Re: [FFmpeg-devel] [PATCH] WBMP (Wireless Application Protocol Bitmap) image format

[Andreas Rheinhardt <andreas.rheinhardt@outlook.com>]

Peter Ross:
> ---
> 
> example: https://example-files.online-convert.com/raster%20image/wbmp/example.wbmp
> 
>  Changelog                 |  1 +
>  doc/general_contents.texi |  2 +
>  libavcodec/Makefile       |  2 +
>  libavcodec/allcodecs.c    |  2 +
>  libavcodec/codec_desc.c   |  7 +++
>  libavcodec/codec_id.h     |  1 +
>  libavcodec/wbmpdec.c      | 92 +++++++++++++++++++++++++++++++++++++++
>  libavcodec/wbmpenc.c      | 91 ++++++++++++++++++++++++++++++++++++++
>  libavformat/img2.c        |  1 +
>  libavformat/img2enc.c     |  2 +-
>  tests/fate/lavf-image.mak |  1 +
>  tests/ref/lavf/wbmp       |  3 ++
>  12 files changed, 204 insertions(+), 1 deletion(-)
>  create mode 100644 libavcodec/wbmpdec.c
>  create mode 100644 libavcodec/wbmpenc.c
>  create mode 100644 tests/ref/lavf/wbmp
> 
> diff --git a/Changelog b/Changelog
> index 92780c9953..83bc36297a 100644
> --- a/Changelog
> +++ b/Changelog
> @@ -7,6 +7,7 @@ version <next>:
>  - ffmpeg -shortest_buf_duration option
>  - ffmpeg now requires threading to be built
>  - ffmpeg now runs every muxer in a separate thread
> +- WBMP (Wireless Application Protocol Bitmap) image format
>  
>  
>  version 5.1:
> diff --git a/doc/general_contents.texi b/doc/general_contents.texi
> index f25c784d3b..86ec6d606b 100644
> --- a/doc/general_contents.texi
> +++ b/doc/general_contents.texi
> @@ -801,6 +801,8 @@ following image formats are supported:
>      @tab Targa (.TGA) image format
>  @item VBN  @tab X @tab X
>      @tab Vizrt Binary Image format
> +@item WBMP         @tab X @tab X
> +    @tab Wireless Application Protocol Bitmap image format
>  @item WebP         @tab E @tab X
>      @tab WebP image format, encoding supported through external library libwebp
>  @item XBM  @tab X @tab X
> diff --git a/libavcodec/Makefile b/libavcodec/Makefile
> index ef2318438b..727db20345 100644
> --- a/libavcodec/Makefile
> +++ b/libavcodec/Makefile
> @@ -762,6 +762,8 @@ OBJS-$(CONFIG_VP9_V4L2M2M_DECODER)     += v4l2_m2m_dec.o
>  OBJS-$(CONFIG_VQA_DECODER)             += vqavideo.o
>  OBJS-$(CONFIG_WAVPACK_DECODER)         += wavpack.o wavpackdata.o dsd.o
>  OBJS-$(CONFIG_WAVPACK_ENCODER)         += wavpackdata.o wavpackenc.o
> +OBJS-$(CONFIG_WBMP_DECODER)            += wbmpdec.o
> +OBJS-$(CONFIG_WBMP_ENCODER)            += wbmpenc.o
>  OBJS-$(CONFIG_WCMV_DECODER)            += wcmv.o
>  OBJS-$(CONFIG_WEBP_DECODER)            += webp.o
>  OBJS-$(CONFIG_WEBVTT_DECODER)          += webvttdec.o ass.o
> diff --git a/libavcodec/allcodecs.c b/libavcodec/allcodecs.c
> index 31d2c5979c..c94e2d5966 100644
> --- a/libavcodec/allcodecs.c
> +++ b/libavcodec/allcodecs.c
> @@ -378,6 +378,8 @@ extern const FFCodec ff_vp9_decoder;
>  extern const FFCodec ff_vp9_rkmpp_decoder;
>  extern const FFCodec ff_vp9_v4l2m2m_decoder;
>  extern const FFCodec ff_vqa_decoder;
> +extern const FFCodec ff_wbmp_decoder;
> +extern const FFCodec ff_wbmp_encoder;
>  extern const FFCodec ff_webp_decoder;
>  extern const FFCodec ff_wcmv_decoder;
>  extern const FFCodec ff_wrapped_avframe_encoder;
> diff --git a/libavcodec/codec_desc.c b/libavcodec/codec_desc.c
> index fdcf8198fe..c1a177c22d 100644
> --- a/libavcodec/codec_desc.c
> +++ b/libavcodec/codec_desc.c
> @@ -1900,6 +1900,13 @@ static const AVCodecDescriptor codec_descriptors[] = {
>          .long_name = NULL_IF_CONFIG_SMALL("HDR (Radiance RGBE format) image"),
>          .props     = AV_CODEC_PROP_INTRA_ONLY | AV_CODEC_PROP_LOSSY,
>      },
> +    {
> +        .id        = AV_CODEC_ID_WBMP,
> +        .type      = AVMEDIA_TYPE_VIDEO,
> +        .name      = "wbmp",
> +        .long_name = NULL_IF_CONFIG_SMALL("WBMP (Wireless Application Protocol Bitmap) 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 27bf68ec1d..386a00a7ef 100644
> --- a/libavcodec/codec_id.h
