lavc: change all decoders to behave consistently with AV_EF_CRCCHECK.

Just crccheck prints a warning, crccheck+explode returns an error.

Also document this behavior.

libavcodec/ac3dec.c

@@ -1330,6 +1330,8 @@ static int ac3_decode_frame(AVCodecContext * avctx, void *data,
             if (av_crc(av_crc_get_table(AV_CRC_16_ANSI), 0, &buf[2],
                        s->frame_size - 2)) {
                 av_log(avctx, AV_LOG_ERROR, "frame CRC mismatch\n");
+                if (avctx->err_recognition & AV_EF_EXPLODE)
+                    return AVERROR_INVALIDDATA;
                 err = AAC_AC3_PARSE_ERROR_CRC;
             }
         }

libavcodec/alsdec.c

@@ -1545,6 +1545,8 @@ static int decode_frame(AVCodecContext *avctx, void *data, int *got_frame_ptr,
         if (ctx->cur_frame_length != sconf->frame_length &&
             ctx->crc_org != ctx->crc) {
             av_log(avctx, AV_LOG_ERROR, "CRC error.\n");
+            if (avctx->err_recognition & AV_EF_EXPLODE)
+                return AVERROR_INVALIDDATA;
         }
     }
 

libavcodec/avcodec.h

@@ -2332,6 +2332,13 @@ typedef struct AVCodecContext {
      * - decoding: Set by user.
      */
     int err_recognition;
+
+/**
+ * Verify checksums embedded in the bitstream (could be of either encoded or
+ * decoded data, depending on the codec) and print an error message on mismatch.
+ * If AV_EF_EXPLODE is also set, a mismatching checksum will result in the
+ * decoder returning an error.
+ */
 #define AV_EF_CRCCHECK  (1<<0)
 #define AV_EF_BITSTREAM (1<<1)
 #define AV_EF_BUFFER    (1<<2)

libavcodec/takdec.c

@@ -693,6 +693,7 @@ static int tak_decode_frame(AVCodecContext *avctx, void *data,
     if (avctx->err_recognition & AV_EF_CRCCHECK) {
         if (ff_tak_check_crc(pkt->data, hsize)) {
             av_log(avctx, AV_LOG_ERROR, "CRC error\n");
+            if (avctx->err_recognition & AV_EF_EXPLODE)
                 return AVERROR_INVALIDDATA;
         }
     }
@@ -867,6 +868,7 @@ static int tak_decode_frame(AVCodecContext *avctx, void *data,
         if (ff_tak_check_crc(pkt->data + hsize,
                              get_bits_count(gb) / 8 - hsize)) {
             av_log(avctx, AV_LOG_ERROR, "CRC error\n");
+            if (avctx->err_recognition & AV_EF_EXPLODE)
                 return AVERROR_INVALIDDATA;
         }
     }

libavcodec/tta.c

@@ -275,7 +275,8 @@ static av_cold int tta_decode_init(AVCodecContext * avctx)
             avctx->extradata_size - 26 < total_frames * 4)
             av_log(avctx, AV_LOG_WARNING, "Seek table missing or too small\n");
         else if (avctx->err_recognition & AV_EF_CRCCHECK) {
-            if (tta_check_crc(s, avctx->extradata + 22, total_frames * 4))
+            int ret = tta_check_crc(s, avctx->extradata + 22, total_frames * 4);
+            if (ret < 0 && avctx->err_recognition & AV_EF_EXPLODE)
                 return AVERROR_INVALIDDATA;
         }
         skip_bits_long(&s->gb, 32 * total_frames);
@@ -316,7 +317,8 @@ static int tta_decode_frame(AVCodecContext *avctx, void *data,
     int32_t *p;
 
     if (avctx->err_recognition & AV_EF_CRCCHECK) {
-        if (buf_size < 4 || tta_check_crc(s, buf, buf_size - 4))
+        if (buf_size < 4 ||
+            (tta_check_crc(s, buf, buf_size - 4) && avctx->err_recognition & AV_EF_EXPLODE))
             return AVERROR_INVALIDDATA;
     }
 

libavcodec/wavpack.c

@@ -699,9 +699,11 @@ static inline int wv_unpack_mono(WavpackFrameContext *s, GetBitContext *gb,
     } while (!last && count < s->samples);
 
     wv_reset_saved_context(s);
-    if ((s->avctx->err_recognition & AV_EF_CRCCHECK) &&
-        wv_check_crc(s, crc, crc_extra_bits))
-        return AVERROR_INVALIDDATA;
+    if (s->avctx->err_recognition & AV_EF_CRCCHECK) {
+        int ret = wv_check_crc(s, crc, crc_extra_bits);
+        if (ret < 0 && s->avctx->err_recognition & AV_EF_EXPLODE)
+            return ret;
+    }
 
     return 0;
 }