Support the Hap chunked frame format

Signed-off-by: Vittorio Giovara <vittorio.giovara@gmail.com>

6 files changed, 414 insertions, 97 deletions

diff --git a/libavcodec/Makefile b/libavcodec/Makefile
index 40f653b53b..a6e88c7093 100644
--- a/libavcodec/Makefile
+++ b/libavcodec/Makefile
@@ -243,8 +243,8 @@ OBJS-$(CONFIG_H264_MMAL_DECODER)       += mmaldec.o
 OBJS-$(CONFIG_H264_NVENC_ENCODER)      += nvenc_h264.o
 OBJS-$(CONFIG_H264_QSV_DECODER)        += qsvdec_h2645.o
 OBJS-$(CONFIG_H264_QSV_ENCODER)        += qsvenc_h264.o
-OBJS-$(CONFIG_HAP_DECODER)             += hapdec.o
-OBJS-$(CONFIG_HAP_ENCODER)             += hapenc.o
+OBJS-$(CONFIG_HAP_DECODER)             += hapdec.o hap.o
+OBJS-$(CONFIG_HAP_ENCODER)             += hapenc.o hap.o
 OBJS-$(CONFIG_HEVC_DECODER)            += hevc.o hevc_mvs.o hevc_ps.o hevc_sei.o \
                                           hevc_cabac.o hevc_refs.o hevcpred.o    \
                                           hevcdsp.o hevc_filter.o hevc_parse.o hevc_data.o
diff --git a/libavcodec/hap.h b/libavcodec/hap.h
index a0fc2e0bf3..9d847f7b86 100644
--- a/libavcodec/hap.h
+++ b/libavcodec/hap.h
@@ -1,6 +1,7 @@
 /*
  * Vidvox Hap
  * Copyright (C) 2015 Vittorio Giovara <vittorio.giovara@gmail.com>
+ * Copyright (C) 2015 Tom Butterworth <bangnoise@gmail.com>
  *
  * This file is part of Libav.
  *
@@ -41,20 +42,39 @@ enum HapCompressor {
     HAP_COMP_COMPLEX = 0xC0,
 };
 
+enum HapSectionType {
+    HAP_ST_DECODE_INSTRUCTIONS = 0x01,
+    HAP_ST_COMPRESSOR_TABLE    = 0x02,
+    HAP_ST_SIZE_TABLE          = 0x03,
+    HAP_ST_OFFSET_TABLE        = 0x04,
+};
+
+typedef struct HapChunk {
+    enum HapCompressor compressor;
+    int compressed_offset;
+    size_t compressed_size;
+    int uncompressed_offset;
+    size_t uncompressed_size;
+} HapChunk;
+
 typedef struct HapContext {
     AVClass *class;
 
     TextureDSPContext dxtc;
     GetByteContext gbc;
 
-    int section_type;        /* Header type */
+    enum HapTextureFormat opt_tex_fmt; /* Texture type (encoder only) */
+    int opt_chunk_count; /* User-requested chunk count (encoder only) */
+
+    int chunk_count;
+    HapChunk *chunks;
+    int *chunk_results;      /* Results from threaded operations */
 
     int tex_rat;             /* Compression ratio */
     const uint8_t *tex_data; /* Compressed texture */
-    uint8_t *tex_buf;        /* Uncompressed texture */
+    uint8_t *tex_buf;        /* Buffer for compressed texture */
     size_t tex_size;         /* Size of the compressed texture */
 
-    uint8_t *snappied;       /* Buffer interacting with snappy */
     size_t max_snappy;       /* Maximum compressed size for snappy buffer */
 
     int slice_count;         /* Number of slices for threaded operations */
@@ -63,4 +83,16 @@ typedef struct HapContext {
     int (*tex_fun)(uint8_t *dst, ptrdiff_t stride, const uint8_t *block);
 } HapContext;
 
