lavf/segment: add deinit function
[ffmpeg.git] / libavcodec / pngenc.c
index bf7c49e..00c830e 100644 (file)
 #include "bytestream.h"
 #include "huffyuvencdsp.h"
 #include "png.h"
+#include "apng.h"
 
 #include "libavutil/avassert.h"
+#include "libavutil/crc.h"
 #include "libavutil/libm.h"
 #include "libavutil/opt.h"
 #include "libavutil/color_utils.h"
+#include "libavutil/stereo3d.h"
 
 #include <zlib.h>
 
 #define IOBUF_SIZE 4096
 
+typedef struct APNGFctlChunk {
+    uint32_t sequence_number;
+    uint32_t width, height;
+    uint32_t x_offset, y_offset;
+    uint16_t delay_num, delay_den;
+    uint8_t dispose_op, blend_op;
+} APNGFctlChunk;
+
 typedef struct PNGEncContext {
     AVClass *class;
     HuffYUVEncDSPContext hdsp;
@@ -53,6 +64,16 @@ typedef struct PNGEncContext {
     int bit_depth;
     int color_type;
     int bits_per_pixel;
+
+    // APNG
+    uint32_t palette_checksum;   // Used to ensure a single unique palette
+    uint32_t sequence_number;
+
+    AVFrame *prev_frame;
+    AVFrame *last_frame;
+    APNGFctlChunk last_frame_fctl;
+    uint8_t *last_frame_packet;
+    size_t last_frame_packet_size;
 } PNGEncContext;
 
 static void png_get_interlaced_row(uint8_t *dst, int row_size,
@@ -200,25 +221,53 @@ static uint8_t *png_choose_filter(PNGEncContext *s, uint8_t *dst,
 static void png_write_chunk(uint8_t **f, uint32_t tag,
                             const uint8_t *buf, int length)
 {
-    uint32_t crc;
+    const AVCRC *crc_table = av_crc_get_table(AV_CRC_32_IEEE_LE);
+    uint32_t crc = ~0U;
     uint8_t tagbuf[4];
 
     bytestream_put_be32(f, length);
-    crc = crc32(0, Z_NULL, 0);
     AV_WL32(tagbuf, tag);
-    crc = crc32(crc, tagbuf, 4);
+    crc = av_crc(crc_table, crc, tagbuf, 4);
     bytestream_put_be32(f, av_bswap32(tag));
     if (length > 0) {
-        crc = crc32(crc, buf, length);
+        crc = av_crc(crc_table, crc, buf, length);
         memcpy(*f, buf, length);
         *f += length;
     }
-    bytestream_put_be32(f, crc);
+    bytestream_put_be32(f, ~crc);
+}
+
+static void png_write_image_data(AVCodecContext *avctx,
+                                 const uint8_t *buf, int length)
+{
+    PNGEncContext *s = avctx->priv_data;
+    const AVCRC *crc_table = av_crc_get_table(AV_CRC_32_IEEE_LE);
+    uint32_t crc = ~0U;
+
+    if (avctx->codec_id == AV_CODEC_ID_PNG || avctx->frame_number == 0) {
+        png_write_chunk(&s->bytestream, MKTAG('I', 'D', 'A', 'T'), buf, length);
+        return;
+    }
+
+    bytestream_put_be32(&s->bytestream, length + 4);
+
+    bytestream_put_be32(&s->bytestream, MKBETAG('f', 'd', 'A', 'T'));
+    bytestream_put_be32(&s->bytestream, s->sequence_number);
+    crc = av_crc(crc_table, crc, s->bytestream - 8, 8);
+
+    crc = av_crc(crc_table, crc, buf, length);
+    memcpy(s->bytestream, buf, length);
+    s->bytestream += length;
+
+    bytestream_put_be32(&s->bytestream, ~crc);
+
+    ++s->sequence_number;
 }
 
