dfpw: convert to new channel layout API

libavcodec/dfpwmdec.c

@@ -83,7 +83,7 @@ static av_cold int dfpwm_dec_init(struct AVCodecContext *ctx)
 {
     DFPWMState *state = ctx->priv_data;
 
-    if (ctx->channels <= 0) {
+    if (ctx->ch_layout.nb_channels <= 0) {
         av_log(ctx, AV_LOG_ERROR, "Invalid number of channels\n");
         return AVERROR(EINVAL);
     }
@@ -106,7 +106,7 @@ static int dfpwm_dec_frame(struct AVCodecContext *ctx, void *data,
     AVFrame *frame = data;
     int ret;
 
-    frame->nb_samples = packet->size * 8 / ctx->channels;
+    frame->nb_samples = packet->size * 8 / ctx->ch_layout.nb_channels;
     if (frame->nb_samples <= 0) {
         av_log(ctx, AV_LOG_ERROR, "invalid number of samples in packet\n");
         return AVERROR_INVALIDDATA;

libavcodec/dfpwmenc.c

@@ -93,7 +93,7 @@ static int dfpwm_enc_frame(struct AVCodecContext *ctx, struct AVPacket *packet,
     const struct AVFrame *frame, int *got_packet)
 {
     DFPWMState *state = ctx->priv_data;
-    int size = frame->nb_samples * frame->channels / 8 + (frame->nb_samples % 8 > 0 ? 1 : 0);
+    int size = frame->nb_samples * frame->ch_layout.nb_channels / 8 + (frame->nb_samples % 8 > 0 ? 1 : 0);
     int ret = ff_get_encode_buffer(ctx, packet, size, 0);
 
     if (ret) {