[FFmpeg-devel] [PATCH v6 1/2] libavcodec/pgxdec: Add PGX decoder
Gautam Ramakrishnan
gautamramk at gmail.com
Wed Jul 1 22:07:03 EEST 2020
On Wed, Jul 1, 2020 at 6:10 PM Nicolas George <george at nsup.org> wrote:
>
> gautamramk at gmail.com (12020-06-30):
> > From: Gautam Ramakrishnan <gautamramk at gmail.com>
> >
> > This patch adds a pgx decoder.
> > ---
> > Changelog | 1 +
> > doc/general.texi | 2 +
> > libavcodec/Makefile | 1 +
> > libavcodec/allcodecs.c | 1 +
> > libavcodec/codec_desc.c | 7 ++
> > libavcodec/codec_id.h | 1 +
> > libavcodec/pgxdec.c | 199 ++++++++++++++++++++++++++++++++++++++++
> > libavcodec/version.h | 2 +-
> > 8 files changed, 213 insertions(+), 1 deletion(-)
> > create mode 100644 libavcodec/pgxdec.c
> >
> > diff --git a/Changelog b/Changelog
> > index a60e7d2eb8..1bb9931c0d 100644
> > --- a/Changelog
> > +++ b/Changelog
> > @@ -4,6 +4,7 @@ releases are sorted from youngest to oldest.
> > version <next>:
> > - AudioToolbox output device
> > - MacCaption demuxer
> > +- PGX decoder
> >
> >
> > version 4.3:
> > diff --git a/doc/general.texi b/doc/general.texi
> > index ea34b963b5..53d556c56c 100644
> > --- a/doc/general.texi
> > +++ b/doc/general.texi
> > @@ -751,6 +751,8 @@ following image formats are supported:
> > @tab Portable GrayMap image
> > @item PGMYUV @tab X @tab X
> > @tab PGM with U and V components in YUV 4:2:0
>
> > + at item PGX @tab @tab X
> > + @tab PGX file decoder
> > @item PIC @tab @tab X
> > @tab Pictor/PC Paint
> > @item PNG @tab X @tab X
> > diff --git a/libavcodec/Makefile b/libavcodec/Makefile
> > index 5a6ea59715..12aa43fe51 100644
> > --- a/libavcodec/Makefile
> > +++ b/libavcodec/Makefile
> > @@ -536,6 +536,7 @@ OBJS-$(CONFIG_PGM_ENCODER) += pnmenc.o
> > OBJS-$(CONFIG_PGMYUV_DECODER) += pnmdec.o pnm.o
> > OBJS-$(CONFIG_PGMYUV_ENCODER) += pnmenc.o
> > OBJS-$(CONFIG_PGSSUB_DECODER) += pgssubdec.o
> > +OBJS-$(CONFIG_PGX_DECODER) += pgxdec.o
> > OBJS-$(CONFIG_PICTOR_DECODER) += pictordec.o cga_data.o
> > OBJS-$(CONFIG_PIXLET_DECODER) += pixlet.o
> > OBJS-$(CONFIG_PJS_DECODER) += textdec.o ass.o
> > diff --git a/libavcodec/allcodecs.c b/libavcodec/allcodecs.c
> > index fa0c08d42e..a5048290f7 100644
> > --- a/libavcodec/allcodecs.c
> > +++ b/libavcodec/allcodecs.c
> > @@ -238,6 +238,7 @@ extern AVCodec ff_pgm_encoder;
> > extern AVCodec ff_pgm_decoder;
> > extern AVCodec ff_pgmyuv_encoder;
> > extern AVCodec ff_pgmyuv_decoder;
> > +extern AVCodec ff_pgx_decoder;
> > extern AVCodec ff_pictor_decoder;
> > extern AVCodec ff_pixlet_decoder;
> > extern AVCodec ff_png_encoder;
> > diff --git a/libavcodec/codec_desc.c b/libavcodec/codec_desc.c
> > index 9f8847544f..67e0a3055c 100644
> > --- a/libavcodec/codec_desc.c
> > +++ b/libavcodec/codec_desc.c
> > @@ -1405,6 +1405,13 @@ static const AVCodecDescriptor codec_descriptors[] = {
> > .long_name = NULL_IF_CONFIG_SMALL("AVS2-P2/IEEE1857.4"),
> > .props = AV_CODEC_PROP_LOSSY,
> > },
> > + {
> > + .id = AV_CODEC_ID_PGX,
> > + .type = AVMEDIA_TYPE_VIDEO,
> > + .name = "pgx",
> > + .long_name = NULL_IF_CONFIG_SMALL("PGX (JPEG2000 Test Format)"),
> > + .props = AV_CODEC_PROP_INTRA_ONLY | AV_CODEC_PROP_LOSSLESS,
> > + },
> > {
> > .id = AV_CODEC_ID_Y41P,
> > .type = AVMEDIA_TYPE_VIDEO,
> > diff --git a/libavcodec/codec_id.h b/libavcodec/codec_id.h
> > index d885962c9c..896ecb0ce0 100644
> > --- a/libavcodec/codec_id.h
> > +++ b/libavcodec/codec_id.h
> > @@ -241,6 +241,7 @@ enum AVCodecID {
> > AV_CODEC_ID_SCREENPRESSO,
> > AV_CODEC_ID_RSCC,
> > AV_CODEC_ID_AVS2,
> > + AV_CODEC_ID_PGX,
> >
> > AV_CODEC_ID_Y41P = 0x8000,
> > AV_CODEC_ID_AVRP,
> > diff --git a/libavcodec/pgxdec.c b/libavcodec/pgxdec.c
> > new file mode 100644
> > index 0000000000..c9e07c1e55
> > --- /dev/null
> > +++ b/libavcodec/pgxdec.c
> > @@ -0,0 +1,199 @@
> > +/*
> > + * PGX image format
> > + * Copyright (c) 2020 Gautam Ramakrishnan
> > + *
> > + * 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 "internal.h"
> > +#include "bytestream.h"
> > +#include "libavutil/imgutils.h"
> > +
> > +typedef struct PGXContext {
>
> > + GetByteContext g;
>
> Double space.