 /* XXX: do filtering */
-static int png_write_row(PNGEncContext *s, const uint8_t *data, int size)
+static int png_write_row(AVCodecContext *avctx, const uint8_t *data, int size)
 {
+    PNGEncContext *s = avctx->priv_data;
     int ret;
 
     s->zstream.avail_in = size;
@@ -229,8 +278,7 @@ static int png_write_row(PNGEncContext *s, const uint8_t *data, int size)
             return -1;
         if (s->zstream.avail_out == 0) {
             if (s->bytestream_end - s->bytestream > IOBUF_SIZE + 100)
-                png_write_chunk(&s->bytestream,
-                                MKTAG('I', 'D', 'A', 'T'), s->buf, IOBUF_SIZE);
+                png_write_image_data(avctx, s->buf, IOBUF_SIZE);
             s->zstream.avail_out = IOBUF_SIZE;
             s->zstream.next_out  = s->buf;
         }
@@ -293,6 +341,7 @@ static int png_get_gama(enum AVColorTransferCharacteristic trc, uint8_t *buf)
 
 static int encode_headers(AVCodecContext *avctx, const AVFrame *pict)
 {
+    AVFrameSideData *side_data;
     PNGEncContext *s = avctx->priv_data;
 
     /* write png header */
@@ -317,6 +366,23 @@ static int encode_headers(AVCodecContext *avctx, const AVFrame *pict)
     }
     png_write_chunk(&s->bytestream, MKTAG('p', 'H', 'Y', 's'), s->buf, 9);
 
+    /* write stereoscopic information */
+    side_data = av_frame_get_side_data(pict, AV_FRAME_DATA_STEREO3D);
+    if (side_data) {
+        AVStereo3D *stereo3d = (AVStereo3D *)side_data->data;
+        switch (stereo3d->type) {
+            case AV_STEREO3D_SIDEBYSIDE:
+                s->buf[0] = ((stereo3d->flags & AV_STEREO3D_FLAG_INVERT) == 0) ? 1 : 0;
+                png_write_chunk(&s->bytestream, MKTAG('s', 'T', 'E', 'R'), s->buf, 1);
+                break;
+            case AV_STEREO3D_2D:
+                break;
+            default:
+                av_log(avctx, AV_LOG_WARNING, "Only side-by-side stereo3d flag can be defined within sTER chunk\n");
+                break;
+        }
+    }
+
     /* write colorspace information */
     if (pict->color_primaries == AVCOL_PRI_BT709 &&
         pict->color_trc == AVCOL_TRC_IEC61966_2_1) {
@@ -370,7 +436,7 @@ static int encode_frame(AVCodecContext *avctx, const AVFrame *pict)
     uint8_t *progressive_buf = NULL;
     uint8_t *top_buf         = NULL;
 
-    row_size = (avctx->width * s->bits_per_pixel + 7) >> 3;
+    row_size = (pict->width * s->bits_per_pixel + 7) >> 3;
 
     crow_base = av_malloc((row_size + 32) << (s->filter_type == PNG_FILTER_VALUE_MIXED));
     if (!crow_base) {
@@ -397,30 +463,30 @@ static int encode_frame(AVCodecContext *avctx, const AVFrame *pict)
         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, s->bits_per_pixel, avctx->width);
+            pass_row_size = ff_png_pass_row_size(pass, s->bits_per_pixel, pict->width);
             if (pass_row_size > 0) {
                 top = NULL;
-                for (y = 0; y < avctx->height; y++)
+                for (y = 0; y < pict->height; y++)
                     if ((ff_png_pass_ymask[pass] << (y & 7)) & 0x80) {
                         ptr = p->data[0] + y * p->linesize[0];
                         FFSWAP(uint8_t *, progressive_buf, top_buf);
                         png_get_interlaced_row(progressive_buf, pass_row_size,
                                                s->bits_per_pixel, pass,
-                                               ptr, avctx->width);
+                                               ptr, pict->width);
                         crow = png_choose_filter(s, crow_buf, progressive_buf,
                                                  top, pass_row_size, s->bits_per_pixel >> 3);
-                        png_write_row(s, crow, pass_row_size + 1);
+                        png_write_row(avctx, crow, pass_row_size + 1);
                         top = progressive_buf;
                     }
             }
         }
     } else {
         top = NULL;
-        for (y = 0; y < avctx->height; y++) {
+        for (y = 0; y < pict->height; y++) {
             ptr = p->data[0] + y * p->linesize[0];
             crow = png_choose_filter(s, crow_buf, ptr, top,
                                      row_size, s->bits_per_pixel >> 3);
-            png_write_row(s, crow, row_size + 1);
+            png_write_row(avctx, crow, row_size + 1);
             top = ptr;
         }
     }
@@ -430,7 +496,7 @@ static int encode_frame(AVCodecContext *avctx, const AVFrame *pict)
         if (ret == Z_OK || ret == Z_STREAM_END) {
             len = IOBUF_SIZE - s->zstream.avail_out;
             if (len > 0 && s->bytestream_end - s->bytestream > len + 100) {
-                png_write_chunk(&s->bytestream, MKTAG('I', 'D', 'A', 'T'), s->buf, len);
+                png_write_image_data(avctx, s->buf, len);
             }
             s->zstream.avail_out = IOBUF_SIZE;
             s->zstream.next_out  = s->buf;
@@ -452,8 +518,8 @@ the_end:
     return ret;
 }
 
