diff --git a/libavformat/isom.h b/libavformat/isom.h
index eb942cf882..4245d37767 100644
--- a/libavformat/isom.h
+++ b/libavformat/isom.h
@@ -224,16 +224,6 @@ typedef struct MOVStreamContext {
 
     int has_sidx;  // If there is an sidx entry for this stream.
     struct {
-        // TODO: Remove once old methods are removed from mov.c
-        int use_subsamples;
-        uint8_t* auxiliary_info;
-        uint8_t* auxiliary_info_end;
-        uint8_t* auxiliary_info_pos;
-        uint8_t auxiliary_info_default_size;
-        uint8_t* auxiliary_info_sizes;
-        size_t auxiliary_info_sizes_count;
-        int64_t auxiliary_info_index;
-
         struct AVAESCTR* aes_ctr;
         unsigned int per_sample_iv_size;  // Either 0, 8, or 16.
         AVEncryptionInfo *default_encrypted_sample;
diff --git a/libavformat/mov.c b/libavformat/mov.c
index 4eda48d617..45d8e1dce7 100644
--- a/libavformat/mov.c
+++ b/libavformat/mov.c
@@ -6009,67 +6009,6 @@ static int mov_read_tenc(MOVContext *c, AVIOContext *pb, MOVAtom atom)
     return 0;
 }
 
-static int mov_read_saiz(MOVContext *c, AVIOContext *pb, MOVAtom atom)
-{
-    AVStream *st;
-    MOVStreamContext *sc;
-    size_t data_size;
-    int atom_header_size;
-    int flags;
-
-    if (c->decryption_key_len == 0 || c->fc->nb_streams < 1)
-        return 0;
-
-    st = c->fc->streams[c->fc->nb_streams - 1];
-    sc = st->priv_data;
-
-    if (sc->cenc.auxiliary_info_sizes || sc->cenc.auxiliary_info_default_size) {
-        av_log(c->fc, AV_LOG_ERROR, "duplicate saiz atom\n");
-        return AVERROR_INVALIDDATA;
-    }
-
-    atom_header_size = 9;
-
-    avio_r8(pb); /* version */
-    flags = avio_rb24(pb);
-
-    if ((flags & 0x01) != 0) {
-        atom_header_size += 8;
-
-        avio_rb32(pb);    /* info type */
-        avio_rb32(pb);    /* info type param */
-    }
-
-    sc->cenc.auxiliary_info_default_size = avio_r8(pb);
-    avio_rb32(pb);    /* entries */
-
-    if (atom.size <= atom_header_size) {
-        return 0;
-    }
-
-    if (atom.size > FFMIN(INT_MAX, SIZE_MAX)) {
-        av_log(c->fc, AV_LOG_ERROR, "saiz atom auxiliary_info_sizes size %"PRId64" invalid\n", atom.size);
-        return AVERROR_INVALIDDATA;
-    }
-
-    /* save the auxiliary info sizes as is */
-    data_size = atom.size - atom_header_size;
-
-    sc->cenc.auxiliary_info_sizes = av_malloc(data_size);
-    if (!sc->cenc.auxiliary_info_sizes) {
-        return AVERROR(ENOMEM);
-    }
-
-    sc->cenc.auxiliary_info_sizes_count = data_size;
-
-    if (avio_read(pb, sc->cenc.auxiliary_info_sizes, data_size) != data_size) {
-        av_log(c->fc, AV_LOG_ERROR, "failed to read the auxiliary info sizes");
-        return AVERROR_INVALIDDATA;
-    }
-
-    return 0;
-}
-
 static int mov_read_dfla(MOVContext *c, AVIOContext *pb, MOVAtom atom)
 {
     AVStream *st;
@@ -6107,36 +6046,6 @@ static int mov_read_dfla(MOVContext *c, AVIOContext *pb, MOVAtom atom)
     return 0;
 }
 
-static int mov_seek_auxiliary_info(MOVContext *c, MOVStreamContext *sc, int64_t index)
-{
-    size_t auxiliary_info_seek_offset = 0;
-    int i;
-
-    if (sc->cenc.auxiliary_info_default_size) {
-        auxiliary_info_seek_offset = (size_t)sc->cenc.auxiliary_info_default_size * index;
-    } else if (sc->cenc.auxiliary_info_sizes) {
-        if (index > sc->cenc.auxiliary_info_sizes_count) {
-            av_log(c, AV_LOG_ERROR, "current sample %"PRId64" greater than the number of auxiliary info sample sizes %"SIZE_SPECIFIER"\n",
-                index, sc->cenc.auxiliary_info_sizes_count);
-            return AVERROR_INVALIDDATA;
-        }
-
-        for (i = 0; i < index; i++) {
-            auxiliary_info_seek_offset += sc->cenc.auxiliary_info_sizes[i];
-        }
-    }
-
-    if (auxiliary_info_seek_offset > sc->cenc.auxiliary_info_end - sc->cenc.auxiliary_info) {
-        av_log(c, AV_LOG_ERROR, "auxiliary info offset %"SIZE_SPECIFIER" greater than auxiliary info size %"SIZE_SPECIFIER"\n",
-            auxiliary_info_seek_offset, (size_t)(sc->cenc.auxiliary_info_end - sc->cenc.auxiliary_info));
-        return AVERROR_INVALIDDATA;
-    }
-
-    sc->cenc.auxiliary_info_pos = sc->cenc.auxiliary_info + auxiliary_info_seek_offset;
-    sc->cenc.auxiliary_info_index = index;
-    return 0;
-}
-
 static int cenc_decrypt(MOVContext *c, MOVStreamContext *sc, AVEncryptionInfo *sample, uint8_t *input, int size)
 {
     int i, ret;