+/*
+ * Set the number of chunks in the frame. Returns 0 on success or an error if:
+ * - first_in_frame is 0 and the number of chunks has changed
+ * - any other error occurs
+ */
+int ff_hap_set_chunk_count(HapContext *ctx, int count, int first_in_frame);
+
+/*
+ * Free resources associated with the context
+ */
+av_cold void ff_hap_free_context(HapContext *ctx);
+
 #endif /* AVCODEC_HAP_H */
diff --git a/libavcodec/hapdec.c b/libavcodec/hapdec.c
index 46dda0400d..8f5365b269 100644
--- a/libavcodec/hapdec.c
+++ b/libavcodec/hapdec.c
@@ -1,6 +1,7 @@
 /*
  * Vidvox Hap decoder
  * Copyright (C) 2015 Vittorio Giovara <vittorio.giovara@gmail.com>
+ * Copyright (C) 2015 Tom Butterworth <bangnoise@gmail.com>
  *
  * This file is part of Libav.
  *
@@ -36,6 +37,7 @@
 #include "bytestream.h"
 #include "hap.h"
 #include "internal.h"
+#include "memory.h"
 #include "snappy.h"
 #include "texturedsp.h"
 #include "thread.h"
@@ -43,85 +45,224 @@
 /* The first three bytes are the size of the section past the header, or zero
  * if the length is stored in the next long word. The fourth byte in the first
  * long word indicates the type of the current section. */
-static int parse_section_header(AVCodecContext *avctx)
+static int parse_section_header(GetByteContext *gbc, int *section_size,
+                                enum HapSectionType *section_type)
 {
-    HapContext *ctx = avctx->priv_data;
-    GetByteContext *gbc = &ctx->gbc;
-    int length;
-
     if (bytestream2_get_bytes_left(gbc) < 4)
         return AVERROR_INVALIDDATA;
 
-    length = bytestream2_get_le24(gbc);
+    *section_size = bytestream2_get_le24(gbc);
+    *section_type = bytestream2_get_byte(gbc);
 
-    ctx->section_type = bytestream2_get_byte(gbc);
-
-    if (length == 0) {
+    if (*section_size == 0) {
         if (bytestream2_get_bytes_left(gbc) < 4)
             return AVERROR_INVALIDDATA;
-        length = bytestream2_get_le32(gbc);
+
+        *section_size = bytestream2_get_le32(gbc);
     }
 
-    if (length > bytestream2_get_bytes_left(gbc) || length == 0)
+    if (*section_size > bytestream2_get_bytes_left(gbc))
         return AVERROR_INVALIDDATA;
+    else
+        return 0;
+}
 
-    return length;
+static int hap_parse_decode_instructions(HapContext *ctx, int size)
+{
+    GetByteContext *gbc = &ctx->gbc;
+    int section_size;
+    enum HapSectionType section_type;
+    int is_first_table = 1, had_offsets = 0, had_compressors = 0, had_sizes = 0;
+    int i, ret;
+
+    while (size > 0) {
+        int stream_remaining = bytestream2_get_bytes_left(gbc);
+        ret = parse_section_header(gbc, &section_size, &section_type);
+        if (ret != 0)
+            return ret;
+
+        size -= stream_remaining - bytestream2_get_bytes_left(gbc);
+
+        switch (section_type) {
+            case HAP_ST_COMPRESSOR_TABLE:
+                ret = ff_hap_set_chunk_count(ctx, section_size, is_first_table);
+                if (ret != 0)
+                    return ret;
+                for (i = 0; i < section_size; i++) {
+                    ctx->chunks[i].compressor = bytestream2_get_byte(gbc) << 4;
+                }
+                had_compressors = 1;
+                is_first_table = 0;
+                break;
+            case HAP_ST_SIZE_TABLE:
+                ret = ff_hap_set_chunk_count(ctx, section_size / 4, is_first_table);
+                if (ret != 0)
+                    return ret;
+                for (i = 0; i < section_size / 4; i++) {
+                    ctx->chunks[i].compressed_size = bytestream2_get_le32(gbc);
+                }
+                had_sizes = 1;
+                is_first_table = 0;
+                break;
+            case HAP_ST_OFFSET_TABLE:
+                ret = ff_hap_set_chunk_count(ctx, section_size / 4, is_first_table);
+                if (ret != 0)
+                    return ret;
+                for (i = 0; i < section_size / 4; i++) {
+                    ctx->chunks[i].compressed_offset = bytestream2_get_le32(gbc);
+                }
+                had_offsets = 1;
+                is_first_table = 0;
+                break;
+            default:
+                break;
+        }
+        size -= section_size;
+    }
+
+    if (!had_sizes || !had_compressors)
+        return AVERROR_INVALIDDATA;
+
+    /* The offsets table is optional. If not present than calculate offsets by
+     * summing the sizes of preceding chunks. */
+    if (!had_offsets) {
+        size_t running_size = 0;
+        for (i = 0; i < ctx->chunk_count; i++) {
+            ctx->chunks[i].compressed_offset = running_size;
+            running_size += ctx->chunks[i].compressed_size;
+        }
+    }
+
+    return 0;
+}
+
+static int hap_can_use_tex_in_place(HapContext *ctx)
+{
+    int i;
+    size_t running_offset = 0;
+    for (i = 0; i < ctx->chunk_count; i++) {
+        if (ctx->chunks[i].compressed_offset != running_offset
+            || ctx->chunks[i].compressor != HAP_COMP_NONE)
+            return 0;
+        running_offset += ctx->chunks[i].compressed_size;
+    }
+    return 1;
 }
 