-static int encode(AVCodecContext *avctx, AVPacket *pkt,
-                  const AVFrame *pict, int *got_packet)
+static int encode_png(AVCodecContext *avctx, AVPacket *pkt,
+                      const AVFrame *pict, int *got_packet)
 {
     PNGEncContext *s = avctx->priv_data;
     int ret;
@@ -462,14 +528,14 @@ static int encode(AVCodecContext *avctx, AVPacket *pkt,
 
     enc_row_size    = deflateBound(&s->zstream, (avctx->width * s->bits_per_pixel + 7) >> 3);
     max_packet_size =
-        FF_MIN_BUFFER_SIZE + // headers
+        AV_INPUT_BUFFER_MIN_SIZE + // headers
         avctx->height * (
             enc_row_size +
             12 * (((int64_t)enc_row_size + IOBUF_SIZE - 1) / IOBUF_SIZE) // IDAT * ceil(enc_row_size / IOBUF_SIZE)
         );
     if (max_packet_size > INT_MAX)
         return AVERROR(ENOMEM);
-    ret = ff_alloc_packet2(avctx, pkt, max_packet_size);
+    ret = ff_alloc_packet2(avctx, pkt, max_packet_size, 0);
     if (ret < 0)
         return ret;
 
@@ -497,6 +563,419 @@ static int encode(AVCodecContext *avctx, AVPacket *pkt,
     return 0;
 }
 
