sherpa-ffmpeg-patch

diff --git a/libavcodec/j2kdec.c b/libavcodec/j2kdec.c
index 683062d..3e78b0b 100644
--- a/libavcodec/j2kdec.c
+++ b/libavcodec/j2kdec.c
@@ -30,6 +30,7 @@
 #include "avcodec.h"
 #include "bytestream.h"
 #include "internal.h"
+#include "thread.h"
 #include "j2k.h"
 #include "libavutil/common.h"

@@ -205,6 +206,7 @@ static int tag_tree_decode(J2kDecoderContext *s, J2kTgtNode *node, int threshold
 static int get_siz(J2kDecoderContext *s)
 {
     int i, ret;
+    ThreadFrame frame = { .f = s->picture };

     if (bytestream2_get_bytes_left(&s->g) < 36)
         return AVERROR(EINVAL);
@@ -282,7 +284,7 @@ static int get_siz(J2kDecoderContext *s)
     }


-    if ((ret = ff_get_buffer(s->avctx, s->picture, 0)) < 0)
+    if ((ret = ff_thread_get_buffer(s->avctx, &frame, 0)) < 0)
         return ret;

     s->picture->pict_type = AV_PICTURE_TYPE_I;
@@ -1088,6 +1090,6 @@ AVCodec ff_j2k_decoder = {
     .priv_data_size = sizeof(J2kDecoderContext),
     .init           = j2kdec_init,
     .decode         = decode_frame,
-    .capabilities   = CODEC_CAP_EXPERIMENTAL,
+    .capabilities   = CODEC_CAP_EXPERIMENTAL | CODEC_CAP_FRAME_THREADS,
     .long_name      = NULL_IF_CONFIG_SMALL("JPEG 2000"),
 };
diff --git a/libavcodec/jpeg2000dec.c b/libavcodec/jpeg2000dec.c
index 20e5c9c..7b902fa 100644
--- a/libavcodec/jpeg2000dec.c
+++ b/libavcodec/jpeg2000dec.c
@@ -86,9 +86,6 @@ typedef struct Jpeg2000DecoderContext {
     int16_t         curtileno;
     Jpeg2000Tile    *tile;

-    /*options parameters*/
-    int16_t         lowres;
-    int16_t         reduction_factor;
 } Jpeg2000DecoderContext;

 /* get_bits functions for JPEG2000 packet bitstream
@@ -205,9 +202,9 @@ static int get_siz(Jpeg2000DecoderContext *s)

     /* compute image size with reduction factor */
     s->avctx->width  = ff_jpeg2000_ceildivpow2(s->width  - s->image_offset_x,
-                                               s->reduction_factor);
+                                               s->avctx->lowres);
     s->avctx->height = ff_jpeg2000_ceildivpow2(s->height - s->image_offset_y,
-                                               s->reduction_factor);
+                                               s->avctx->lowres);

     switch (s->avctx->profile) {
     case FF_PROFILE_JPEG2000_DCINEMA_2K:
@@ -254,10 +251,10 @@ static int get_cox(Jpeg2000DecoderContext *s, Jpeg2000CodingStyle *c)
     c->nreslevels = bytestream_get_byte(&s->buf) + 1; // num of resolution levels - 1

     /* compute number of resolution levels to decode */
-    if (c->nreslevels < s->reduction_factor)
+    if (c->nreslevels < s->avctx->lowres)
         c->nreslevels2decode = 1;
     else
-        c->nreslevels2decode = c->nreslevels - s->reduction_factor;
+        c->nreslevels2decode = c->nreslevels - s->avctx->lowres;

     c->log2_cblk_width  = bytestream_get_byte(&s->buf) + 2; // cblk width
     c->log2_cblk_height = bytestream_get_byte(&s->buf) + 2; // cblk height
@@ -635,7 +632,14 @@ static int jpeg2000_decode_packet(Jpeg2000DecoderContext *s,
             Jpeg2000Cblk *cblk = prec->cblk + cblkno;
             if (s->buf_end - s->buf < cblk->lengthinc)
                 return AVERROR(EINVAL);
-            bytestream_get_buffer(&s->buf, cblk->data, cblk->lengthinc);
+            /* A code-block data can be empty. In that case initialize data
+             * with 0xffff. */
+            if (cblk->lengthinc > 0)
+                bytestream_get_buffer(&s->buf, cblk->data, cblk->lengthinc);
+            else {
+                cblk->data[0] = 0xff;
+                cblk->data[1] = 0xff;
+            }
             cblk->length   += cblk->lengthinc;
             cblk->lengthinc = 0;
         }
@@ -853,12 +857,15 @@ static int decode_cblk(Jpeg2000DecoderContext *s, Jpeg2000CodingStyle *codsty,
 {
     int passno = cblk->npasses, pass_t = 2, bpno = cblk->nonzerobits - 1, y;

-    for (y = 0; y < height + 2; y++)
-        memset(t1->flags[y], 0, (width + 2) * sizeof(width));
-
     for (y = 0; y < height; y++)
         memset(t1->data[y], 0, width * sizeof(width));

+    /* If code-block contains no compressed data: nothing to do. */
+    if (cblk->length == 0)
+        return 0;
+    for (y = 0; y < height + 2; y++)
+        memset(t1->flags[y], 0, (width + 2) * sizeof(width));
+
     ff_mqc_initdec(&t1->mqc, cblk->data);
     cblk->data[cblk->length]     = 0xff;
     cblk->data[cblk->length + 1] = 0xff;
@@ -1252,8 +1259,6 @@ static int jpeg2000_decode_frame(AVCodecContext *avctx, void *data,
     s->buf_end   = s->buf_start + avpkt->size;
     s->curtileno = 0; // TODO: only one tile in DCI JP2K. to implement for more tiles

-    // reduction factor, i.e number of resolution levels to skip
-    s->reduction_factor = s->lowres;

     ff_jpeg2000_init_tier1_luts();

@@ -1301,12 +1306,6 @@ static int jpeg2000_decode_frame(AVCodecContext *avctx, void *data,
 #define OFFSET(x) offsetof(Jpeg2000DecoderContext, x)
 #define VD AV_OPT_FLAG_VIDEO_PARAM | AV_OPT_FLAG_DECODING_PARAM

-static const AVOption options[] = {
-    { "lowres",  "Lower the decoding resolution by a power of two",
-        OFFSET(lowres), AV_OPT_TYPE_INT, { .i64 = 0 }, 0, JPEG2000_MAX_RESLEVELS - 1, VD },
-    { NULL },
-};
-
 static const AVProfile profiles[] = {
     { FF_PROFILE_JPEG2000_CSTREAM_RESTRICTION_0,  "JPEG 2000 codestream restriction 0"   },
     { FF_PROFILE_JPEG2000_CSTREAM_RESTRICTION_1,  "JPEG 2000 codestream restriction 1"   },
@@ -1319,7 +1318,6 @@ static const AVProfile profiles[] = {
 static const AVClass class = {
     .class_name = "jpeg2000",
     .item_name  = av_default_item_name,
-    .option     = options,
     .version    = LIBAVUTIL_VERSION_INT,
 };

@@ -1330,6 +1328,7 @@ AVCodec ff_jpeg2000_decoder = {
     .id             = AV_CODEC_ID_JPEG2000,
     .capabilities   = CODEC_CAP_FRAME_THREADS,
     .priv_data_size = sizeof(Jpeg2000DecoderContext),
+    .max_lowres     = 31,
     .decode         = jpeg2000_decode_frame,
     .priv_class     = &class,
     .pix_fmts       = (enum PixelFormat[]) { AV_PIX_FMT_XYZ12,