diff --git a/libavcodec/pngenc.c b/libavcodec/pngenc.c
index 946b816f0f..c036fcb1ec 100644
--- a/libavcodec/pngenc.c
+++ b/libavcodec/pngenc.c
@@ -48,6 +48,11 @@ typedef struct PNGEncContext {
     uint8_t buf[IOBUF_SIZE];
     int dpi;                     ///< Physical pixel density, in dots per inch, if set
     int dpm;                     ///< Physical pixel density, in dots per meter, if set
+
+    int is_progressive;
+    int bit_depth;
+    int color_type;
+    int bits_per_pixel;
 } PNGEncContext;
 
 static void png_get_interlaced_row(uint8_t *dst, int row_size,
@@ -291,8 +296,8 @@ static int encode_frame(AVCodecContext *avctx, AVPacket *pkt,
 {
     PNGEncContext *s       = avctx->priv_data;
     const AVFrame *const p = pict;
-    int bit_depth, color_type, y, len, row_size, ret, is_progressive;
-    int bits_per_pixel, pass_row_size, enc_row_size;
+    int y, len, row_size, ret;
+    int pass_row_size, enc_row_size;
     int64_t max_packet_size;
     int compression_level;
     uint8_t *ptr, *top, *crow_buf, *crow;
@@ -300,53 +305,7 @@ static int encode_frame(AVCodecContext *avctx, AVPacket *pkt,
     uint8_t *progressive_buf = NULL;
     uint8_t *top_buf         = NULL;
 
-    is_progressive = !!(avctx->flags & CODEC_FLAG_INTERLACED_DCT);
-    switch (avctx->pix_fmt) {
-    case AV_PIX_FMT_RGBA64BE:
-        bit_depth = 16;
-        color_type = PNG_COLOR_TYPE_RGB_ALPHA;
-        break;
-    case AV_PIX_FMT_RGB48BE:
-        bit_depth = 16;
-        color_type = PNG_COLOR_TYPE_RGB;
-        break;
-    case AV_PIX_FMT_RGBA:
-        bit_depth  = 8;
-        color_type = PNG_COLOR_TYPE_RGB_ALPHA;
-        break;
-    case AV_PIX_FMT_RGB24:
-        bit_depth  = 8;
-        color_type = PNG_COLOR_TYPE_RGB;
-        break;
-    case AV_PIX_FMT_GRAY16BE:
-        bit_depth  = 16;
-        color_type = PNG_COLOR_TYPE_GRAY;
-        break;
-    case AV_PIX_FMT_GRAY8:
-        bit_depth  = 8;
-        color_type = PNG_COLOR_TYPE_GRAY;
-        break;
-    case AV_PIX_FMT_GRAY8A:
-        bit_depth = 8;
-        color_type = PNG_COLOR_TYPE_GRAY_ALPHA;
-        break;
-    case AV_PIX_FMT_YA16BE:
-        bit_depth = 16;
-        color_type = PNG_COLOR_TYPE_GRAY_ALPHA;
-        break;
-    case AV_PIX_FMT_MONOBLACK:
-        bit_depth  = 1;
-        color_type = PNG_COLOR_TYPE_GRAY;
-        break;
-    case AV_PIX_FMT_PAL8:
-        bit_depth  = 8;
-        color_type = PNG_COLOR_TYPE_PALETTE;
-        break;
-    default:
-        return -1;
-    }
-    bits_per_pixel = ff_png_get_nb_channels(color_type) * bit_depth;
-    row_size       = (avctx->width * bits_per_pixel + 7) >> 3;
+    row_size       = (avctx->width * s->bits_per_pixel + 7) >> 3;
 
     s->zstream.zalloc = ff_png_zalloc;
     s->zstream.zfree  = ff_png_zfree;
@@ -379,7 +338,7 @@ static int encode_frame(AVCodecContext *avctx, AVPacket *pkt,
     }
     // pixel data should be aligned, but there's a control byte before it
     crow_buf = crow_base + 15;
-    if (is_progressive) {
+    if (s->is_progressive) {
         progressive_buf = av_malloc(row_size + 1);
         top_buf = av_malloc(row_size + 1);
         if (!progressive_buf || !top_buf) {
@@ -394,11 +353,11 @@ static int encode_frame(AVCodecContext *avctx, AVPacket *pkt,
 
     AV_WB32(s->buf, avctx->width);
     AV_WB32(s->buf + 4, avctx->height);
-    s->buf[8]  = bit_depth;
-    s->buf[9]  = color_type;
+    s->buf[8]  = s->bit_depth;
+    s->buf[9]  = s->color_type;
     s->buf[10] = 0; /* compression type */
     s->buf[11] = 0; /* filter type */
-    s->buf[12] = is_progressive; /* interlace type */
+    s->buf[12] = s->is_progressive; /* interlace type */
     png_write_chunk(&s->bytestream, MKTAG('I', 'H', 'D', 'R'), s->buf, 13);
 