+static int apng_do_inverse_blend(AVFrame *output, const AVFrame *input,
+                                  APNGFctlChunk *fctl_chunk, uint8_t bpp)
+{
+    // output: background, input: foreground
+    // output the image such that when blended with the background, will produce the foreground
+
+    unsigned int x, y;
+    unsigned int leftmost_x = input->width;
+    unsigned int rightmost_x = 0;
+    unsigned int topmost_y = input->height;
+    unsigned int bottommost_y = 0;
+    const uint8_t *input_data = input->data[0];
+    uint8_t *output_data = output->data[0];
+    ptrdiff_t input_linesize = input->linesize[0];
+    ptrdiff_t output_linesize = output->linesize[0];
+
+    // Find bounding box of changes
+    for (y = 0; y < input->height; ++y) {
+        for (x = 0; x < input->width; ++x) {
+            if (!memcmp(input_data + bpp * x, output_data + bpp * x, bpp))
+                continue;
+
+            if (x < leftmost_x)
+                leftmost_x = x;
+            if (x >= rightmost_x)
+                rightmost_x = x + 1;
+            if (y < topmost_y)
+                topmost_y = y;
+            if (y >= bottommost_y)
+                bottommost_y = y + 1;
+        }
+
+        input_data += input_linesize;
+        output_data += output_linesize;
+    }
+
+    if (leftmost_x == input->width && rightmost_x == 0) {
+        // Empty frame
+        // APNG does not support empty frames, so we make it a 1x1 frame
+        leftmost_x = topmost_y = 0;
+        rightmost_x = bottommost_y = 1;
+    }
+
+    // Do actual inverse blending
+    if (fctl_chunk->blend_op == APNG_BLEND_OP_SOURCE) {
+        output_data = output->data[0];
+        for (y = topmost_y; y < bottommost_y; ++y) {
+            memcpy(output_data,
+                   input->data[0] + input_linesize * y + bpp * leftmost_x,
+                   bpp * (rightmost_x - leftmost_x));
+            output_data += output_linesize;
+        }
+    } else { // APNG_BLEND_OP_OVER
+        size_t transparent_palette_index;
+        uint32_t *palette;
+
+        switch (input->format) {
+        case AV_PIX_FMT_RGBA64BE:
+        case AV_PIX_FMT_YA16BE:
+        case AV_PIX_FMT_RGBA:
+        case AV_PIX_FMT_GRAY8A:
+            break;
+
+        case AV_PIX_FMT_PAL8:
+            palette = (uint32_t*)input->data[1];
+            for (transparent_palette_index = 0; transparent_palette_index < 256; ++transparent_palette_index)
+                if (palette[transparent_palette_index] >> 24 == 0)
+                    break;
+            break;
+
+        default:
+            // No alpha, so blending not possible
+            return -1;
+        }
+
+        for (y = topmost_y; y < bottommost_y; ++y) {
+            uint8_t *foreground = input->data[0] + input_linesize * y + bpp * leftmost_x;
+            uint8_t *background = output->data[0] + output_linesize * y + bpp * leftmost_x;
+            output_data = output->data[0] + output_linesize * (y - topmost_y);
+            for (x = leftmost_x; x < rightmost_x; ++x, foreground += bpp, background += bpp, output_data += bpp) {
+                if (!memcmp(foreground, background, bpp)) {
+                    if (input->format == AV_PIX_FMT_PAL8) {
+                        if (transparent_palette_index == 256) {
+                            // Need fully transparent colour, but none exists
+                            return -1;
+                        }
+
+                        *output_data = transparent_palette_index;
+                    } else {
+                        memset(output_data, 0, bpp);
+                    }
+                    continue;
+                }
+
+                // Check for special alpha values, since full inverse
+                // alpha-on-alpha blending is rarely possible, and when
+                // possible, doesn't compress much better than
+                // APNG_BLEND_OP_SOURCE blending
+                switch (input->format) {
+                case AV_PIX_FMT_RGBA64BE:
+                    if (((uint16_t*)foreground)[3] == 0xffff ||
+                        ((uint16_t*)background)[3] == 0)
+                        break;
+                    return -1;
+
+                case AV_PIX_FMT_YA16BE:
+                    if (((uint16_t*)foreground)[1] == 0xffff ||
+                        ((uint16_t*)background)[1] == 0)
+                        break;
+                    return -1;
+
+                case AV_PIX_FMT_RGBA:
+                    if (foreground[3] == 0xff || background[3] == 0)
+                        break;
+                    return -1;
+
+                case AV_PIX_FMT_GRAY8A:
+                    if (foreground[1] == 0xff || background[1] == 0)
+                        break;
+                    return -1;
+
+                case AV_PIX_FMT_PAL8:
+                    if (palette[*foreground] >> 24 == 0xff ||
+                        palette[*background] >> 24 == 0)
+                        break;
+                    return -1;
+                }
+
+                memmove(output_data, foreground, bpp);
+            }
+        }
+    }
+
+    output->width = rightmost_x - leftmost_x;
+    output->height = bottommost_y - topmost_y;
+    fctl_chunk->width = output->width;
+    fctl_chunk->height = output->height;
