[FFmpeg-devel] [RFC] cryptokey options

[Reimar Döffinger]

Hello,
I tried to implement this via a generic "binary" option type, but it
does not seem to work, avfc->key stays NULL in the demuxer.
Maybe that is just because I don't know how to use ffmpeg though...
Fixes welcome.

Greetings,
Reimar D?ffinger
-------------- next part --------------
diff --git a/libavcodec/opt.c b/libavcodec/opt.c
index deddfd1..df845e8 100644
--- a/libavcodec/opt.c
+++ b/libavcodec/opt.c
@@ -107,6 +107,13 @@ static const char *const_names[]={
     0
 };
 
+static int hexchar2int(char c) {
+    if (c >= '0' && c <= '9') return c - '0';
+    if (c >= 'a' && c <= 'f') return c - 'a' + 10;
+    if (c >= 'A' && c <= 'F') return c - 'A' + 10;
+    return -1;
+}
+
 const AVOption *av_set_string(void *obj, const char *name, const char *val){
     const AVOption *o= av_find_opt(obj, name, NULL, 0, 0);
     if(o && o->offset==0 && o->type == FF_OPT_TYPE_CONST && o->unit){
@@ -114,6 +121,25 @@ const AVOption *av_set_string(void *obj, const char *name, const char *val){
     }
     if(!o || !val || o->offset<=0)
         return NULL;
+    if(o->type == FF_OPT_TYPE_BINARY){
+        uint8_t *bin;
+        int len = strlen(val);
+        if (len & 1) return NULL;
+        len /= 2;
+        bin = av_malloc(len);
+        while (*val) {
+            int a = hexchar2int(*val++);
+            int b = hexchar2int(*val++);
+            if (a < 0 || b < 0) {
+                av_free(bin);
+                return NULL;
+            }
+            *bin++ = (a << 4) | b;
+        }
+        memcpy(((uint8_t*)obj) + o->offset , &bin, sizeof(bin));
+        memcpy(((uint8_t*)obj) + o->offset2, &len, sizeof(len));
+        return o;
+    }
     if(o->type != FF_OPT_TYPE_STRING){
         for(;;){
             int i;
@@ -307,6 +333,9 @@ static void opt_list(void *obj, void *av_log_obj, const char *unit)
             case FF_OPT_TYPE_RATIONAL:
                 av_log( av_log_obj, AV_LOG_INFO, "%-7s ", "<rational>" );
                 break;
+            case FF_OPT_TYPE_BINARY:
+                av_log( av_log_obj, AV_LOG_INFO, "%-7s ", "<binary>" );
+                break;
             case FF_OPT_TYPE_CONST:
             default:
                 av_log( av_log_obj, AV_LOG_INFO, "%-7s ", "" );
@@ -374,6 +403,7 @@ void av_opt_set_defaults2(void *s, int mask, int flags)
             }
             break;
             case FF_OPT_TYPE_STRING:
+            case FF_OPT_TYPE_BINARY:
                 /* Cannot set default for string as default_val is of type * double */
             break;
             default:
diff --git a/libavcodec/opt.h b/libavcodec/opt.h
index 0860d16..7e25a69 100644
--- a/libavcodec/opt.h
+++ b/libavcodec/opt.h
@@ -37,6 +37,7 @@ enum AVOptionType{
     FF_OPT_TYPE_FLOAT,
     FF_OPT_TYPE_STRING,
     FF_OPT_TYPE_RATIONAL,
+    FF_OPT_TYPE_BINARY,
     FF_OPT_TYPE_CONST=128,
 };
 
@@ -67,6 +68,7 @@ typedef struct AVOption {
 #define AV_OPT_FLAG_SUBTITLE_PARAM  32
 //FIXME think about enc-audio, ... style flags
     const char *unit;
+    int offset2;
 } AVOption;
 
 
diff --git a/libavformat/utils.c b/libavformat/utils.c
index cb03c89..29856b4 100644
--- a/libavformat/utils.c
+++ b/libavformat/utils.c
@@ -311,6 +311,7 @@ static const AVOption options[]={
 {"track", " set the track number", OFFSET(track), FF_OPT_TYPE_INT, DEFAULT, 0, INT_MAX, E},
 {"year", "set the year", OFFSET(year), FF_OPT_TYPE_INT, DEFAULT, INT_MIN, INT_MAX, E},
 {"analyzeduration", "how many microseconds are analyzed to estimate duration", OFFSET(max_analyze_duration), FF_OPT_TYPE_INT, 3*AV_TIME_BASE, 0, INT_MAX, D},
+{"cryptokey", "decryption key", OFFSET(key), FF_OPT_TYPE_BINARY, 0, 0, 0, D, NULL, OFFSET(keylen)},
 {NULL},
 };