-/* Prepare the texture to be decompressed */
-static int setup_texture(AVCodecContext *avctx, size_t length)
+static int hap_parse_frame_header(AVCodecContext *avctx)
 {
     HapContext *ctx = avctx->priv_data;
     GetByteContext *gbc = &ctx->gbc;
-    int64_t snappy_size;
+    int section_size;
+    enum HapSectionType section_type;
     const char *compressorstr;
-    int ret;
+    int i, ret;
+
+    ret = parse_section_header(gbc, &section_size, &section_type);
+    if (ret != 0)
+        return ret;
 
-    if ((avctx->codec_tag == MKTAG('H','a','p','1') && (ctx->section_type & 0x0F) != HAP_FMT_RGBDXT1) ||
-        (avctx->codec_tag == MKTAG('H','a','p','5') && (ctx->section_type & 0x0F) != HAP_FMT_RGBADXT5) ||
-        (avctx->codec_tag == MKTAG('H','a','p','Y') && (ctx->section_type & 0x0F) != HAP_FMT_YCOCGDXT5)) {
+    if ((avctx->codec_tag == MKTAG('H','a','p','1') && (section_type & 0x0F) != HAP_FMT_RGBDXT1) ||
+        (avctx->codec_tag == MKTAG('H','a','p','5') && (section_type & 0x0F) != HAP_FMT_RGBADXT5) ||
+        (avctx->codec_tag == MKTAG('H','a','p','Y') && (section_type & 0x0F) != HAP_FMT_YCOCGDXT5)) {
         av_log(avctx, AV_LOG_ERROR,
-               "Invalid texture format %#04x.\n", ctx->section_type & 0x0F);
+               "Invalid texture format %#04x.\n", section_type & 0x0F);
         return AVERROR_INVALIDDATA;
     }
 