+    fctl_chunk->x_offset = leftmost_x;
+    fctl_chunk->y_offset = topmost_y;
+
+    return 0;
+}
+
+static int apng_encode_frame(AVCodecContext *avctx, const AVFrame *pict,
+                             APNGFctlChunk *best_fctl_chunk, APNGFctlChunk *best_last_fctl_chunk)
+{
+    PNGEncContext *s = avctx->priv_data;
+    int ret;
+    unsigned int y;
+    AVFrame* diffFrame;
+    uint8_t bpp = (s->bits_per_pixel + 7) >> 3;
+    uint8_t *original_bytestream, *original_bytestream_end;
+    uint8_t *temp_bytestream = 0, *temp_bytestream_end;
+    uint32_t best_sequence_number;
+    uint8_t *best_bytestream;
+    size_t best_bytestream_size = SIZE_MAX;
+    APNGFctlChunk last_fctl_chunk = *best_last_fctl_chunk;
+    APNGFctlChunk fctl_chunk = *best_fctl_chunk;
+
+    if (avctx->frame_number == 0) {
+        best_fctl_chunk->width = pict->width;
+        best_fctl_chunk->height = pict->height;
+        best_fctl_chunk->x_offset = 0;
+        best_fctl_chunk->y_offset = 0;
+        best_fctl_chunk->blend_op = APNG_BLEND_OP_SOURCE;
+        return encode_frame(avctx, pict);
+    }
+
+    diffFrame = av_frame_alloc();
+    if (!diffFrame)
+        return AVERROR(ENOMEM);
+
+    diffFrame->format = pict->format;
+    diffFrame->width = pict->width;
+    diffFrame->height = pict->height;
+    if ((ret = av_frame_get_buffer(diffFrame, 32)) < 0)
+        goto fail;
+
+    original_bytestream = s->bytestream;
+    original_bytestream_end = s->bytestream_end;
+
+    temp_bytestream = av_malloc(original_bytestream_end - original_bytestream);
+    temp_bytestream_end = temp_bytestream + (original_bytestream_end - original_bytestream);
+    if (!temp_bytestream) {
+        ret = AVERROR(ENOMEM);
+        goto fail;
+    }
+
+    for (last_fctl_chunk.dispose_op = 0; last_fctl_chunk.dispose_op < 3; ++last_fctl_chunk.dispose_op) {
+        // 0: APNG_DISPOSE_OP_NONE
+        // 1: APNG_DISPOSE_OP_BACKGROUND
+        // 2: APNG_DISPOSE_OP_PREVIOUS
+
+        for (fctl_chunk.blend_op = 0; fctl_chunk.blend_op < 2; ++fctl_chunk.blend_op) {
+            // 0: APNG_BLEND_OP_SOURCE
+            // 1: APNG_BLEND_OP_OVER
+
+            uint32_t original_sequence_number = s->sequence_number, sequence_number;
+            uint8_t *bytestream_start = s->bytestream;
+            size_t bytestream_size;
+
+            // Do disposal
+            if (last_fctl_chunk.dispose_op != APNG_DISPOSE_OP_PREVIOUS) {
+                diffFrame->width = pict->width;
+                diffFrame->height = pict->height;
+                ret = av_frame_copy(diffFrame, s->last_frame);
+                if (ret < 0)
+                    goto fail;
+
+                if (last_fctl_chunk.dispose_op == APNG_DISPOSE_OP_BACKGROUND) {
+                    for (y = last_fctl_chunk.y_offset; y < last_fctl_chunk.y_offset + last_fctl_chunk.height; ++y) {
+                        size_t row_start = diffFrame->linesize[0] * y + bpp * last_fctl_chunk.x_offset;
+                        memset(diffFrame->data[0] + row_start, 0, bpp * last_fctl_chunk.width);
+                    }
+                }
+            } else {
+                if (!s->prev_frame)
+                    continue;
+
+                diffFrame->width = pict->width;
+                diffFrame->height = pict->height;
+                ret = av_frame_copy(diffFrame, s->prev_frame);
+                if (ret < 0)
+                    goto fail;
+            }
+
+            // Do inverse blending
+            if (apng_do_inverse_blend(diffFrame, pict, &fctl_chunk, bpp) < 0)
+                continue;
+
+            // Do encoding
+            ret = encode_frame(avctx, diffFrame);
+            sequence_number = s->sequence_number;
+            s->sequence_number = original_sequence_number;
+            bytestream_size = s->bytestream - bytestream_start;
+            s->bytestream = bytestream_start;
+            if (ret < 0)
+                goto fail;
+
+            if (bytestream_size < best_bytestream_size) {
+                *best_fctl_chunk = fctl_chunk;
+                *best_last_fctl_chunk = last_fctl_chunk;
+
+                best_sequence_number = sequence_number;
+                best_bytestream = s->bytestream;
+                best_bytestream_size = bytestream_size;
+
+                if (best_bytestream == original_bytestream) {
+                    s->bytestream = temp_bytestream;
+                    s->bytestream_end = temp_bytestream_end;
+                } else {
+                    s->bytestream = original_bytestream;
+                    s->bytestream_end = original_bytestream_end;
+                }
+            }
+        }
+    }
+
+    s->sequence_number = best_sequence_number;
+    s->bytestream = original_bytestream + best_bytestream_size;
+    s->bytestream_end = original_bytestream_end;
+    if (best_bytestream != original_bytestream)
+        memcpy(original_bytestream, best_bytestream, best_bytestream_size);
+
+    ret = 0;
+
+fail:
+    av_freep(&temp_bytestream);
+    av_frame_free(&diffFrame);
+    return ret;
+}
+
+static int encode_apng(AVCodecContext *avctx, AVPacket *pkt,
+                       const AVFrame *pict, int *got_packet)
+{
+    PNGEncContext *s = avctx->priv_data;
+    int ret;
+    int enc_row_size;
+    size_t max_packet_size;
+    APNGFctlChunk fctl_chunk = {0};