     /* write physical information */
@@ -426,7 +385,7 @@ static int encode_frame(AVCodecContext *avctx, AVPacket *pkt,
         png_write_chunk(&s->bytestream, MKTAG('g', 'A', 'M', 'A'), s->buf, 4);
 
     /* put the palette if needed */
-    if (color_type == PNG_COLOR_TYPE_PALETTE) {
+    if (s->color_type == PNG_COLOR_TYPE_PALETTE) {
         int has_alpha, alpha, i;
         unsigned int v;
         uint32_t *palette;
@@ -455,13 +414,13 @@ static int encode_frame(AVCodecContext *avctx, AVPacket *pkt,
     /* now put each row */
     s->zstream.avail_out = IOBUF_SIZE;
     s->zstream.next_out  = s->buf;
-    if (is_progressive) {
+    if (s->is_progressive) {
         int pass;
 
         for (pass = 0; pass < NB_PASSES; pass++) {
             /* NOTE: a pass is completely omitted if no pixels would be
              * output */
-            pass_row_size = ff_png_pass_row_size(pass, bits_per_pixel, avctx->width);
+            pass_row_size = ff_png_pass_row_size(pass, s->bits_per_pixel, avctx->width);
             if (pass_row_size > 0) {
                 top = NULL;
                 for (y = 0; y < avctx->height; y++)
@@ -469,10 +428,10 @@ static int encode_frame(AVCodecContext *avctx, AVPacket *pkt,
                         ptr = p->data[0] + y * p->linesize[0];
                         FFSWAP(uint8_t *, progressive_buf, top_buf);
                         png_get_interlaced_row(progressive_buf, pass_row_size,
-                                               bits_per_pixel, pass,
+                                               s->bits_per_pixel, pass,
                                                ptr, avctx->width);
                         crow = png_choose_filter(s, crow_buf, progressive_buf,
-                                                 top, pass_row_size, bits_per_pixel >> 3);
+                                                 top, pass_row_size, s->bits_per_pixel >> 3);
                         png_write_row(s, crow, pass_row_size + 1);
                         top = progressive_buf;
                     }
@@ -483,7 +442,7 @@ static int encode_frame(AVCodecContext *avctx, AVPacket *pkt,
         for (y = 0; y < avctx->height; y++) {
             ptr = p->data[0] + y * p->linesize[0];
             crow = png_choose_filter(s, crow_buf, ptr, top,
-                                     row_size, bits_per_pixel >> 3);
+                                     row_size, s->bits_per_pixel >> 3);
             png_write_row(s, crow, row_size + 1);
             top = ptr;
         }
@@ -563,6 +522,53 @@ static av_cold int png_enc_init(AVCodecContext *avctx)
       s->dpm = s->dpi * 10000 / 254;
     }
 
+    s->is_progressive = !!(avctx->flags & CODEC_FLAG_INTERLACED_DCT);
+    switch (avctx->pix_fmt) {
+    case AV_PIX_FMT_RGBA64BE:
+        s->bit_depth = 16;
+        s->color_type = PNG_COLOR_TYPE_RGB_ALPHA;
+        break;
+    case AV_PIX_FMT_RGB48BE:
+        s->bit_depth = 16;
+        s->color_type = PNG_COLOR_TYPE_RGB;
+        break;
+    case AV_PIX_FMT_RGBA:
+        s->bit_depth  = 8;
+        s->color_type = PNG_COLOR_TYPE_RGB_ALPHA;
+        break;
+    case AV_PIX_FMT_RGB24:
+        s->bit_depth  = 8;
+        s->color_type = PNG_COLOR_TYPE_RGB;
+        break;
+    case AV_PIX_FMT_GRAY16BE:
+        s->bit_depth  = 16;
+        s->color_type = PNG_COLOR_TYPE_GRAY;
+        break;
+    case AV_PIX_FMT_GRAY8:
+        s->bit_depth  = 8;
+        s->color_type = PNG_COLOR_TYPE_GRAY;
+        break;
+    case AV_PIX_FMT_GRAY8A:
+        s->bit_depth = 8;
+        s->color_type = PNG_COLOR_TYPE_GRAY_ALPHA;
+        break;
+    case AV_PIX_FMT_YA16BE:
+        s->bit_depth = 16;
+        s->color_type = PNG_COLOR_TYPE_GRAY_ALPHA;
+        break;
+    case AV_PIX_FMT_MONOBLACK:
+        s->bit_depth  = 1;
+        s->color_type = PNG_COLOR_TYPE_GRAY;
+        break;
+    case AV_PIX_FMT_PAL8:
+        s->bit_depth  = 8;
+        s->color_type = PNG_COLOR_TYPE_PALETTE;
+        break;
+    default:
+        return -1;
+    }
+    s->bits_per_pixel = ff_png_get_nb_channels(s->color_type) * s->bit_depth;
+
     return 0;
 }