avcodec/adpcm: Check block align for AV_CODEC_ID_ADPCM_PSX

Regression since: ca49476ace
Fixes: out of array write
Fixes: 25786/clusterfuzz-testcase-minimized-ffmpeg_AV_CODEC_ID_ADPCM_PSX_fuzzer-5704869380620288

Found-by: continuous fuzzing process https://github.com/google/oss-fuzz/tree/master/projects/ffmpeg
Signed-off-by: Michael Niedermayer <michael@niedermayer.cc>

libavcodec/adpcm.c

@@ -135,6 +135,8 @@ static av_cold int adpcm_decode_init(AVCodecContext * avctx)
         break;
     case AV_CODEC_ID_ADPCM_PSX:
         max_channels = 8;
+        if (avctx->block_align % (16 * avctx->channels))
+            return AVERROR_INVALIDDATA;
         break;
     case AV_CODEC_ID_ADPCM_IMA_DAT4:
     case AV_CODEC_ID_ADPCM_THP:
@@ -1968,6 +1970,7 @@ static int adpcm_decode_frame(AVCodecContext *avctx, void *data,
             int nb_samples_per_block = 28 * FFMAX(avctx->block_align, 16 * avctx->channels) / (16 * avctx->channels);
             for (channel = 0; channel < avctx->channels; channel++) {
                 samples = samples_p[channel] + block * nb_samples_per_block;
+                av_assert0((block + 1) * nb_samples_per_block <= nb_samples);
 
                 /* Read in every sample for this channel.  */
                 for (i = 0; i < nb_samples_per_block / 28; i++) {