+
+    if (pict && avctx->codec_id == AV_CODEC_ID_APNG && s->color_type == PNG_COLOR_TYPE_PALETTE) {
+        uint32_t checksum = ~av_crc(av_crc_get_table(AV_CRC_32_IEEE_LE), ~0U, pict->data[1], 256 * sizeof(uint32_t));
+
+        if (avctx->frame_number == 0) {
+            s->palette_checksum = checksum;
+        } else if (checksum != s->palette_checksum) {
+            av_log(avctx, AV_LOG_ERROR,
+                   "Input contains more than one unique palette. APNG does not support multiple palettes.\n");
+            return -1;
+        }
+    }
+
+    enc_row_size    = deflateBound(&s->zstream, (avctx->width * s->bits_per_pixel + 7) >> 3);
+    max_packet_size =
+        AV_INPUT_BUFFER_MIN_SIZE + // headers
+        avctx->height * (
+            enc_row_size +
+            (4 + 12) * (((int64_t)enc_row_size + IOBUF_SIZE - 1) / IOBUF_SIZE) // fdAT * ceil(enc_row_size / IOBUF_SIZE)
+        );
+    if (max_packet_size > INT_MAX)
+        return AVERROR(ENOMEM);
+
+    if (avctx->frame_number == 0) {
+        if (!pict)
+            return AVERROR(EINVAL);
+
+        s->bytestream = avctx->extradata = av_malloc(FF_MIN_BUFFER_SIZE);
+        if (!avctx->extradata)
+            return AVERROR(ENOMEM);
+
+        ret = encode_headers(avctx, pict);
+        if (ret < 0)
+            return ret;
+
+        avctx->extradata_size = s->bytestream - avctx->extradata;
+
+        s->last_frame_packet = av_malloc(max_packet_size);
+        if (!s->last_frame_packet)
+            return AVERROR(ENOMEM);
+    } else if (s->last_frame) {
+        ret = ff_alloc_packet2(avctx, pkt, max_packet_size, 0);
+        if (ret < 0)
+            return ret;
+
+        memcpy(pkt->data, s->last_frame_packet, s->last_frame_packet_size);
+        pkt->size = s->last_frame_packet_size;
+        pkt->pts = pkt->dts = s->last_frame->pts;
+    }
+
+    if (pict) {
+        s->bytestream_start =
+        s->bytestream       = s->last_frame_packet;
+        s->bytestream_end   = s->bytestream + max_packet_size;
+
+        // We're encoding the frame first, so we have to do a bit of shuffling around
+        // to have the image data write to the correct place in the buffer
+        fctl_chunk.sequence_number = s->sequence_number;
+        ++s->sequence_number;
+        s->bytestream += 26 + 12;
+
+        ret = apng_encode_frame(avctx, pict, &fctl_chunk, &s->last_frame_fctl);
+        if (ret < 0)
+            return ret;
+
+        fctl_chunk.delay_num = 0; // delay filled in during muxing
+        fctl_chunk.delay_den = 0;
+    } else {
+        s->last_frame_fctl.dispose_op = APNG_DISPOSE_OP_NONE;
+    }
+
+    if (s->last_frame) {
+        uint8_t* last_fctl_chunk_start = pkt->data;
+        uint8_t buf[26];
+
+        AV_WB32(buf + 0, s->last_frame_fctl.sequence_number);
+        AV_WB32(buf + 4, s->last_frame_fctl.width);
+        AV_WB32(buf + 8, s->last_frame_fctl.height);
+        AV_WB32(buf + 12, s->last_frame_fctl.x_offset);
+        AV_WB32(buf + 16, s->last_frame_fctl.y_offset);
+        AV_WB16(buf + 20, s->last_frame_fctl.delay_num);
+        AV_WB16(buf + 22, s->last_frame_fctl.delay_den);
+        buf[24] = s->last_frame_fctl.dispose_op;
+        buf[25] = s->last_frame_fctl.blend_op;
+        png_write_chunk(&last_fctl_chunk_start, MKTAG('f', 'c', 'T', 'L'), buf, 26);
+
+        *got_packet = 1;
+    }
+
+    if (pict) {
+        if (!s->last_frame) {
+            s->last_frame = av_frame_alloc();
+            if (!s->last_frame)
+                return AVERROR(ENOMEM);
+        } else if (s->last_frame_fctl.dispose_op != APNG_DISPOSE_OP_PREVIOUS) {
+            if (!s->prev_frame) {
+                s->prev_frame = av_frame_alloc();
+                if (!s->prev_frame)
+                    return AVERROR(ENOMEM);
+
+                s->prev_frame->format = pict->format;
+                s->prev_frame->width = pict->width;
+                s->prev_frame->height = pict->height;
+                if ((ret = av_frame_get_buffer(s->prev_frame, 32)) < 0)
+                    return ret;
+            }
+
+            // Do disposal, but not blending
+            av_frame_copy(s->prev_frame, s->last_frame);
+            if (s->last_frame_fctl.dispose_op == APNG_DISPOSE_OP_BACKGROUND) {
+                uint32_t y;
+                uint8_t bpp = (s->bits_per_pixel + 7) >> 3;
+                for (y = s->last_frame_fctl.y_offset; y < s->last_frame_fctl.y_offset + s->last_frame_fctl.height; ++y) {
+                    size_t row_start = s->prev_frame->linesize[0] * y + bpp * s->last_frame_fctl.x_offset;
+                    memset(s->prev_frame->data[0] + row_start, 0, bpp * s->last_frame_fctl.width);
+                }
+            }
+        }
+
+        av_frame_unref(s->last_frame);
+        ret = av_frame_ref(s->last_frame, (AVFrame*)pict);
+        if (ret < 0)
+            return ret;
+
+        s->last_frame_fctl = fctl_chunk;
+        s->last_frame_packet_size = s->bytestream - s->bytestream_start;
+    } else {
+        av_frame_free(&s->last_frame);
+    }
+
+    return 0;
+}
+
 static av_cold int png_enc_init(AVCodecContext *avctx)
 {
     PNGEncContext *s = avctx->priv_data;
@@ -519,18 +998,24 @@ static av_cold int png_enc_init(AVCodecContext *avctx)
         avctx->bits_per_coded_sample = 8;
     }
 
