and 16 bit depth support
@ -37,6 +38,7 @@
#define IOBUF_SIZE 4096
typedef struct PNGEncContext {
AVClass *class;
DSPContext dsp;
uint8_t *bytestream;
@ -48,6 +50,8 @@ typedef struct PNGEncContext {
z_stream zstream;
uint8_t buf[IOBUF_SIZE];
int dpi; ///< Physical pixel density, in dots per inch, if set
int dpm; ///< Physical pixel density, in dots per meter, if set
} PNGEncContext;
static void png_get_interlaced_row(uint8_t *dst, int row_size,
@ -331,9 +335,15 @@ static int encode_frame(AVCodecContext *avctx, AVPacket *pkt,
png_write_chunk(&s->bytestream, MKTAG('I', 'H', 'D', 'R'), s->buf, 13);
AV_WB32(s->buf, avctx->sample_aspect_ratio.num);
AV_WB32(s->buf + 4, avctx->sample_aspect_ratio.den);
s->buf[8] = 0; /* unit specifier is unknown */
if (s->dpm) {
AV_WB32(s->buf, s->dpm);
AV_WB32(s->buf + 4, s->dpm);
s->buf[8] = 1; /* unit specifier is meter */
} else {
AV_WB32(s->buf, avctx->sample_aspect_ratio.num);
AV_WB32(s->buf + 4, avctx->sample_aspect_ratio.den);
s->buf[8] = 0; /* unit specifier is unknown */
}
png_write_chunk(&s->bytestream, MKTAG('p', 'H', 'Y', 's'), s->buf, 9);
/* put the palette if needed */
@ -458,9 +468,31 @@ static av_cold int png_enc_init(AVCodecContext *avctx){
if(avctx->pix_fmt == AV_PIX_FMT_MONOBLACK)
s->filter_type = PNG_FILTER_VALUE_NONE;
if (s->dpi && s->dpm) {
av_log(avctx, AV_LOG_ERROR, "Only one of 'dpi' or 'dpm' options should be set\n");
return AVERROR(EINVAL);
} else if (s->dpi) {
s->dpm = s->dpi * 10000 / 254;
}
return 0;
}
#define OFFSET(x) offsetof(PNGEncContext, x)
#define VE AV_OPT_FLAG_VIDEO_PARAM | AV_OPT_FLAG_ENCODING_PARAM
static const AVOption options[] = {
{"dpi", "Set image resolution (in dots per inch)", OFFSET(dpi), AV_OPT_TYPE_INT, {.i64 = 0}, 0, 0x10000, VE},
{"dpm", "Set image resolution (in dots per meter)", OFFSET(dpm), AV_OPT_TYPE_INT, {.i64 = 0}, 0, 0x10000, VE},
{ NULL }
};
static const AVClass pngenc_class = {
.class_name = "PNG encoder",
.item_name = av_default_item_name,
.option = options,
.version = LIBAVUTIL_VERSION_INT,
};
AVCodec ff_png_encoder = {
.name = "png",
.type = AVMEDIA_TYPE_VIDEO,
@ -478,4 +510,5 @@ AVCodec ff_png_encoder = {
AV_PIX_FMT_MONOBLACK, AV_PIX_FMT_NONE
},
.long_name = NULL_IF_CONFIG_SMALL("PNG (Portable Network Graphics) image"),
.priv_class = &pngenc_class,
};