> +++ b/libavcodec/codec_id.h
> @@ -313,6 +313,7 @@ enum AVCodecID {
>      AV_CODEC_ID_QOI,
>      AV_CODEC_ID_PHM,
>      AV_CODEC_ID_RADIANCE_HDR,
> +    AV_CODEC_ID_WBMP,
>  
>      /* various PCM "codecs" */
>      AV_CODEC_ID_FIRST_AUDIO = 0x10000,     ///< A dummy id pointing at the start of audio codecs
> diff --git a/libavcodec/wbmpdec.c b/libavcodec/wbmpdec.c
> new file mode 100644
> index 0000000000..cb673459f1
> --- /dev/null
> +++ b/libavcodec/wbmpdec.c
> @@ -0,0 +1,92 @@
> +/*
> + * WBMP (Wireless Application Protocol Bitmap) image
> + *
> + * 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 "bytestream.h"
> +#include "codec_internal.h"
> +#include "internal.h"
> +#include "thread.h"
> +
> +static unsigned int getv(GetByteContext * gb)
> +{
> +    int i;
> +    unsigned int v = 0;
> +
> +    do {
> +        i = bytestream2_get_byte(gb);
> +        v = (v << 7) | (i & 0x7F);
> +    } while (i & 0x80);
> +    return v;
> +}
> +
> +static void readbits(uint8_t * dst, int width, int height, int linesize, const uint8_t * src, int size)
> +{
> +    int wpad = (width + 7) / 8;
> +    for (int j = 0; j < height && size > 0; j++) {
> +        memcpy(dst, src, FFMIN(wpad, size));
> +        src += wpad;
> +        size -= wpad;
> +        dst += linesize;
> +    }
> +}
> +
> +static int wbmp_decode_frame(AVCodecContext *avctx, AVFrame *p,
> +                            int *got_frame, AVPacket *avpkt)
> +{
> +    const uint8_t *buf = avpkt->data;
> +    int buf_size = avpkt->size, width, height, ret;
> +    GetByteContext gb;
> +
> +    bytestream2_init(&gb, buf, buf_size);
> +
> +    if (getv(&gb))
> +        return AVERROR_INVALIDDATA;
> +    bytestream2_skip(&gb, 1);
> +    width = getv(&gb);
> +    height = getv(&gb);
> +
> +    if ((ret = ff_set_dimensions(avctx, width, height)) < 0)
> +        return ret;
> +
> +    avctx->pix_fmt = AV_PIX_FMT_MONOBLACK;
> +    if ((ret = ff_thread_get_buffer(avctx, p, 0)) < 0)
> +        return ret;
> + 
> +    if (p->linesize[0] == width / 8)
> +        bytestream2_get_buffer(&gb, p->data[0], width * height / 8);
> +    else
> +        readbits(p->data[0], width, height, p->linesize[0], gb.buffer, gb.buffer_end - gb.buffer_start);
> +
> +    p->key_frame = 1;
> +    p->pict_type = AV_PICTURE_TYPE_I;
> +
> +    *got_frame   = 1;
> +
> +    return buf_size;
> +}
> +
> +const FFCodec ff_wbmp_decoder = {
> +    .p.name         = "wbmp",
> +    .p.long_name    = NULL_IF_CONFIG_SMALL("WBMP (Wireless Application Protocol Bitmap) image"),
> +    .p.type         = AVMEDIA_TYPE_VIDEO,
> +    .p.id           = AV_CODEC_ID_WBMP,
> +    .p.capabilities = AV_CODEC_CAP_DR1 | AV_CODEC_CAP_FRAME_THREADS,
> +    FF_CODEC_DECODE_CB(wbmp_decode_frame),
> +};
> diff --git a/libavcodec/wbmpenc.c b/libavcodec/wbmpenc.c
> new file mode 100644
> index 0000000000..f4abc5c1a3
> --- /dev/null
> +++ b/libavcodec/wbmpenc.c
> @@ -0,0 +1,91 @@
> +/*
> + * WBMP (Wireless Application Protocol Bitmap) image
> + *
> + * 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 "bytestream.h"
> +#include "codec_internal.h"
> +#include "encode.h"
> +
> +static void putv(uint8_t ** bufp, unsigned int v)
> +{
> +    unsigned int vv = 0;
> +    int n = 0;
> +
> +    while (vv != v)
> +        vv += v & (0x7F << 7 * n++);
> +
> +    while (--n > 0)
> +        bytestream_put_byte(bufp, 0x80 | (v & (0x7F << 7 * n)) >> 7 * n);
> +
> +    bytestream_put_byte(bufp, v & 0x7F);
> +}
> +
> +static void writebits(uint8_t ** bufp, const uint8_t * src, int width, int height, int linesize)
> +{
> +    int wpad = (width + 7) / 8;
> +    for (int j = 0; j < height; j++) {
> +        memcpy(*bufp, src, wpad);
> +        *bufp += wpad;
> +        src += linesize;
> +    }
> +}
> +
> +static int wbmp_encode_frame(AVCodecContext *avctx, AVPacket *pkt,
> +                            const AVFrame *frame, int *got_packet)
> +{
> +    int64_t size = avctx->height * (avctx->width + 7) / 8 + 32;