>
> And this gets inited for each frame: it could be a local variable too.
>
> Or even better: get rid of the GetByteContext entirely: the way you use
> it, it brings no benefit at all.
>
> > +} PGXContext;
> > +
>
> > +static int pgx_get_number(AVCodecContext *avctx, PGXContext * const s) {
>
> Brace on separate line.
>
> No space after pointer mark. Same a few other times.
>
> Const qualifier is usually first.
>
> > + int ret = -1;
>
> Better avoid mixing values and error codes.
>
> And better use proper error code from the start, even if for now they
> are not propagated.
>
> > + char digit;
> > +
> > + while (1) {
> > + uint64_t temp;
> > + if (!bytestream2_get_bytes_left(&s->g))
> > + return -1;
> > + digit = bytestream2_get_byte(&s->g);
> > + if (digit == ' ' || digit == 0xA || digit == 0xD)
> > + break;
> > + else if (digit < '0' || digit > '9')
> > + return -1;
> > +
>
> > + if (ret < 0)
> > + ret = 0;
>
> Urgh, no! That is horrible. Just init ret do 0.
I initialized ret to -1 as a shortcut to ensure that atleast
1 digit is present. I'll make that check differently.
>
> > +
> > + temp = 10L * ret + (digit - '0');
>
> As pointed, 10L is not uint64_t, it is long. Never use long directly in
> new code. Just explicitly cast to uint64_t.
>
> But you could dispense with temp with something like:
>
> if (ret > (INT_MAX - 10) / 10)
> return AVERROR_INVALIDDATA;
>
> > + if (temp > INT_MAX)
> > + return -1;
> > + ret = temp;
> > + }
> > +
>
> > + if (ret >= 0)
> > + return ret;
> > + return -1;
>
> Looks unnecessary.
>
> > +}
> > +
> > +static int pgx_decode_header(AVCodecContext *avctx, PGXContext * s,
> > + int *depth, int *width, int *height,
> > + int *sign)
> > +{
> > + int byte;
> > +
> > + if (bytestream2_get_bytes_left(&s->g) < 6) {
> > + return AVERROR_INVALIDDATA;
> > + }
> > +
> > + bytestream2_skip(&s->g, 6);
> > +
> > + // Is the component signed?
> > + byte = bytestream2_peek_byte(&s->g);
> > + if (byte == '+') {
> > + *sign = 0;
> > + bytestream2_skip(&s->g, 1);
> > + } else if (byte == '-') {
> > + *sign = 1;
> > + bytestream2_skip(&s->g, 1);
> > + } else if (byte == 0)
> > + goto error;
> > +
> > + byte = bytestream2_peek_byte(&s->g);
> > + if (byte == ' ')
> > + bytestream2_skip(&s->g, 1);
>
> > + else if (byte == 0)
> > + goto error;
> > +
> > + *depth = pgx_get_number(avctx, s);
> > + *width = pgx_get_number(avctx, s);
> > + *height = pgx_get_number(avctx, s);
> > + if (*depth <= 0 || *width <= 0 || *height <= 0)
> > + goto error;
> > +
> > + if (bytestream2_peek_byte(&s->g) == 0xA)
> > + bytestream2_skip(&s->g, 1);
> > + return 0;
> > +
> > +error:
> > + av_log(avctx, AV_LOG_ERROR, "Error in decoding header.\n");
> > + return AVERROR_INVALIDDATA;
> > +}
> > +
> > +static inline int write_frame_8(AVPacket *avpkt, AVFrame *frame, PGXContext * const s,
> > + int width, int height, int sign, int depth)
> > +{
> > + int i, j;
> > + for (i = 0; i < height; i++) {
> > + uint8_t *line = frame->data[0] + i * frame->linesize[0];
> > + for (j = 0; j < width; j++) {
> > + int val;
>
> > + if (bytestream2_get_bytes_left(&s->g) < 1)
> > + return AVERROR_INVALIDDATA;
>
> Just test that you have enough data available from the beginning.
