libavcodec/libopenjpegenc: enable lossless option, remove layer option, and improve defaults

1. limit to single layer, as there is no current support for setting distortion/quality of multiple layers
2. encoder mode should be kept at default setting (0)
3. remove fixed_alloc parameter from context : seldom if ever used, and no way of properly configuring at the moment
4. add irreversible setting, to allow for lossless encoding. Set to OpenJPEG default (enabled)
5. set numresolution max to 33, which is the maximum number of allowed resolutions according the J2K spec
Signed-off-by: Michael Bradshaw <mjbshaw@google.com>

libavcodec/libopenjpegenc.c

@@ -64,9 +64,8 @@ typedef struct LibOpenJPEGContext {
     int prog_order;
     int cinema_mode;
     int numresolution;
-    int numlayers;
+    int irreversible;
     int disto_alloc;
-    int fixed_alloc;
     int fixed_quality;
 } LibOpenJPEGContext;
 
@@ -358,13 +357,12 @@ static av_cold int libopenjpeg_encode_init(AVCodecContext *avctx)
             ctx->numresolution --;
     }
 
-    ctx->enc_params.mode = !!avctx->global_quality;
     ctx->enc_params.prog_order = ctx->prog_order;
     ctx->enc_params.numresolution = ctx->numresolution;
+    ctx->enc_params.irreversible = ctx->irreversible;
     ctx->enc_params.cp_disto_alloc = ctx->disto_alloc;
-    ctx->enc_params.cp_fixed_alloc = ctx->fixed_alloc;
     ctx->enc_params.cp_fixed_quality = ctx->fixed_quality;
-    ctx->enc_params.tcp_numlayers = ctx->numlayers;
+    ctx->enc_params.tcp_numlayers = 1;
     ctx->enc_params.tcp_rates[0] = FFMAX(avctx->compression_level, 0) * 2;
 
     if (ctx->cinema_mode > 0) {
@@ -838,11 +836,10 @@ static const AVOption options[] = {
     { "rpcl",          NULL,                0,                     AV_OPT_TYPE_CONST, { .i64 = OPJ(RPCL)    }, 0,         0,           VE, "prog_order"  },
     { "pcrl",          NULL,                0,                     AV_OPT_TYPE_CONST, { .i64 = OPJ(PCRL)    }, 0,         0,           VE, "prog_order"  },
     { "cprl",          NULL,                0,                     AV_OPT_TYPE_CONST, { .i64 = OPJ(CPRL)    }, 0,         0,           VE, "prog_order"  },
-    { "numresolution", NULL,                OFFSET(numresolution), AV_OPT_TYPE_INT,   { .i64 = 0           }, 0,         INT_MAX,     VE                },
-    { "numlayers",     NULL,                OFFSET(numlayers),     AV_OPT_TYPE_INT,   { .i64 = 1           }, 1,         10,          VE                },
-    { "disto_alloc",   NULL,                OFFSET(disto_alloc),   AV_OPT_TYPE_INT,   { .i64 = 1           }, 0,         1,           VE                },
-    { "fixed_alloc",   NULL,                OFFSET(fixed_alloc),   AV_OPT_TYPE_INT,   { .i64 = 0           }, 0,         1,           VE                },
-    { "fixed_quality", NULL,                OFFSET(fixed_quality), AV_OPT_TYPE_INT,   { .i64 = 0           }, 0,         1,           VE                },
+    { "numresolution", NULL,                OFFSET(numresolution), AV_OPT_TYPE_INT,   { .i64 = 6            }, 0,         33,          VE                },
+    { "irreversible",  NULL,                OFFSET(irreversible),  AV_OPT_TYPE_INT,   { .i64 = 0            }, 0,         1,           VE                },
+    { "disto_alloc",   NULL,                OFFSET(disto_alloc),   AV_OPT_TYPE_INT,   { .i64 = 1            }, 0,         1,           VE                },
+    { "fixed_quality", NULL,                OFFSET(fixed_quality), AV_OPT_TYPE_INT,   { .i64 = 0            }, 0,         1,           VE                },
     { NULL },
 };