[FFmpeg-devel,v5] avcodec: add farbfeld encoder

farbfeld is an uncompressed image format that is a part of suckless
tools (https://tools.suckless.org).

Its documentation is available at https://tools.suckless.org/farbfeld.

Add support for this image format in avcodec and update the image2
format accordingly.

Signed-off-by: Marcus B Spencer <marcus@marcusspencer.xyz>
---
 Changelog                 |  1 +
 doc/general_contents.texi |  2 +
 libavcodec/Makefile       |  1 +
 libavcodec/allcodecs.c    |  1 +
 libavcodec/codec_desc.c   |  7 ++++
 libavcodec/codec_id.h     |  1 +
 libavcodec/farbfeldenc.c  | 84 +++++++++++++++++++++++++++++++++++++++
 libavcodec/version.h      |  2 +-
 libavformat/img2.c        |  1 +
 libavformat/img2enc.c     |  2 +-
 10 files changed, 100 insertions(+), 2 deletions(-)
 create mode 100644 libavcodec/farbfeldenc.c

Marcus B Spencer:
> farbfeld is an uncompressed image format that is a part of suckless
> tools (https://tools.suckless.org).
> 
> Its documentation is available at https://tools.suckless.org/farbfeld.
> 
> Add support for this image format in avcodec and update the image2
> format accordingly.
> 
> Signed-off-by: Marcus B Spencer <marcus@marcusspencer.xyz>
> ---
>  Changelog                 |  1 +
>  doc/general_contents.texi |  2 +
>  libavcodec/Makefile       |  1 +
>  libavcodec/allcodecs.c    |  1 +
>  libavcodec/codec_desc.c   |  7 ++++
>  libavcodec/codec_id.h     |  1 +
>  libavcodec/farbfeldenc.c  | 84 +++++++++++++++++++++++++++++++++++++++
>  libavcodec/version.h      |  2 +-
>  libavformat/img2.c        |  1 +
>  libavformat/img2enc.c     |  2 +-
>  10 files changed, 100 insertions(+), 2 deletions(-)
>  create mode 100644 libavcodec/farbfeldenc.c
> 
> diff --git a/Changelog b/Changelog
> index 03d6b29ad8..d2b831c623 100644
> --- a/Changelog
> +++ b/Changelog
> @@ -12,6 +12,7 @@ version <next>:
>  - qsv_params option added for QSV encoders
>  - VVC decoder compatible with DVB test content
>  - xHE-AAC decoder
> +- farbfeld encoder
>  
>  
>  version 7.0:
> diff --git a/doc/general_contents.texi b/doc/general_contents.texi
> index e7cf4f8239..129a325ecf 100644
> --- a/doc/general_contents.texi
> +++ b/doc/general_contents.texi
> @@ -853,6 +853,8 @@ following image formats are supported:
>      @tab X PixMap image format
>  @item XWD  @tab X @tab X
>      @tab X Window Dump image format
> +@item FF           @tab X @tab
> +    @tab farbfeld uncompressed image format
>  @end multitable
>  
>  @code{X} means that the feature in that column (encoding / decoding) is supported.
> diff --git a/libavcodec/Makefile b/libavcodec/Makefile
> index 8ab4398b6c..9647279423 100644
> --- a/libavcodec/Makefile
> +++ b/libavcodec/Makefile
> @@ -356,6 +356,7 @@ OBJS-$(CONFIG_ESCAPE130_DECODER)       += escape130.o
>  OBJS-$(CONFIG_EVRC_DECODER)            += evrcdec.o acelp_vectors.o lsp.o
>  OBJS-$(CONFIG_EXR_DECODER)             += exr.o exrdsp.o half2float.o
>  OBJS-$(CONFIG_EXR_ENCODER)             += exrenc.o float2half.o
> +OBJS-$(CONFIG_FARBFELD_ENCODER)        += farbfeldenc.o
>  OBJS-$(CONFIG_FASTAUDIO_DECODER)       += fastaudio.o
>  OBJS-$(CONFIG_FFV1_DECODER)            += ffv1dec.o ffv1.o
>  OBJS-$(CONFIG_FFV1_ENCODER)            += ffv1enc.o ffv1.o
> diff --git a/libavcodec/allcodecs.c b/libavcodec/allcodecs.c
> index b102a8069e..b0ebb72396 100644
> --- a/libavcodec/allcodecs.c
> +++ b/libavcodec/allcodecs.c
> @@ -115,6 +115,7 @@ extern const FFCodec ff_escape124_decoder;
>  extern const FFCodec ff_escape130_decoder;
>  extern const FFCodec ff_exr_encoder;
