[FFmpeg-devel] [PATCH] mjpegdec: Fill raw huffman tables with default values too
Mark Thompson
sw at jkqxz.net
Sun Nov 11 18:26:38 EET 2018
These may be used by hwaccel decoders when the standard tables are not
otherwise available. At the same time, clean up that code into an array
so it's a little less repetitive.
---
On 29/10/18 10:26, Jun Zhao wrote:
> From: Jun Zhao <jun.zhao at intel.com>
>
> Now VA-API HWAccel MJPEG decoding uninitialized huffman table, it's
> will lead to the decoding error like"Failed to sync surface 0x5: 23
> (internal decoding error)." in iHD open source driver.
>
> Signed-off-by: dlin2 <decai.lin at intel.com>
> Signed-off-by: Jun Zhao <jun.zhao at intel.com>
> ---
> libavcodec/mjpegdec.c | 19 +++++++++++++++++++
> 1 files changed, 19 insertions(+), 0 deletions(-)
>
> diff --git a/libavcodec/mjpegdec.c b/libavcodec/mjpegdec.c
> index b0cb3ff..89effb6 100644
> --- a/libavcodec/mjpegdec.c
> +++ b/libavcodec/mjpegdec.c
> @@ -75,6 +75,25 @@ static int build_vlc(VLC *vlc, const uint8_t *bits_table,
> static int build_basic_mjpeg_vlc(MJpegDecodeContext *s)
> {
> int ret;
> + int i;
> +
> + /* initialize default huffman tables */
> + for (i = 0; i < 16; i++)
> + s->raw_huffman_lengths[0][0][i] = avpriv_mjpeg_bits_dc_luminance[i + 1];
> + for (i = 0; i < 12; i++)
> + s->raw_huffman_values[0][0][i] = avpriv_mjpeg_val_dc[i];
> + for (i = 0; i < 16; i++)
> + s->raw_huffman_lengths[0][1][i] = avpriv_mjpeg_bits_dc_chrominance[i + 1];
> + for (i = 0; i < 12; i++)
> + s->raw_huffman_values[0][1][i] = avpriv_mjpeg_val_dc[i];
> + for (i = 0; i < 16; i++)
> + s->raw_huffman_lengths[1][0][i] = avpriv_mjpeg_bits_ac_luminance[i + 1];
> + for (i = 0; i < 162; i++)
> + s->raw_huffman_values[1][0][i] = avpriv_mjpeg_val_ac_luminance[i];
> + for (i = 0; i < 16; i++)
> + s->raw_huffman_lengths[1][1][i] = avpriv_mjpeg_bits_ac_chrominance[i + 1];
> + for (i = 0; i < 162; i++)
> + s->raw_huffman_values[1][1][i] = avpriv_mjpeg_val_ac_chrominance[i];
>
> if ((ret = build_vlc(&s->vlcs[0][0], avpriv_mjpeg_bits_dc_luminance,
> avpriv_mjpeg_val_dc, 12, 0, 0)) < 0)
>
Seems reasonable, but perhaps the enclosed patch instead makes it clearer what is going on and easier to verify correctness?
(Even better: the builtin tables would be in DHT form and we would just call decode_dht() on them and avoid messing around with separate code, but since they are used in multiple places that looks more inconvenient to arrange.)
