Quoting Paul B Mahol (2021-03-01 15:41:22)
> Signed-off-by: Paul B Mahol <[email protected]>
> ---
> libavcodec/speedhq.c | 42 ++++++++++++++++++++++++++++++++++++++++--
> 1 file changed, 40 insertions(+), 2 deletions(-)
>
> diff --git a/libavcodec/speedhq.c b/libavcodec/speedhq.c
> index 759fc6dfc5..2a2fc42efa 100644
> --- a/libavcodec/speedhq.c
> +++ b/libavcodec/speedhq.c
> @@ -283,6 +283,7 @@ static int decode_speedhq_field(const SHQContext *s,
> const uint8_t *buf, int buf
> int linesize_cb = frame->linesize[1] * line_stride;
> int linesize_cr = frame->linesize[2] * line_stride;
> int linesize_a;
> + GetBitContext gb;
>
> if (s->alpha_type != SHQ_NO_ALPHA)
> linesize_a = frame->linesize[3] * line_stride;
> @@ -304,7 +305,6 @@ static int decode_speedhq_field(const SHQContext *s,
> const uint8_t *buf, int buf
> }
>
> for (slice_number = 0; slice_number < 4; slice_number++) {
> - GetBitContext gb;
> uint32_t slice_begin, slice_end;
> int x, y;
>
> @@ -333,7 +333,7 @@ static int decode_speedhq_field(const SHQContext *s,
> const uint8_t *buf, int buf
> dest_a = frame->data[3] + frame->linesize[3] * (y +
> field_number);
> }
>
> - for (x = 0; x < frame->width; x += 16) {
> + for (x = 0; x < frame->width - 8 * (s->subsampling !=
> SHQ_SUBSAMPLING_444); x += 16) {
> /* Decode the four luma blocks. */
> if ((ret = decode_dct_block(s, &gb, last_dc, 0, dest_y,
> linesize_y)) < 0)
> return ret;
> @@ -402,6 +402,44 @@ static int decode_speedhq_field(const SHQContext *s,
> const uint8_t *buf, int buf
> }
> }
>
> + if (s->subsampling == SHQ_SUBSAMPLING_444)
> + return 0;
> +
> + if (!(frame->width & 15))
> + return 0;
This is hard to follow. Seems to me it would be simpler to factor the
below block into a separate function and retain a single successful
return point in this one.
> +
> + for (int y = 0; y < frame->height; y += 16 * line_stride) {
> + int last_dc[4] = { 1024, 1024, 1024, 1024 };
> + uint8_t *dest_y, *dest_cb, *dest_cr;
> + int x = frame->width - 8;
> +
> + dest_y = frame->data[0] + frame->linesize[0] * (y + field_number) +
> x;
> + if (s->subsampling == SHQ_SUBSAMPLING_420) {
Commit message only says 422.
How come there's the same number of chroma blocks for 422 and 420?
> + dest_cb = frame->data[1] + frame->linesize[1] * (y/2 +
> field_number) + x / 2;
> + dest_cr = frame->data[2] + frame->linesize[2] * (y/2 +
> field_number) + x / 2;
> + } else if (s->subsampling == SHQ_SUBSAMPLING_422) {
> + dest_cb = frame->data[1] + frame->linesize[1] * (y +
> field_number) + x / 2;
> + dest_cr = frame->data[2] + frame->linesize[2] * (y +
> field_number) + x / 2;
> + }
> +
> + if ((ret = decode_dct_block(s, &gb, last_dc, 0, dest_y, linesize_y))
> < 0)
> + return ret;
> + if ((ret = decode_dct_block(s, &gb, last_dc, 0, dest_y + 8,
> linesize_y)) < 0)
> + return ret;
> + if ((ret = decode_dct_block(s, &gb, last_dc, 0, dest_y + 8 *
> linesize_y, linesize_y)) < 0)
> + return ret;
> + if ((ret = decode_dct_block(s, &gb, last_dc, 0, dest_y + 8 *
> linesize_y + 8, linesize_y)) < 0)
> + return ret;
> + if ((ret = decode_dct_block(s, &gb, last_dc, 1, dest_cb,
> linesize_cb)) < 0)
> + return ret;
> + if ((ret = decode_dct_block(s, &gb, last_dc, 2, dest_cr,
> linesize_cr)) < 0)
> + return ret;
> + if ((ret = decode_dct_block(s, &gb, last_dc, 1, dest_cb + 8 *
> linesize_cb, linesize_cb)) < 0)
> + return ret;
> + if ((ret = decode_dct_block(s, &gb, last_dc, 2, dest_cr + 8 *
> linesize_cr, linesize_cr)) < 0)
> + return ret;
> + }
> +
> return 0;
A test would be nice.
--
Anton Khirnov
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