Wouldn't height * ((width + 7) / 8) be more accurate?

> +    uint8_t *buf;
> +    int ret;
> +
> +    if ((ret = ff_get_encode_buffer(avctx, pkt, size, 0)) < 0)
> +        return ret;
> +
> +    buf = pkt->data;
> +
> +    putv(&buf, 0);
> +    bytestream_put_byte(&buf, 0);
> +    putv(&buf, avctx->width);
> +    putv(&buf, avctx->height);
> +
> +    if (frame->linesize[0] == avctx->width / 8)
> +        bytestream_put_buffer(&buf, frame->data[0], avctx->width * avctx->height / 8);

Wouldn't

if (frame->linesize[0] == (avctx->width + 7) / 8)
    bytestream_put_buffer(&buf, frame->data[0], avctx->height *
(avctx->width + 7) / 8);

work, too, even in more general scenarios than the above version?
(A similar remark can be made about the decoder.)

Anyway, I think this would be more readable if the check whether to
write in one memcpy or one memcpy per line were in writebits().

> +    else
> +        writebits(&buf, frame->data[0], avctx->width, avctx->height, frame->linesize[0]);
> +
> +    av_shrink_packet(pkt, buf - pkt->data);
> +
> +    pkt->flags |= AV_PKT_FLAG_KEY;

This is unnecessary, as the corresponding AVCodecDescriptor has the
AV_CODEC_PROP_INTRA_ONLY set, so this will be set generically.