>  extern const FFCodec ff_exr_decoder;
> +extern const FFCodec ff_farbfeld_encoder;
>  extern const FFCodec ff_ffv1_encoder;
>  extern const FFCodec ff_ffv1_decoder;
>  extern const FFCodec ff_ffvhuff_encoder;
> diff --git a/libavcodec/codec_desc.c b/libavcodec/codec_desc.c
> index a28ef68061..33dbd2ce94 100644
> --- a/libavcodec/codec_desc.c
> +++ b/libavcodec/codec_desc.c
> @@ -1959,6 +1959,13 @@ static const AVCodecDescriptor codec_descriptors[] = {
>          .long_name = NULL_IF_CONFIG_SMALL("LEAD MCMP"),
>          .props     = AV_CODEC_PROP_INTRA_ONLY | AV_CODEC_PROP_LOSSY,
>      },
> +    {
> +        .id        = AV_CODEC_ID_FARBFELD,
> +        .type      = AVMEDIA_TYPE_VIDEO,
> +        .name      = "farbfeld",
> +        .long_name = NULL_IF_CONFIG_SMALL("farbfeld uncompressed image"),
> +        .props     = AV_CODEC_PROP_INTRA_ONLY | AV_CODEC_PROP_LOSSLESS,
> +    },
>  
>      /* various PCM "codecs" */
>      {
> diff --git a/libavcodec/codec_id.h b/libavcodec/codec_id.h
> index 0ab1e34a61..d4b0d23f7e 100644
> --- a/libavcodec/codec_id.h
> +++ b/libavcodec/codec_id.h
> @@ -322,6 +322,7 @@ enum AVCodecID {
>      AV_CODEC_ID_RTV1,
>      AV_CODEC_ID_VMIX,
>      AV_CODEC_ID_LEAD,
> +    AV_CODEC_ID_FARBFELD,
>  
>      /* various PCM "codecs" */
>      AV_CODEC_ID_FIRST_AUDIO = 0x10000,     ///< A dummy id pointing at the start of audio codecs
> diff --git a/libavcodec/farbfeldenc.c b/libavcodec/farbfeldenc.c
> new file mode 100644
> index 0000000000..4ba1c97c70
> --- /dev/null
> +++ b/libavcodec/farbfeldenc.c
> @@ -0,0 +1,84 @@
> +/*
> + * Copyright (c) 2024 Marcus B Spencer <marcus@marcusspencer.xyz>
> + *
> + * Permission is hereby granted, free of charge, to any person obtaining a copy
> + * of this software and associated documentation files (the “Software”), to
> + * deal in the Software without restriction, including without limitation the
> + * rights to use, copy, modify, merge, publish, distribute, sublicense, and/or
> + * sell copies of the Software, and to permit persons to whom the Software is
> + * furnished to do so, subject to the following conditions:
> + *
> + * The above copyright notice and this permission notice shall be included in
> + * all copies or substantial portions of the Software.
> + *
> + * THE SOFTWARE IS PROVIDED “AS IS”, WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
> + * IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
> + * FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE
> + * AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
> + * LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING
> + * FROM, OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS
> + * IN THE SOFTWARE.
> + */
> +
> +#include "libavutil/imgutils.h"
> +#include "codec_internal.h"
> +#include "bytestream.h"
> +#include "avcodec.h"
> +#include "encode.h"

Should be alphabetic

> +
> +#define HEADER_SIZE 16
> +
> +static int farbfeld_encode_frame(AVCodecContext *ctx, AVPacket *pkt,
> +                                 const AVFrame *p, int *got_packet)
> +{
> +    int raw_img_size = av_image_get_buffer_size(
> +        p->format,
> +        p->width,
> +        p->height,
> +        1
> +    );
> +    int64_t buf_size = (int64_t)raw_img_size + HEADER_SIZE;
> +    uint8_t *buf;
> +    int ret;
> +
> +    if (buf_size < 0)
> +        return buf_size;

You should actually check raw_img_size (it may be possible that
av_image_get_buffer() returned an error in the range -HEADER_SIZE..-1
which would be interpreted as success by the above check).