-    switch (ctx->section_type & 0xF0) {
-    case HAP_COMP_NONE:
-        /* Only DXTC texture compression */
-        ctx->tex_data = gbc->buffer;
-        ctx->tex_size = length;
-        compressorstr = "none";
-        break;
-    case HAP_COMP_SNAPPY:
-        snappy_size = ff_snappy_peek_uncompressed_length(gbc);
-        ret = av_reallocp(&ctx->snappied, snappy_size);
-        if (ret < 0) {
-            return ret;
+    switch (section_type & 0xF0) {
+        case HAP_COMP_NONE:
+        case HAP_COMP_SNAPPY:
+            ret = ff_hap_set_chunk_count(ctx, 1, 1);
+            if (ret == 0) {
+                ctx->chunks[0].compressor = section_type & 0xF0;
+                ctx->chunks[0].compressed_offset = 0;
+                ctx->chunks[0].compressed_size = section_size;
+            }
+            if (ctx->chunks[0].compressor == HAP_COMP_NONE) {
+                compressorstr = "none";
+            } else {
+                compressorstr = "snappy";
+            }
+            break;
+        case HAP_COMP_COMPLEX:
+            ret = parse_section_header(gbc, &section_size, &section_type);
+            if (ret == 0 && section_type != HAP_ST_DECODE_INSTRUCTIONS)
+                ret = AVERROR_INVALIDDATA;
+            if (ret == 0)
+                ret = hap_parse_decode_instructions(ctx, section_size);
+            compressorstr = "complex";
+            break;
+        default:
+            ret = AVERROR_INVALIDDATA;
+            break;
+    }
+
+    if (ret != 0)
+        return ret;
+
+    /* Check the frame is valid and read the uncompressed chunk sizes */
+    ctx->tex_size = 0;
+    for (i = 0; i < ctx->chunk_count; i++) {
+        HapChunk *chunk = &ctx->chunks[i];
+
+        /* Check the compressed buffer is valid */
+        if (chunk->compressed_offset + chunk->compressed_size > bytestream2_get_bytes_left(gbc))
+            return AVERROR_INVALIDDATA;
+
+        /* Chunks are unpacked sequentially, ctx->tex_size is the uncompressed
+         * size thus far */
+        chunk->uncompressed_offset = ctx->tex_size;
+
+        /* Fill out uncompressed size */
+        if (chunk->compressor == HAP_COMP_SNAPPY) {
+            GetByteContext gbc_tmp;
+            int64_t uncompressed_size;
+            bytestream2_init(&gbc_tmp, gbc->buffer + chunk->compressed_offset,
+                             chunk->compressed_size);
+            uncompressed_size = ff_snappy_peek_uncompressed_length(&gbc_tmp);
+            if (uncompressed_size < 0) {
+                return uncompressed_size;
+            }
+            chunk->uncompressed_size = uncompressed_size;
+        } else if (chunk->compressor == HAP_COMP_NONE) {
+            chunk->uncompressed_size = chunk->compressed_size;
+        } else {
+            return AVERROR_INVALIDDATA;
         }
+        ctx->tex_size += chunk->uncompressed_size;
+    }
+
+    av_log(avctx, AV_LOG_DEBUG, "%s compressor\n", compressorstr);
+
+    return ret;
+}
+
+static int decompress_chunks_thread(AVCodecContext *avctx, void *arg,
+                                    int chunk_nb, int thread_nb)
+{
+    HapContext *ctx = avctx->priv_data;
+
+    HapChunk *chunk = &ctx->chunks[chunk_nb];
+    GetByteContext gbc;
+    uint8_t *dst = ctx->tex_buf + chunk->uncompressed_offset;
+
+    bytestream2_init(&gbc, ctx->gbc.buffer + chunk->compressed_offset, chunk->compressed_size);
+
+    if (chunk->compressor == HAP_COMP_SNAPPY) {
+        int ret;
+        int64_t uncompressed_size = ctx->tex_size;
+
         /* Uncompress the frame */
-        ret = ff_snappy_uncompress(gbc, ctx->snappied, &snappy_size);
+        ret = ff_snappy_uncompress(&gbc, dst, &uncompressed_size);
         if (ret < 0) {
              av_log(avctx, AV_LOG_ERROR, "Snappy uncompress error\n");
              return ret;
         }
-
-        ctx->tex_data = ctx->snappied;
-        ctx->tex_size = snappy_size;
-        compressorstr = "snappy";
-        break;
-    case HAP_COMP_COMPLEX:
-        compressorstr = "complex";
-        avpriv_request_sample(avctx, "Complex Hap compressor");
-        return AVERROR_PATCHWELCOME;
-        break;
-    default:
-        av_log(avctx, AV_LOG_ERROR,
-               "Invalid compressor mode %02X.\n", ctx->section_type);
-        return AVERROR_INVALIDDATA;
+    } else if (chunk->compressor == HAP_COMP_NONE) {
+        bytestream2_get_buffer(&gbc, dst, chunk->compressed_size);
     }
 
-    av_log(avctx, AV_LOG_DEBUG, "%s compressor\n", compressorstr);
-
     return 0;
 }
 
@@ -167,19 +308,12 @@ static int hap_decode(AVCodecContext *avctx, void *data,
 {
     HapContext *ctx = avctx->priv_data;
     ThreadFrame tframe;
-    int ret, length;
+    int ret, i;
 
     bytestream2_init(&ctx->gbc, avpkt->data, avpkt->size);
 
