@@ -51,7 +51,7 @@ static uint32_t codec_flags(enum AVCodecID codec_id) {

     }

 }

-static uint32_t samples_per_packet(enum AVCodecID codec_id, int channels) {

+static uint32_t samples_per_packet(enum AVCodecID codec_id, int channels, int block_align) {

     switch (codec_id) {

     case AV_CODEC_ID_PCM_S8:

     case AV_CODEC_ID_PCM_S16LE:

@@ -91,9 +91,9 @@ static uint32_t samples_per_packet(enum AVCodecID codec_id, int channels) {

     case AV_CODEC_ID_ALAC:

         return 4096;

     case AV_CODEC_ID_ADPCM_IMA_WAV:

-        return (1024 - 4 * channels) * 8 / (4 * channels) + 1;

+        return (block_align - 4 * channels) * 8 / (4 * channels) + 1;

     case AV_CODEC_ID_ADPCM_MS:

-        return (1024 - 7 * channels) * 2 / channels + 2;

+        return (block_align - 7 * channels) * 2 / channels + 2;

     default:

         return 0;

     }

@@ -146,7 +146,7 @@ static int caf_write_header(AVFormatContext *s)

     }

     if (enc->codec_id != AV_CODEC_ID_MP3 || frame_size != 576)

-        frame_size = samples_per_packet(enc->codec_id, enc->channels);

+        frame_size = samples_per_packet(enc->codec_id, enc->channels, enc->block_align);

     ffio_wfourcc(pb, "caff"); //< mFileType

     avio_wb16(pb, 1);         //< mFileVersion

@@ -259,7 +259,7 @@ static int caf_write_trailer(AVFormatContext *s)

             ffio_wfourcc(pb, "pakt");

             avio_wb64(pb, caf->size_entries_used + 24);

             avio_wb64(pb, caf->packets); ///< mNumberPackets

-            avio_wb64(pb, caf->packets * samples_per_packet(enc->codec_id, enc->channels)); ///< mNumberValidFrames

+            avio_wb64(pb, caf->packets * samples_per_packet(enc->codec_id, enc->channels, enc->block_align)); ///< mNumberValidFrames

             avio_wb32(pb, 0); ///< mPrimingFrames

             avio_wb32(pb, 0); ///< mRemainderFrames

             avio_write(pb, caf->pkt_sizes, caf->size_entries_used);