[FFmpeg-devel] [PATCH] avcodec/qtrle: return last frame even if unchanged

Hendrik Leppkes h.leppkes at gmail.com
Wed May 15 23:53:25 EEST 2019


On Wed, May 15, 2019 at 8:41 PM Michael Niedermayer
<michael at niedermayer.cc> wrote:
>
> Fixes: Ticket7880
>
> Signed-off-by: Michael Niedermayer <michael at niedermayer.cc>
> ---
>  libavcodec/qtrle.c        | 27 +++++++++++++++++++++++++--
>  tests/ref/fate/qtrle-8bit |  1 +
>  2 files changed, 26 insertions(+), 2 deletions(-)
>
> diff --git a/libavcodec/qtrle.c b/libavcodec/qtrle.c
> index 2c29547e5a..11226cb842 100644
> --- a/libavcodec/qtrle.c
> +++ b/libavcodec/qtrle.c
> @@ -45,6 +45,7 @@ typedef struct QtrleContext {
>
>      GetByteContext g;
>      uint32_t pal[256];
> +    int need_flush;
>  } QtrleContext;
>
>  #define CHECK_PIXEL_PTR(n)                                                            \
> @@ -444,6 +445,12 @@ static av_cold int qtrle_decode_init(AVCodecContext *avctx)
>      return 0;
>  }
>
> +static void qtrle_flush(AVCodecContext *avctx){
> +    QtrleContext *s = avctx->priv_data;
> +
> +    s->need_flush = 0;
> +}
> +
>  static int qtrle_decode_frame(AVCodecContext *avctx,
>                                void *data, int *got_frame,
>                                AVPacket *avpkt)
> @@ -454,11 +461,26 @@ static int qtrle_decode_frame(AVCodecContext *avctx,
>      int has_palette = 0;
>      int ret, size;
>
> +    if (!avpkt->data) {
> +        if (s->need_flush) {
> +            s->need_flush = 0;
> +            if ((ret = ff_reget_buffer(avctx, s->frame)) < 0)
> +                return ret;
> +            if ((ret = av_frame_ref(data, s->frame)) < 0)
> +                return ret;
> +            *got_frame = 1;
> +        }
> +        return 0;
> +    }
> +
>      bytestream2_init(&s->g, avpkt->data, avpkt->size);
>
>      /* check if this frame is even supposed to change */
> -    if (avpkt->size < 8)
> +    if (avpkt->size < 8) {
> +        s->need_flush = 1;
>          return avpkt->size;
> +    }
> +    s->need_flush = 0;
>
>      /* start after the chunk size */
>      size = bytestream2_get_be32(&s->g) & 0x3FFFFFFF;
> @@ -572,5 +594,6 @@ AVCodec ff_qtrle_decoder = {
>      .init           = qtrle_decode_init,
>      .close          = qtrle_decode_end,
>      .decode         = qtrle_decode_frame,
> -    .capabilities   = AV_CODEC_CAP_DR1,
> +    .flush          = qtrle_flush,
> +    .capabilities   = AV_CODEC_CAP_DR1 | AV_CODEC_CAP_DELAY,
>  };
> diff --git a/tests/ref/fate/qtrle-8bit b/tests/ref/fate/qtrle-8bit
> index 27bb8aad71..39a03b7b6c 100644
> --- a/tests/ref/fate/qtrle-8bit
> +++ b/tests/ref/fate/qtrle-8bit
> @@ -61,3 +61,4 @@
>  0,        160,        160,        1,   921600, 0xcfd6ad2b
>  0,        163,        163,        1,   921600, 0x3b372379
>  0,        165,        165,        1,   921600, 0x36f245f5
> +0,        166,        166,        1,   921600, 0x36f245f5

Does this actually work if there is a gap between the last frame and
the previously changed frame?
I'm not sure where it would save the proper timestamp.

- Hendrik


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