     /* Check for section header */
-    length = parse_section_header(avctx);
-    if (length < 0) {
-        av_log(avctx, AV_LOG_ERROR, "Frame is too small.\n");
-        return length;
-    }
-
-    /* Prepare the texture buffer and decompress function */
-    ret = setup_texture(avctx, length);
+    ret = hap_parse_frame_header(avctx);
     if (ret < 0)
         return ret;
 
@@ -190,6 +324,27 @@ static int hap_decode(AVCodecContext *avctx, void *data,
         return ret;
     ff_thread_finish_setup(avctx);
 
+    /* Unpack the DXT texture */
+    if (hap_can_use_tex_in_place(ctx)) {
+        /* Only DXTC texture compression in a contiguous block */
+        ctx->tex_data = ctx->gbc.buffer;
+    } else {
+        /* Perform the second-stage decompression */
+        ret = av_reallocp(&ctx->tex_buf, ctx->tex_size);
+        if (ret < 0)
+            return ret;
+
+        avctx->execute2(avctx, decompress_chunks_thread, NULL,
+                        ctx->chunk_results, ctx->chunk_count);
+
+        for (i = 0; i < ctx->chunk_count; i++) {
+            if (ctx->chunk_results[i] < 0)
+                return ctx->chunk_results[i];
+        }
+
+        ctx->tex_data = ctx->tex_buf;
+    }
+
     /* Use the decompress function on the texture, one block per thread */
     avctx->execute2(avctx, decompress_texture_thread, tframe.f, NULL, ctx->slice_count);
 
@@ -254,7 +409,7 @@ static av_cold int hap_close(AVCodecContext *avctx)
 {
     HapContext *ctx = avctx->priv_data;
 
-    av_freep(&ctx->snappied);
+    ff_hap_free_context(ctx);
 
     return 0;
 }
diff --git a/libavcodec/hapenc.c b/libavcodec/hapenc.c
index d828a096d5..4a31447c9e 100644
--- a/libavcodec/hapenc.c
+++ b/libavcodec/hapenc.c
@@ -1,6 +1,7 @@
 /*
  * Vidvox Hap encoder
  * Copyright (C) 2015 Vittorio Giovara <vittorio.giovara@gmail.com>
+ * Copyright (C) 2015 Tom Butterworth <bangnoise@gmail.com>
  *
  * This file is part of Libav.
  *
@@ -42,8 +43,14 @@
 #include "internal.h"
 #include "texturedsp.h"
 
-/* A fixed header size allows to skip a memcpy */
-#define HEADER_SIZE 8
+#define HAP_MAX_CHUNKS 64
+
+enum HapHeaderLength {
+    /* Short header: four bytes with a 24 bit size value */
+    HAP_HDR_SHORT = 4,
+    /* Long header: eight bytes with a 32 bit size value */
+    HAP_HDR_LONG = 8,
+};
 
 static void compress_texture(AVCodecContext *avctx, const AVFrame *f)
 {
@@ -60,13 +67,133 @@ static void compress_texture(AVCodecContext *avctx, const AVFrame *f)
     }
 }
 
