lavc/flacenc: improve error return.

Use meaningful error codes and add log messages.

libavcodec/flacenc.c

@@ -248,8 +248,11 @@ static av_cold int flac_encode_init(AVCodecContext *avctx)
         break;
     }
 
-    if (channels < 1 || channels > FLAC_MAX_CHANNELS)
-        return -1;
+    if (channels < 1 || channels > FLAC_MAX_CHANNELS) {
+        av_log(avctx, AV_LOG_ERROR, "%d channels not supported (max %d)\n",
+               channels, FLAC_MAX_CHANNELS);
+        return AVERROR(EINVAL);
+    }
     s->channels = channels;
 
     /* find samplerate in table */
@@ -275,7 +278,8 @@ static av_cold int flac_encode_init(AVCodecContext *avctx)
             s->sr_code[0] = 13;
             s->sr_code[1] = freq;
         } else {
-            return -1;
+            av_log(avctx, AV_LOG_ERROR, "%d Hz not supported\n", freq);
+            return AVERROR(EINVAL);
         }
         s->samplerate = freq;
     }
@@ -290,7 +294,7 @@ static av_cold int flac_encode_init(AVCodecContext *avctx)
     if (level > 12) {
         av_log(avctx, AV_LOG_ERROR, "invalid compression level: %d\n",
                s->options.compression_level);
-        return -1;
+        return AVERROR(EINVAL);
     }
 
     s->options.block_time_ms = ((int[]){ 27, 27, 27,105,105,105,105,105,105,105,105,105,105})[level];
@@ -329,13 +333,13 @@ static av_cold int flac_encode_init(AVCodecContext *avctx)
             if (avctx->min_prediction_order > MAX_FIXED_ORDER) {
                 av_log(avctx, AV_LOG_ERROR, "invalid min prediction order: %d\n",
                        avctx->min_prediction_order);
-                return -1;
+                return AVERROR(EINVAL);
             }
         } else if (avctx->min_prediction_order < MIN_LPC_ORDER ||
                    avctx->min_prediction_order > MAX_LPC_ORDER) {
             av_log(avctx, AV_LOG_ERROR, "invalid min prediction order: %d\n",
                    avctx->min_prediction_order);
-            return -1;
+            return AVERROR(EINVAL);
         }
         s->options.min_prediction_order = avctx->min_prediction_order;
     }
@@ -346,20 +350,20 @@ static av_cold int flac_encode_init(AVCodecContext *avctx)
             if (avctx->max_prediction_order > MAX_FIXED_ORDER) {
                 av_log(avctx, AV_LOG_ERROR, "invalid max prediction order: %d\n",
                        avctx->max_prediction_order);
-                return -1;
+                return AVERROR(EINVAL);
             }
         } else if (avctx->max_prediction_order < MIN_LPC_ORDER ||
                    avctx->max_prediction_order > MAX_LPC_ORDER) {
             av_log(avctx, AV_LOG_ERROR, "invalid max prediction order: %d\n",
                    avctx->max_prediction_order);
-            return -1;
+            return AVERROR(EINVAL);
         }
         s->options.max_prediction_order = avctx->max_prediction_order;
     }
     if (s->options.max_prediction_order < s->options.min_prediction_order) {
         av_log(avctx, AV_LOG_ERROR, "invalid prediction orders: min=%d max=%d\n",
                s->options.min_prediction_order, s->options.max_prediction_order);
-        return -1;
+        return AVERROR(EINVAL);
     }
 
     if (avctx->frame_size > 0) {
@@ -367,7 +371,7 @@ static av_cold int flac_encode_init(AVCodecContext *avctx)
                 avctx->frame_size > FLAC_MAX_BLOCKSIZE) {
             av_log(avctx, AV_LOG_ERROR, "invalid block size: %d\n",
                    avctx->frame_size);
-            return -1;
+            return AVERROR(EINVAL);
         }
     } else {
         s->avctx->frame_size = select_blocksize(s->samplerate, s->options.block_time_ms);