libavcodec/hapdec : add support HapAlphaOnly

Signed-off-by: Michael Niedermayer <michael@niedermayer.cc>

libavcodec/hap.h

@@ -34,6 +34,7 @@ enum HapTextureFormat {
     HAP_FMT_RGBDXT1   = 0x0B,
     HAP_FMT_RGBADXT5  = 0x0E,
     HAP_FMT_YCOCGDXT5 = 0x0F,
+    HAP_FMT_RGTC1     = 0x01,
 };
 
 enum HapCompressor {

libavcodec/hapdec.c

@@ -24,7 +24,7 @@
  * @file
  * Hap decoder
  *
- * Fourcc: Hap1, Hap5, HapY
+ * Fourcc: Hap1, Hap5, HapY, HapA, HapM
  *
  * https://github.com/Vidvox/hap/blob/master/documentation/HapVideoDRAFT.md
  */
@@ -163,7 +163,8 @@ static int hap_parse_frame_header(AVCodecContext *avctx)
 
     if ((avctx->codec_tag == MKTAG('H','a','p','1') && (section_type & 0x0F) != HAP_FMT_RGBDXT1) ||
         (avctx->codec_tag == MKTAG('H','a','p','5') && (section_type & 0x0F) != HAP_FMT_RGBADXT5) ||
-        (avctx->codec_tag == MKTAG('H','a','p','Y') && (section_type & 0x0F) != HAP_FMT_YCOCGDXT5)) {
+        (avctx->codec_tag == MKTAG('H','a','p','Y') && (section_type & 0x0F) != HAP_FMT_YCOCGDXT5) ||
+        (avctx->codec_tag == MKTAG('H','a','p','A') && (section_type & 0x0F) != HAP_FMT_RGTC1)) {
         av_log(avctx, AV_LOG_ERROR,
                "Invalid texture format %#04x.\n", section_type & 0x0F);
         return AVERROR_INVALIDDATA;
@@ -403,6 +404,15 @@ static av_cold int hap_init(AVCodecContext *avctx)
         ctx->tex_fun = ctx->dxtc.dxt5ys_block;
         avctx->pix_fmt = AV_PIX_FMT_RGB0;
         break;
+    case MKTAG('H','a','p','A'):
+        texture_name = "RGTC1";
+        ctx->tex_rat = 8;
+        ctx->tex_fun = ctx->dxtc.rgtc1u_block;
+        avctx->pix_fmt = AV_PIX_FMT_RGB0;
+        break;
+    case MKTAG('H','a','p','M'):
+        avpriv_report_missing_feature(avctx, "HapQAlpha");
+        return AVERROR_PATCHWELCOME;
     default:
         return AVERROR_DECODER_NOT_FOUND;
     }