-    avctx->coded_frame = av_frame_alloc();
-    if (!avctx->coded_frame)
-        return AVERROR(ENOMEM);
-
+#if FF_API_CODED_FRAME
+FF_DISABLE_DEPRECATION_WARNINGS
     avctx->coded_frame->pict_type = AV_PICTURE_TYPE_I;
     avctx->coded_frame->key_frame = 1;
+FF_ENABLE_DEPRECATION_WARNINGS
+#endif
 
     ff_huffyuvencdsp_init(&s->hdsp);
 
-    s->filter_type = av_clip(avctx->prediction_method,
-                             PNG_FILTER_VALUE_NONE,
-                             PNG_FILTER_VALUE_MIXED);
+#if FF_API_PRIVATE_OPT
+FF_DISABLE_DEPRECATION_WARNINGS
+    if (avctx->prediction_method)
+        s->filter_type = av_clip(avctx->prediction_method,
+                                 PNG_FILTER_VALUE_NONE,
+                                 PNG_FILTER_VALUE_MIXED);
+FF_ENABLE_DEPRECATION_WARNINGS
+#endif
+
     if (avctx->pix_fmt == AV_PIX_FMT_MONOBLACK)
         s->filter_type = PNG_FILTER_VALUE_NONE;
 
@@ -541,7 +1026,7 @@ static av_cold int png_enc_init(AVCodecContext *avctx)
       s->dpm = s->dpi * 10000 / 254;
     }
 
-    s->is_progressive = !!(avctx->flags & CODEC_FLAG_INTERLACED_DCT);
+    s->is_progressive = !!(avctx->flags & AV_CODEC_FLAG_INTERLACED_DCT);
     switch (avctx->pix_fmt) {
     case AV_PIX_FMT_RGBA64BE:
         s->bit_depth = 16;
@@ -605,7 +1090,9 @@ static av_cold int png_enc_close(AVCodecContext *avctx)
     PNGEncContext *s = avctx->priv_data;
 
     deflateEnd(&s->zstream);
-    av_frame_free(&avctx->coded_frame);
+    av_frame_free(&s->last_frame);
+    av_frame_free(&s->prev_frame);
+    av_freep(&s->last_frame_packet);
     return 0;
 }
 