+/* section_length does not include the header */
+static void hap_write_section_header(PutByteContext *pbc,
+                                     enum HapHeaderLength header_length,
+                                     int section_length,
+                                     enum HapSectionType section_type)
+{
+    /* The first three bytes are the length of the section (not including the
+     * header) or zero if using an eight-byte header.
+     * For an eight-byte header, the length is in the last four bytes.
+     * The fourth byte stores the section type. */
+    bytestream2_put_le24(pbc, header_length == HAP_HDR_LONG ? 0 : section_length);
+    bytestream2_put_byte(pbc, section_type);
+
+    if (header_length == HAP_HDR_LONG) {
+        bytestream2_put_le32(pbc, section_length);
+    }
+}
+
+static int hap_compress_frame(AVCodecContext *avctx, uint8_t *dst)
+{
+    HapContext *ctx = avctx->priv_data;
+    int i, final_size = 0;
+
+    for (i = 0; i < ctx->chunk_count; i++) {
+        HapChunk *chunk = &ctx->chunks[i];
+        uint8_t *chunk_src, *chunk_dst;
+        int ret;
+
+        if (i == 0) {
+            chunk->compressed_offset = 0;
+        } else {
+            chunk->compressed_offset = ctx->chunks[i-1].compressed_offset
+                                       + ctx->chunks[i-1].compressed_size;
+        }
+        chunk->uncompressed_size = ctx->tex_size / ctx->chunk_count;
+        chunk->uncompressed_offset = i * chunk->uncompressed_size;
+        chunk->compressed_size = ctx->max_snappy;
+        chunk_src = ctx->tex_buf + chunk->uncompressed_offset;
+        chunk_dst = dst + chunk->compressed_offset;
+
+        /* Compress with snappy too, write directly on packet buffer. */
+        ret = snappy_compress(chunk_src, chunk->uncompressed_size,
+                              chunk_dst, &chunk->compressed_size);
+        if (ret != SNAPPY_OK) {
+            av_log(avctx, AV_LOG_ERROR, "Snappy compress error.\n");
+            return AVERROR_BUG;
+        }
+
+        /* If there is no gain from snappy, just use the raw texture. */
+        if (chunk->compressed_size >= chunk->uncompressed_size) {
+            av_log(avctx, AV_LOG_VERBOSE,
+                   "Snappy buffer bigger than uncompressed (%lu >= %lu bytes).\n",
+                   chunk->compressed_size, chunk->uncompressed_size);
+            memcpy(chunk_dst, chunk_src, chunk->uncompressed_size);
+            chunk->compressor = HAP_COMP_NONE;
+            chunk->compressed_size = chunk->uncompressed_size;
+        } else {
+            chunk->compressor = HAP_COMP_SNAPPY;
+        }
+
+        final_size += chunk->compressed_size;
+    }
+
+    return final_size;
+}
+
+static int hap_decode_instructions_length(HapContext *ctx)
+{
+    /*    Second-Stage Compressor Table (one byte per entry)
+     *  + Chunk Size Table (four bytes per entry)
+     *  + headers for both sections (short versions)
+     *  = chunk_count + (4 * chunk_count) + 4 + 4 */
+    return (5 * ctx->chunk_count) + 8;
+}
+
+static int hap_header_length(HapContext *ctx)
+{
+    /* Top section header (long version) */
+    int length = HAP_HDR_LONG;
+
+    if (ctx->chunk_count > 1) {
+        /* Decode Instructions header (short) + Decode Instructions Container */
+        length += HAP_HDR_SHORT + hap_decode_instructions_length(ctx);
+    }
+
+    return length;
+}
+
+static void hap_write_frame_header(HapContext *ctx, uint8_t *dst, int frame_length)
+{
+    PutByteContext pbc;
+    int i;
+
+    bytestream2_init_writer(&pbc, dst, frame_length);
+    if (ctx->chunk_count == 1) {
+        /* Write a simple header */
+        hap_write_section_header(&pbc, HAP_HDR_LONG, frame_length - 8,
+                                 ctx->chunks[0].compressor | ctx->opt_tex_fmt);
+    } else {
+        /* Write a complex header with Decode Instructions Container */
+        hap_write_section_header(&pbc, HAP_HDR_LONG, frame_length - 8,
+                                 HAP_COMP_COMPLEX | ctx->opt_tex_fmt);
+        hap_write_section_header(&pbc, HAP_HDR_SHORT, hap_decode_instructions_length(ctx),
+                                 HAP_ST_DECODE_INSTRUCTIONS);
+        hap_write_section_header(&pbc, HAP_HDR_SHORT, ctx->chunk_count,
+                                 HAP_ST_COMPRESSOR_TABLE);
+
+        for (i = 0; i < ctx->chunk_count; i++) {
+            bytestream2_put_byte(&pbc, ctx->chunks[i].compressor >> 4);
+        }
+
+        hap_write_section_header(&pbc, HAP_HDR_SHORT, ctx->chunk_count * 4,
+                                 HAP_ST_SIZE_TABLE);
+
+        for (i = 0; i < ctx->chunk_count; i++) {
+            bytestream2_put_le32(&pbc, ctx->chunks[i].compressed_size);
+        }
+    }
+}
+
 static int hap_encode(AVCodecContext *avctx, AVPacket *pkt,
                       const AVFrame *frame, int *got_packet)
 {
     HapContext *ctx = avctx->priv_data;
-    size_t final_size = ctx->max_snappy;
-    int ret, comp = HAP_COMP_SNAPPY;
-    int pktsize = FFMAX(ctx->tex_size, ctx->max_snappy) + HEADER_SIZE;
+    int header_length = hap_header_length(ctx);
+    int final_data_size, ret;
+    int pktsize = FFMAX(ctx->tex_size, ctx->max_snappy * ctx->chunk_count) + header_length;
 