- Mark
libavcodec/mjpegdec.c | 67 +++++++++++++++++++++++++------------------
1 file changed, 39 insertions(+), 28 deletions(-)
diff --git a/libavcodec/mjpegdec.c b/libavcodec/mjpegdec.c
index 96c425515a..2f1635838a 100644
--- a/libavcodec/mjpegdec.c
+++ b/libavcodec/mjpegdec.c
@@ -73,34 +73,45 @@ static int build_vlc(VLC *vlc, const uint8_t *bits_table,
huff_code, 2, 2, huff_sym, 2, 2, use_static);
}
-static int build_basic_mjpeg_vlc(MJpegDecodeContext *s)
+static int init_default_huffman_tables(MJpegDecodeContext *s)
{
- int ret;
-
- if ((ret = build_vlc(&s->vlcs[0][0], avpriv_mjpeg_bits_dc_luminance,
- avpriv_mjpeg_val_dc, 12, 0, 0)) < 0)
- return ret;
-
- if ((ret = build_vlc(&s->vlcs[0][1], avpriv_mjpeg_bits_dc_chrominance,
- avpriv_mjpeg_val_dc, 12, 0, 0)) < 0)
- return ret;
-
- if ((ret = build_vlc(&s->vlcs[1][0], avpriv_mjpeg_bits_ac_luminance,
- avpriv_mjpeg_val_ac_luminance, 251, 0, 1)) < 0)
- return ret;
-
- if ((ret = build_vlc(&s->vlcs[1][1], avpriv_mjpeg_bits_ac_chrominance,
- avpriv_mjpeg_val_ac_chrominance, 251, 0, 1)) < 0)
- return ret;
-
- if ((ret = build_vlc(&s->vlcs[2][0], avpriv_mjpeg_bits_ac_luminance,
- avpriv_mjpeg_val_ac_luminance, 251, 0, 0)) < 0)
- return ret;
-
- if ((ret = build_vlc(&s->vlcs[2][1], avpriv_mjpeg_bits_ac_chrominance,
- avpriv_mjpeg_val_ac_chrominance, 251, 0, 0)) < 0)
- return ret;
+ static const struct {
+ int class;
+ int index;
+ const uint8_t *bits;
+ const uint8_t *values;
+ int codes;
+ int length;
+ } ht[] = {
+ { 0, 0, avpriv_mjpeg_bits_dc_luminance,
+ avpriv_mjpeg_val_dc, 12, 12 },
+ { 0, 1, avpriv_mjpeg_bits_dc_chrominance,
+ avpriv_mjpeg_val_dc, 12, 12 },
+ { 1, 0, avpriv_mjpeg_bits_ac_luminance,
+ avpriv_mjpeg_val_ac_luminance, 251, 162 },
+ { 1, 1, avpriv_mjpeg_bits_ac_chrominance,
+ avpriv_mjpeg_val_ac_chrominance, 251, 162 },
+ { 2, 0, avpriv_mjpeg_bits_ac_luminance,
+ avpriv_mjpeg_val_ac_luminance, 251, 162 },
+ { 2, 1, avpriv_mjpeg_bits_ac_chrominance,
+ avpriv_mjpeg_val_ac_chrominance, 251, 162 },
+ };
+ int i, ret;
+
+ for (i = 0; i < FF_ARRAY_ELEMS(ht); i++) {
+ ret = build_vlc(&s->vlcs[ht[i].class][ht[i].index],
+ ht[i].bits, ht[i].values, ht[i].codes,
+ 0, ht[i].class == 1);
+ if (ret < 0)
+ return ret;
+ if (ht[i].class < 2) {
+ memcpy(s->raw_huffman_lengths[ht[i].class][ht[i].index],
+ ht[i].bits + 1, 16);
+ memcpy(s->raw_huffman_values[ht[i].class][ht[i].index],
+ ht[i].values, ht[i].length);
+ }
+ }
return 0;
}
@@ -151,7 +162,7 @@ av_cold int ff_mjpeg_decode_init(AVCodecContext *avctx)
avctx->colorspace = AVCOL_SPC_BT470BG;
s->hwaccel_pix_fmt = s->hwaccel_sw_pix_fmt = AV_PIX_FMT_NONE;
- if ((ret = build_basic_mjpeg_vlc(s)) < 0)
+ if ((ret = init_default_huffman_tables(s)) < 0)
return ret;
if (s->extern_huff) {
@@ -161,7 +172,7 @@ av_cold int ff_mjpeg_decode_init(AVCodecContext *avctx)
if (ff_mjpeg_decode_dht(s)) {
av_log(avctx, AV_LOG_ERROR,
"error using external huffman table, switching back to internal\n");
- build_basic_mjpeg_vlc(s);
+ init_default_huffman_tables(s);
}
}
if (avctx->field_order == AV_FIELD_BB) { /* quicktime icefloe 019 */
--
2.19.1
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