[FFmpeg-devel] [PATCH 2/3] avcodec: add SGA Video decoder

[James Almer]

On 2/26/2021 8:29 AM, Paul B Mahol wrote:
> Signed-off-by: Paul B Mahol <onemda at gmail.com>
> ---
>   libavcodec/Makefile     |   1 +
>   libavcodec/allcodecs.c  |   1 +
>   libavcodec/codec_desc.c |   7 +
>   libavcodec/codec_id.h   |   1 +
>   libavcodec/sga.c        | 534 ++++++++++++++++++++++++++++++++++++++++
>   5 files changed, 544 insertions(+)
>   create mode 100644 libavcodec/sga.c
> 
> diff --git a/libavcodec/Makefile b/libavcodec/Makefile
> index fe7026c1db..850657ae3c 100644
> --- a/libavcodec/Makefile
> +++ b/libavcodec/Makefile
> @@ -609,6 +609,7 @@ OBJS-$(CONFIG_SANM_DECODER)            += sanm.o
>   OBJS-$(CONFIG_SCPR_DECODER)            += scpr.o
>   OBJS-$(CONFIG_SCREENPRESSO_DECODER)    += screenpresso.o
>   OBJS-$(CONFIG_SDX2_DPCM_DECODER)       += dpcm.o
> +OBJS-$(CONFIG_SGA_DECODER)             += sga.o
>   OBJS-$(CONFIG_SGI_DECODER)             += sgidec.o
>   OBJS-$(CONFIG_SGI_ENCODER)             += sgienc.o rle.o
>   OBJS-$(CONFIG_SGIRLE_DECODER)          += sgirledec.o
> diff --git a/libavcodec/allcodecs.c b/libavcodec/allcodecs.c
> index 990998b64b..a04faead16 100644
> --- a/libavcodec/allcodecs.c
> +++ b/libavcodec/allcodecs.c
> @@ -289,6 +289,7 @@ extern AVCodec ff_s302m_decoder;
>   extern AVCodec ff_sanm_decoder;
>   extern AVCodec ff_scpr_decoder;
>   extern AVCodec ff_screenpresso_decoder;
> +extern AVCodec ff_sga_decoder;
>   extern AVCodec ff_sgi_encoder;
>   extern AVCodec ff_sgi_decoder;
>   extern AVCodec ff_sgirle_decoder;
> diff --git a/libavcodec/codec_desc.c b/libavcodec/codec_desc.c
> index f64ba488f2..17f8a14044 100644
> --- a/libavcodec/codec_desc.c
> +++ b/libavcodec/codec_desc.c
> @@ -1849,6 +1849,13 @@ static const AVCodecDescriptor codec_descriptors[] = {
>           .long_name = NULL_IF_CONFIG_SMALL("Simbiosis Interactive IMX Video"),
>           .props     = AV_CODEC_PROP_LOSSY,
>       },
> +    {
> +        .id        = AV_CODEC_ID_SGA_VIDEO,
> +        .type      = AVMEDIA_TYPE_VIDEO,
> +        .name      = "sga",
> +        .long_name = NULL_IF_CONFIG_SMALL("Digital Pictures SGA Video"),
> +        .props     = AV_CODEC_PROP_LOSSY,
> +    },
>   
>       /* various PCM "codecs" */
>       {
> diff --git a/libavcodec/codec_id.h b/libavcodec/codec_id.h
> index 7dd316afd2..ab7bc68ee2 100644
> --- a/libavcodec/codec_id.h
> +++ b/libavcodec/codec_id.h
> @@ -306,6 +306,7 @@ enum AVCodecID {
>       AV_CODEC_ID_ARGO,
>       AV_CODEC_ID_CRI,
>       AV_CODEC_ID_SIMBIOSIS_IMX,
> +    AV_CODEC_ID_SGA_VIDEO,
>   
>       /* various PCM "codecs" */
>       AV_CODEC_ID_FIRST_AUDIO = 0x10000,     ///< A dummy id pointing at the start of audio codecs
> diff --git a/libavcodec/sga.c b/libavcodec/sga.c
> new file mode 100644
> index 0000000000..00752a5843
> --- /dev/null
> +++ b/libavcodec/sga.c

sgadec.c?

[...]

> +    memcpy(frame->data[1], s->pal, AVPALETTE_SIZE);
> +    frame->palette_has_changed = 1;
> +    frame->pict_type = AV_PICTURE_TYPE_I;

Missing intra only in codec_desc.c, then?

> +    frame->key_frame = 1;

The demuxer does not seem to set every packet as key frame, only some. 
Which is it?

> +
> +    *got_frame = 1;
> +
> +    return avpkt->size;
> +}
> +
> +static av_cold int sga_decode_end(AVCodecContext *avctx)
> +{
> +    SGAVideoContext *s = avctx->priv_data;
> +
> +    av_freep(&s->tileindex_data);
> +    s->tileindex_size = 0;
> +
> +    av_freep(&s->palmapindex_data);
> +    s->palmapindex_size = 0;
> +
> +    return 0;
> +}
> +
> +AVCodec ff_sga_decoder = {
> +    .name           = "sga",
> +    .long_name      = NULL_IF_CONFIG_SMALL("Digital Pictures SGA Video"),
> +    .type           = AVMEDIA_TYPE_VIDEO,
> +    .id             = AV_CODEC_ID_SGA_VIDEO,
> +    .priv_data_size = sizeof(SGAVideoContext),
> +    .init           = sga_decode_init,
> +    .decode         = sga_decode_frame,
> +    .close          = sga_decode_end,
> +    .capabilities   = AV_CODEC_CAP_DR1,
> +    .caps_internal  = FF_CODEC_CAP_INIT_THREADSAFE,
> +};
>