[FFmpeg-devel] [PATCH]Fix decoding frwu with changed field order

[Paul B Mahol]

On 11/24/12, Carl Eugen Hoyos <cehoyos at ag.or.at> wrote:
>
> diff --git a/libavcodec/frwu.c b/libavcodec/frwu.c
> index c70013b..6e2522f 100644
> --- a/libavcodec/frwu.c
> +++ b/libavcodec/frwu.c
> @@ -22,6 +22,12 @@
>
>  #include "avcodec.h"
>  #include "bytestream.h"
> +#include "libavutil/opt.h"
> +
> +typedef struct {
> +    AVClass *av_class;
> +    int change_field_order;
> +} FRWUContext;
>
>  static av_cold int decode_init(AVCodecContext *avctx)
>  {
> @@ -41,6 +47,7 @@ static av_cold int decode_init(AVCodecContext *avctx)
>  static int decode_frame(AVCodecContext *avctx, void *data, int *data_size,
>                          AVPacket *avpkt)
>  {
> +    FRWUContext *s = avctx->priv_data;
>      int field, ret;
>      AVFrame *pic = avctx->coded_frame;
>      const uint8_t *buf = avpkt->data;
> @@ -84,9 +91,14 @@ static int decode_frame(AVCodecContext *avctx, void *data, int *data_size,
>              av_log(avctx, AV_LOG_ERROR, "Packet is too small, need %i, have %i\n", field_size, (int)(buf_end - buf));
>              return AVERROR_INVALIDDATA;
>          }
> -        if (field)
> +        if (field ^ s->change_field_order) {
>              dst += pic->linesize[0];
> +        } else if (s->change_field_order) {
> +            dst += 2 * pic->linesize[0];
> +        }
>          for (i = 0; i < field_h; i++) {
> +            if (s->change_field_order && field && i == field_h - 1)
> +                dst = pic->data[0];
>              memcpy(dst, buf, avctx->width * 2);
>              buf += avctx->width * 2;
>              dst += pic->linesize[0] << 1;
> @@ -110,13 +122,28 @@ static av_cold int decode_close(AVCodecContext *avctx)
>      return 0;
>  }
>
> +static const AVOption frwu_options[] = {
> +    {"change_field_order", "Change frwu field order", offsetof(FRWUContext, change_field_order), FF_OPT_TYPE_INT,

Why is "frwu" mandatory? It is really not.
> +     {.dbl = 0}, 0, 1, AV_OPT_FLAG_DECODING_PARAM | AV_OPT_FLAG_VIDEO_PARAM},
> +    {NULL}
> +};
> +
> +static const AVClass frwu_class = {
> +    "frwu Decoder",
> +    av_default_item_name,
> +    frwu_options,
> +    LIBAVUTIL_VERSION_INT,

Plese use designated initializers.
> +};
> +
>  AVCodec ff_frwu_decoder = {
>      .name           = "frwu",
>      .type           = AVMEDIA_TYPE_VIDEO,
>      .id             = AV_CODEC_ID_FRWU,
> +    .priv_data_size = sizeof(FRWUContext),
>      .init           = decode_init,
>      .close          = decode_close,
>      .decode         = decode_frame,
>      .capabilities   = CODEC_CAP_DR1,
>      .long_name      = NULL_IF_CONFIG_SMALL("Forward Uncompressed"),
> +    .priv_class     = &frwu_class,
>  };

Otherwise lgtm if tested under valgrind.