>
> > + if (sign)
> > + val = bytestream2_get_byte(&s->g) + (1 << (depth - 1));
> > + else
> > + val = bytestream2_get_byteu(&s->g);
>
> I am quite sure you are mistaken about the difference between get_byteu
> and get_byte.
>
> > + val <<= (8 - depth);
> > + *(line + j) = val;
> > + }
>
> > + line += frame->linesize[0];
>
> This makes no sense if line is reinited at the beginning of the loop.
>
> > + }
> > + return 0;
> > +}
> > +
> > +static inline int write_frame_16(AVPacket *avpkt, AVFrame *frame, PGXContext * const s,
> > + int width, int height, int sign, int depth)
> > +{
> > + int i, j;
> > + for (i = 0; i < height; i++) {
> > + uint16_t *line = (uint16_t*)frame->data[0] + i*frame->linesize[0]/2;
> > + for (j = 0; j < width; j++) {
> > + int val;
> > + if (bytestream2_get_bytes_left(&s->g) < 2)
> > + return AVERROR_INVALIDDATA;
> > + if (sign)
> > + val = (int16_t)bytestream2_get_be16(&s->g) + (1 << (depth - 1));
> > + else
> > + val = bytestream2_get_be16u(&s->g);
> > + val <<= (16 - depth);
> > + *(line + j) = val;
> > + }
> > + line += frame->linesize[0]/2;
> > + }
> > + return 0;
> > +}
>
> This is almost exactly the same function: factor the code.
>
> > +
> > +static int pgx_decode_frame(AVCodecContext *avctx, void *data,
> > + int *got_frame, AVPacket *avpkt)
> > +{
> > + PGXContext *s = avctx->priv_data;
> > + AVFrame *p = data;
> > + int ret;
> > + int bpp;
> > + int width, height, depth;
> > + int sign = 0;
> > + bytestream2_init(&s->g, avpkt->data, avpkt->size);
> > +
> > + if ((ret = pgx_decode_header(avctx, s, &depth, &width, &height, &sign)) < 0)
> > + return ret;
>
> > + if (ret = av_image_check_size(width, height, 0, avctx)) {
> > + av_log(avctx, AV_LOG_ERROR, "Image too large.\n");
> > + return ret;
> > + }
>
> Already covered by ff_set_dimensions().
>
> > + if ((ret = ff_set_dimensions(avctx, width, height)) < 0)
> > + return ret;
> > +
> > + if (depth <= 8) {
> > + avctx->pix_fmt = AV_PIX_FMT_GRAY8;
> > + bpp = 8;
> > + } else if (depth <= 16) {
> > + avctx->pix_fmt = AV_PIX_FMT_GRAY16BE;
> > + bpp = 16;
> > + } else {
> > + av_log(avctx, AV_LOG_ERROR, "Maximum depth of 16 bits supported.\n");
> > + return AVERROR_PATCHWELCOME;
> > + }
> > +
> > + if ((ret = ff_get_buffer(avctx, p, 0)) < 0)
> > + return ret;
>
> > + *got_frame = 1;
>
> Better set that after write_frame() has succeeded.
>
> > + p->pict_type = AV_PICTURE_TYPE_I;
> > + p->key_frame = 1;
> > + avctx->bits_per_raw_sample = depth;
>
> > + if (bpp == 8)
> > + write_frame_8(avpkt, p, s, width, height, sign, depth);
> > + else if (bpp == 16)
> > + write_frame_16(avpkt, p, s, width, height, sign, depth);
>
> You are ignoring the return value.
>
> > + return 0;
> > +}
> > +
> > +AVCodec ff_pgx_decoder = {
> > + .name = "pgx",
> > + .long_name = NULL_IF_CONFIG_SMALL("PGX (JPEG2000 Test Format)"),
> > + .type = AVMEDIA_TYPE_VIDEO,
> > + .id = AV_CODEC_ID_PGX,
> > + .priv_data_size = sizeof(PGXContext),
> > + .decode = pgx_decode_frame,
> > + .capabilities = AV_CODEC_CAP_DR1,
> > +};
> > diff --git a/libavcodec/version.h b/libavcodec/version.h
> > index 03593026b3..482cc6d6ba 100644
> > --- a/libavcodec/version.h
> > +++ b/libavcodec/version.h
> > @@ -28,7 +28,7 @@
> > #include "libavutil/version.h"
> >
> > #define LIBAVCODEC_VERSION_MAJOR 58
> > -#define LIBAVCODEC_VERSION_MINOR 93
> > +#define LIBAVCODEC_VERSION_MINOR 94
> > #define LIBAVCODEC_VERSION_MICRO 100
> >
> > #define LIBAVCODEC_VERSION_INT AV_VERSION_INT(LIBAVCODEC_VERSION_MAJOR, \
Thanks for reviewing the patch. I shall make all the changes and resubmit.
--
-------------
Gautam |
More information about the ffmpeg-devel
mailing list