     /* Allocate maximum size packet, shrink later. */
     ret = ff_alloc_packet(pkt, pktsize);
@@ -76,30 +203,15 @@ static int hap_encode(AVCodecContext *avctx, AVPacket *pkt,
     /* DXTC compression. */
     compress_texture(avctx, frame);
 
-    /* Compress with snappy too, write directly on packet buffer. */
-    ret = snappy_compress(ctx->tex_buf, ctx->tex_size,
-                          pkt->data + HEADER_SIZE, &final_size);
-    if (ret != SNAPPY_OK) {
-        av_log(avctx, AV_LOG_ERROR, "Snappy compress error.\n");
-        return AVERROR_BUG;
-    }
-
-    /* If there is no gain from snappy, just use the raw texture. */
-    if (final_size > ctx->tex_size) {
-        comp = HAP_COMP_NONE;
-        av_log(avctx, AV_LOG_VERBOSE,
-               "Snappy buffer bigger than uncompressed (%lu > %lu bytes).\n",
-               final_size, ctx->tex_size);
-        memcpy(pkt->data + HEADER_SIZE, ctx->tex_buf, ctx->tex_size);
-        final_size = ctx->tex_size;
-    }
+    /* Compress (using Snappy) the frame */
+    final_data_size = hap_compress_frame(avctx, pkt->data + header_length);
+    if (final_data_size < 0)
+        return final_data_size;
 
     /* Write header at the start. */
-    AV_WL24(pkt->data, 0);
-    AV_WL32(pkt->data + 4, final_size);
-    pkt->data[3] = comp | ctx->section_type;
+    hap_write_frame_header(ctx, pkt->data, final_data_size + header_length);
 
-    av_shrink_packet(pkt, final_size + HEADER_SIZE);
+    av_shrink_packet(pkt, final_data_size + header_length);
     pkt->flags |= AV_PKT_FLAG_KEY;
     *got_packet = 1;
     return 0;
@@ -109,6 +221,7 @@ static av_cold int hap_init(AVCodecContext *avctx)
 {
     HapContext *ctx = avctx->priv_data;
     int ratio;
+    int corrected_chunk_count;
     int ret = av_image_check_size(avctx->width, avctx->height, 0, avctx);
 
     if (ret < 0) {
@@ -125,7 +238,7 @@ static av_cold int hap_init(AVCodecContext *avctx)
 
     ff_texturedspenc_init(&ctx->dxtc);
 
-    switch (ctx->section_type & 0x0F) {
+    switch (ctx->opt_tex_fmt) {
     case HAP_FMT_RGBDXT1:
         ratio = 8;
         avctx->codec_tag = MKTAG('H', 'a', 'p', '1');
@@ -142,7 +255,7 @@ static av_cold int hap_init(AVCodecContext *avctx)
         ctx->tex_fun = ctx->dxtc.dxt5ys_block;
         break;
     default:
-        av_log(avctx, AV_LOG_ERROR, "Invalid format %02X\n", ctx->section_type);
+        av_log(avctx, AV_LOG_ERROR, "Invalid format %02X\n", ctx->opt_tex_fmt);
         return AVERROR_INVALIDDATA;
     }
 
@@ -150,7 +263,21 @@ static av_cold int hap_init(AVCodecContext *avctx)
      * beforehand the final size of the uncompressed buffer. */
     ctx->tex_size   = FFALIGN(avctx->width,  TEXTURE_BLOCK_W) *
                       FFALIGN(avctx->height, TEXTURE_BLOCK_H) * 4 / ratio;
-    ctx->max_snappy = snappy_max_compressed_length(ctx->tex_size);
+
+    /* Round the chunk count to divide evenly on DXT block edges */
+    corrected_chunk_count = av_clip(ctx->opt_chunk_count, 1, HAP_MAX_CHUNKS);
+    while ((ctx->tex_size / (64 / ratio)) % corrected_chunk_count != 0) {
+        corrected_chunk_count--;
+    }
+    if (corrected_chunk_count != ctx->opt_chunk_count) {
+        av_log(avctx, AV_LOG_INFO, "%d chunks requested but %d used.\n",
+                                    ctx->opt_chunk_count, corrected_chunk_count);
+    }
+    ret = ff_hap_set_chunk_count(ctx, corrected_chunk_count, 1);
+    if (ret != 0)
+        return ret;
+
+    ctx->max_snappy = snappy_max_compressed_length(ctx->tex_size / corrected_chunk_count);
 
