[FFmpeg-devel] [PATCH v4 1/2] libavcodec/pgxdec: Add PGX decoder

Michael Niedermayer michael at niedermayer.cc
Tue Jun 30 03:19:22 EEST 2020


On Tue, Jun 30, 2020 at 12:26:17AM +0530, gautamramk at gmail.com wrote:
> 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..9c3b18f87d
> --- /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;
> +} PGXContext;
> +
> +static int pgx_get_number(AVCodecContext *avctx, PGXContext * const s) {
> +    int ret = -1;
> +    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;
> +

> +        temp = 10 * ret + (digit - '0');

the operation is done using int, this would overflow
by the time it is assigned to 64bit its too late



> +        if (temp > INT_MAX)
> +            return -1;
> +        ret = temp;
> +    }
> +
> +    if (ret >= 0)
> +        return ret;
> +    return -1;
> +}
> +

> +static int ff_pgx_decode_header(AVCodecContext *avctx, PGXContext * s,

why does this have a ff_ prefix ?

thx

[...]
-- 
Michael     GnuPG fingerprint: 9FF2128B147EF6730BADF133611EC787040B0FAB

If you think the mosad wants you dead since a long time then you are either
wrong or dead since a long time.
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