@@ -614,7 +1101,14 @@ static av_cold int png_enc_close(AVCodecContext *avctx)
 static const AVOption options[] = {
     {"dpi", "Set image resolution (in dots per inch)",  OFFSET(dpi), AV_OPT_TYPE_INT, {.i64 = 0}, 0, 0x10000, VE},
     {"dpm", "Set image resolution (in dots per meter)", OFFSET(dpm), AV_OPT_TYPE_INT, {.i64 = 0}, 0, 0x10000, VE},
-    { NULL }
+    { "pred", "Prediction method", OFFSET(filter_type), AV_OPT_TYPE_INT, { .i64 = PNG_FILTER_VALUE_NONE }, PNG_FILTER_VALUE_NONE, PNG_FILTER_VALUE_MIXED, VE, "pred" },
+        { "none",  NULL, 0, AV_OPT_TYPE_CONST, { .i64 = PNG_FILTER_VALUE_NONE },  INT_MIN, INT_MAX, VE, "pred" },
+        { "sub",   NULL, 0, AV_OPT_TYPE_CONST, { .i64 = PNG_FILTER_VALUE_SUB },   INT_MIN, INT_MAX, VE, "pred" },
+        { "up",    NULL, 0, AV_OPT_TYPE_CONST, { .i64 = PNG_FILTER_VALUE_UP },    INT_MIN, INT_MAX, VE, "pred" },
+        { "avg",   NULL, 0, AV_OPT_TYPE_CONST, { .i64 = PNG_FILTER_VALUE_AVG },   INT_MIN, INT_MAX, VE, "pred" },
+        { "paeth", NULL, 0, AV_OPT_TYPE_CONST, { .i64 = PNG_FILTER_VALUE_PAETH }, INT_MIN, INT_MAX, VE, "pred" },
+        { "mixed", NULL, 0, AV_OPT_TYPE_CONST, { .i64 = PNG_FILTER_VALUE_MIXED }, INT_MIN, INT_MAX, VE, "pred" },
+    { NULL},
 };
 
 static const AVClass pngenc_class = {
@@ -624,6 +1118,13 @@ static const AVClass pngenc_class = {
     .version    = LIBAVUTIL_VERSION_INT,
 };
 
+static const AVClass apngenc_class = {
+    .class_name = "APNG encoder",
+    .item_name  = av_default_item_name,
+    .option     = options,
+    .version    = LIBAVUTIL_VERSION_INT,
+};
+
 AVCodec ff_png_encoder = {
     .name           = "png",
     .long_name      = NULL_IF_CONFIG_SMALL("PNG (Portable Network Graphics) image"),
@@ -632,8 +1133,8 @@ AVCodec ff_png_encoder = {
     .priv_data_size = sizeof(PNGEncContext),
     .init           = png_enc_init,
     .close          = png_enc_close,
-    .encode2        = encode,
-    .capabilities   = CODEC_CAP_FRAME_THREADS | CODEC_CAP_INTRA_ONLY,
+    .encode2        = encode_png,
+    .capabilities   = AV_CODEC_CAP_FRAME_THREADS | AV_CODEC_CAP_INTRA_ONLY,
     .pix_fmts       = (const enum AVPixelFormat[]) {
         AV_PIX_FMT_RGB24, AV_PIX_FMT_RGBA,
         AV_PIX_FMT_RGB48BE, AV_PIX_FMT_RGBA64BE,
@@ -644,3 +1145,24 @@ AVCodec ff_png_encoder = {
     },
     .priv_class     = &pngenc_class,
 };
+
+AVCodec ff_apng_encoder = {
+    .name           = "apng",
+    .long_name      = NULL_IF_CONFIG_SMALL("APNG (Animated Portable Network Graphics) image"),
+    .type           = AVMEDIA_TYPE_VIDEO,
+    .id             = AV_CODEC_ID_APNG,
+    .priv_data_size = sizeof(PNGEncContext),
+    .init           = png_enc_init,
+    .close          = png_enc_close,
+    .encode2        = encode_apng,
+    .capabilities   = CODEC_CAP_DELAY,
+    .pix_fmts       = (const enum AVPixelFormat[]) {
+        AV_PIX_FMT_RGB24, AV_PIX_FMT_RGBA,
+        AV_PIX_FMT_RGB48BE, AV_PIX_FMT_RGBA64BE,
+        AV_PIX_FMT_PAL8,
+        AV_PIX_FMT_GRAY8, AV_PIX_FMT_GRAY8A,
+        AV_PIX_FMT_GRAY16BE, AV_PIX_FMT_YA16BE,
+        AV_PIX_FMT_MONOBLACK, AV_PIX_FMT_NONE
+    },
+    .priv_class     = &apngenc_class,
+};