     ctx->tex_buf  = av_malloc(ctx->tex_size);
     if (!ctx->tex_buf)
@@ -163,7 +290,7 @@ static av_cold int hap_close(AVCodecContext *avctx)
 {
     HapContext *ctx = avctx->priv_data;
 
-    av_freep(&ctx->tex_buf);
+    ff_hap_free_context(ctx);
 
     return 0;
 }
@@ -171,11 +298,11 @@ static av_cold int hap_close(AVCodecContext *avctx)
 #define OFFSET(x) offsetof(HapContext, x)
 #define FLAGS     AV_OPT_FLAG_VIDEO_PARAM | AV_OPT_FLAG_ENCODING_PARAM
 static const AVOption options[] = {
-    { "format", NULL, OFFSET(section_type), AV_OPT_TYPE_INT, { .i64 = HAP_FMT_RGBDXT1 }, HAP_FMT_RGBDXT1, HAP_FMT_YCOCGDXT5, FLAGS, "format" },
+    { "format", NULL, OFFSET(opt_tex_fmt), AV_OPT_TYPE_INT, { .i64 = HAP_FMT_RGBDXT1 }, HAP_FMT_RGBDXT1, HAP_FMT_YCOCGDXT5, FLAGS, "format" },
         { "hap",       "Hap 1 (DXT1 textures)", 0, AV_OPT_TYPE_CONST, { .i64 = HAP_FMT_RGBDXT1   }, 0, 0, FLAGS, "format" },
         { "hap_alpha", "Hap Alpha (DXT5 textures)", 0, AV_OPT_TYPE_CONST, { .i64 = HAP_FMT_RGBADXT5  }, 0, 0, FLAGS, "format" },
         { "hap_q",     "Hap Q (DXT5-YCoCg textures)", 0, AV_OPT_TYPE_CONST, { .i64 = HAP_FMT_YCOCGDXT5 }, 0, 0, FLAGS, "format" },
-
+    { "chunks", "chunk count", OFFSET(opt_chunk_count), AV_OPT_TYPE_INT, {.i64 = 1 }, 1, HAP_MAX_CHUNKS, FLAGS, },
     { NULL },
 };
 
diff --git a/libavcodec/version.h b/libavcodec/version.h
index f8e5ac8865..94cc77576c 100644
--- a/libavcodec/version.h
+++ b/libavcodec/version.h
@@ -30,7 +30,7 @@
 
 #define LIBAVCODEC_VERSION_MAJOR 56
 #define LIBAVCODEC_VERSION_MINOR 35
-#define LIBAVCODEC_VERSION_MICRO  0
+#define LIBAVCODEC_VERSION_MICRO  1
 
 #define LIBAVCODEC_VERSION_INT  AV_VERSION_INT(LIBAVCODEC_VERSION_MAJOR, \
                                                LIBAVCODEC_VERSION_MINOR, \
diff --git a/tests/fate/video.mak b/tests/fate/video.mak
index f1d8f2a9c6..77cc9e7c6a 100644
--- a/tests/fate/video.mak
+++ b/tests/fate/video.mak
@@ -169,6 +169,9 @@ fate-hap5: CMD = framecrc -i $(TARGET_SAMPLES)/hap/hap5.mov
 FATE_HAP += fate-hapy
 fate-hapy: CMD = framecrc -i $(TARGET_SAMPLES)/hap/hapy.mov
 
+FATE_HAP += fate-hap-chunk
+fate-hap-chunk: CMD = framecrc -i $(TARGET_SAMPLES)/hap/hapy-12-chunks.mov
+
 FATE_SAMPLES_AVCONV-$(call DEMDEC, MOV, HAP) += $(FATE_HAP)
 fate-hap: $(FATE_HAP)