> +
> +    *got_packet = 1;
> +    return 0;
> +}
> +
> +const FFCodec ff_wbmp_encoder = {
> +    .p.name         = "wbmp",
> +    .p.long_name    = NULL_IF_CONFIG_SMALL("WBMP (Wireless Application Protocol Bitmap) image"),
> +    .p.type         = AVMEDIA_TYPE_VIDEO,
> +    .p.id           = AV_CODEC_ID_WBMP,
> +    .p.capabilities = AV_CODEC_CAP_DR1 | AV_CODEC_CAP_FRAME_THREADS,
> +    FF_CODEC_ENCODE_CB(wbmp_encode_frame),
> +    .p.pix_fmts     = (const enum AVPixelFormat[]){
> +        AV_PIX_FMT_MONOBLACK,
> +        AV_PIX_FMT_NONE
> +    },
> +};
> diff --git a/libavformat/img2.c b/libavformat/img2.c
> index 233e83de37..06e48549ac 100644
> --- a/libavformat/img2.c
> +++ b/libavformat/img2.c
> @@ -92,6 +92,7 @@ const IdStrMap ff_img_tags[] = {
>      { AV_CODEC_ID_JPEGXL,     "jxl"      },
>      { AV_CODEC_ID_QOI,        "qoi"      },
>      { AV_CODEC_ID_RADIANCE_HDR, "hdr"    },
> +    { AV_CODEC_ID_WBMP,       "wbmp"     },
>      { AV_CODEC_ID_NONE,       NULL       }
>  };
>  
> diff --git a/libavformat/img2enc.c b/libavformat/img2enc.c
> index 40dc51b443..c05f37e22b 100644
> --- a/libavformat/img2enc.c
> +++ b/libavformat/img2enc.c
> @@ -273,7 +273,7 @@ const AVOutputFormat ff_image2_muxer = {
>      .long_name      = NULL_IF_CONFIG_SMALL("image2 sequence"),
>      .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",
> +                      "im24,sunras,vbn,xbm,xface,pix,y,avif,qoi,hdr,wbmp",
>      .priv_data_size = sizeof(VideoMuxData),
>      .video_codec    = AV_CODEC_ID_MJPEG,
>      .write_header   = write_header,
> diff --git a/tests/fate/lavf-image.mak b/tests/fate/lavf-image.mak
> index 38d3689abf..130a199127 100644
> --- a/tests/fate/lavf-image.mak
> +++ b/tests/fate/lavf-image.mak
> @@ -43,6 +43,7 @@ FATE_LAVF_IMAGES-$(call LAVF_IMAGES,     SUNRAST) += sun
>  FATE_LAVF_IMAGES-$(call LAVF_IMAGES,       TARGA) += tga
>  FATE_LAVF_IMAGES-$(call LAVF_IMAGES,        TIFF) += tiff
>  FATE_LAVF_IMAGES-$(call LAVF_IMAGES,         QOI) += qoi
> +FATE_LAVF_IMAGES-$(call LAVF_IMAGES,        WBMP) += wbmp
>  FATE_LAVF_IMAGES-$(call LAVF_IMAGES,         XBM) += xbm
>  FATE_LAVF_IMAGES-$(call LAVF_IMAGES,         XWD) += xwd
>  FATE_LAVF_IMAGES-$(call LAVF_IMAGES,         XWD) += rgba.xwd
> diff --git a/tests/ref/lavf/wbmp b/tests/ref/lavf/wbmp
> new file mode 100644
> index 0000000000..9b4b2767f6
> --- /dev/null
> +++ b/tests/ref/lavf/wbmp
> @@ -0,0 +1,3 @@
> +ebe2a887bd3098ac50502063257b4275 *tests/data/images/wbmp/02.wbmp
> +tests/data/images/wbmp/%02d.wbmp CRC=0xab19200d
> +12678 tests/data/images/wbmp/02.wbmp
> 
> 
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