> +
> +    if ((ret = ff_get_encode_buffer(ctx, pkt, buf_size, 0)) < 0)
> +        return ret;
> +
> +    buf = pkt->data;
> +
> +    bytestream_put_buffer(&buf, "farbfeld", 8);
> +
> +    bytestream_put_be32(&buf, ctx->width);
> +    bytestream_put_be32(&buf, ctx->height);
> +
> +    av_image_copy_to_buffer(
> +        buf,
> +        raw_img_size,
> +        (const uint8_t *const *)p->data,
> +        p->linesize,
> +        p->format,
> +        p->width,
> +        p->height,
> +        1
> +    );
> +
> +    *got_packet = 1;
> +
> +    return 0;
> +}
> +
> +const FFCodec ff_farbfeld_encoder = {
> +    .p.name         = "farbfeld",
> +    CODEC_LONG_NAME("farbfeld uncompressed image"),
> +    .p.type         = AVMEDIA_TYPE_VIDEO,
> +    .p.id           = AV_CODEC_ID_FARBFELD,
> +    .p.capabilities = AV_CODEC_CAP_DR1,
> +    FF_CODEC_ENCODE_CB(farbfeld_encode_frame),
> +    .p.pix_fmts     = (const enum AVPixelFormat[]){
> +        AV_PIX_FMT_RGBA64BE,
> +        AV_PIX_FMT_NONE
> +    },
> +};
> diff --git a/libavcodec/version.h b/libavcodec/version.h
> index da54f87887..7acb261bb3 100644
> --- a/libavcodec/version.h
> +++ b/libavcodec/version.h
> @@ -29,7 +29,7 @@
>  
>  #include "version_major.h"
>  
> -#define LIBAVCODEC_VERSION_MINOR   6
> +#define LIBAVCODEC_VERSION_MINOR   7
>  #define LIBAVCODEC_VERSION_MICRO 100
>  
>  #define LIBAVCODEC_VERSION_INT  AV_VERSION_INT(LIBAVCODEC_VERSION_MAJOR, \
> diff --git a/libavformat/img2.c b/libavformat/img2.c
> index 9981867f82..77edc7ff9b 100644
> --- a/libavformat/img2.c
> +++ b/libavformat/img2.c
> @@ -95,6 +95,7 @@
>      TAG(QOI,             qoi      ) \
>      TAG(RADIANCE_HDR,    hdr      ) \
>      TAG(WBMP,            wbmp     ) \
> +    TAG(FARBFELD,        ff       ) \
>      TAG(NONE,                     )
>  
>  #define LENGTH_CHECK(CODECID, STR) \
> diff --git a/libavformat/img2enc.c b/libavformat/img2enc.c
> index 526a11e5ee..13355a6fad 100644
> --- a/libavformat/img2enc.c
> +++ b/libavformat/img2enc.c
> @@ -276,7 +276,7 @@ const FFOutputFormat ff_image2_muxer = {
>      .p.long_name    = NULL_IF_CONFIG_SMALL("image2 sequence"),
>      .p.extensions   = "bmp,dpx,exr,jls,jpeg,jpg,jxl,ljpg,pam,pbm,pcx,pfm,pgm,pgmyuv,phm,"
>                        "png,ppm,sgi,tga,tif,tiff,jp2,j2c,j2k,xwd,sun,ras,rs,im1,im8,"
> -                      "im24,sunras,vbn,xbm,xface,pix,y,avif,qoi,hdr,wbmp",
> +                      "im24,sunras,vbn,xbm,xface,pix,y,avif,qoi,hdr,wbmp,ff",
>      .priv_data_size = sizeof(VideoMuxData),
>      .p.video_codec  = AV_CODEC_ID_MJPEG,
>      .write_header   = write_header,