diff --git a/libavcodec/adpcmenc.c b/libavcodec/adpcmenc.c
index 6295eedc55..2a117f4aae 100644
--- a/libavcodec/adpcmenc.c
+++ b/libavcodec/adpcmenc.c
@@ -86,6 +86,8 @@ static av_cold int adpcm_encode_init(AVCodecContext *avctx)
         FF_ALLOC_OR_GOTO(avctx, s->trellis_hash, 65536 * sizeof(*s->trellis_hash), error);
     }
 
+    avctx->bits_per_coded_sample = av_get_bits_per_sample(avctx->codec->id);
+
     switch(avctx->codec->id) {
     case CODEC_ID_ADPCM_IMA_WAV:
         avctx->frame_size = (BLKSIZE - 4 * avctx->channels) * 8 / (4 * avctx->channels) + 1; /* each 16 bits sample gives one nibble */
diff --git a/libavcodec/utils.c b/libavcodec/utils.c
index 9f198cb32a..8459e5f870 100644
--- a/libavcodec/utils.c
+++ b/libavcodec/utils.c
@@ -1121,6 +1121,8 @@ int av_get_bits_per_sample(enum CodecID codec_id){
     case CODEC_ID_ADPCM_SBPRO_4:
     case CODEC_ID_ADPCM_CT:
     case CODEC_ID_ADPCM_IMA_WAV:
+    case CODEC_ID_ADPCM_IMA_QT:
+    case CODEC_ID_ADPCM_SWF:
     case CODEC_ID_ADPCM_MS:
     case CODEC_ID_ADPCM_YAMAHA:
         return 4;