libavcodec/hapenc.c

   1 /*
   2  * Vidvox Hap encoder
   3  * Copyright (C) 2015 Vittorio Giovara <vittorio.giovara@gmail.com>
   4  * Copyright (C) 2015 Tom Butterworth <bangnoise@gmail.com>
   5  *
   6  * This file is part of Libav.
   7  *
   8  * Libav is free software; you can redistribute it and/or
   9  * modify it under the terms of the GNU Lesser General Public
  10  * License as published by the Free Software Foundation; either
  11  * version 2.1 of the License, or (at your option) any later version.
  12  *
  13  * Libav is distributed in the hope that it will be useful,
  14  * but WITHOUT ANY WARRANTY; without even the implied warranty of
  15  * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
  16  * Lesser General Public License for more details.
  17  *
  18  * You should have received a copy of the GNU Lesser General Public
  19  * License along with Libav; if not, write to the Free Software
  20  * Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA
  21  */
  22
  23 /**
  24  * @file
  25  * Hap encoder
  26  *
  27  * Fourcc: Hap1, Hap5, HapY
  28  *
  29  * https://github.com/Vidvox/hap/blob/master/documentation/HapVideoDRAFT.md
  30  */
  31
  32 #include <stdint.h>
  33 #include "snappy-c.h"
  34
  35 #include "libavutil/frame.h"
  36 #include "libavutil/imgutils.h"
  37 #include "libavutil/intreadwrite.h"
  38 #include "libavutil/opt.h"
  39
  40 #include "avcodec.h"
  41 #include "bytestream.h"
  42 #include "hap.h"
  43 #include "internal.h"
  44 #include "texturedsp.h"
  45
  46 #define HAP_MAX_CHUNKS 64
  47
  48 enum HapHeaderLength {
  49     /* Short header: four bytes with a 24 bit size value */
  50     HAP_HDR_SHORT = 4,
  51     /* Long header: eight bytes with a 32 bit size value */
  52     HAP_HDR_LONG = 8,
  53 };
  54
  55 static void compress_texture(AVCodecContext *avctx, const AVFrame *f)
  56 {
  57     HapContext *ctx = avctx->priv_data;
  58     uint8_t *out = ctx->tex_buf;
  59     int i, j;
  60
  61     for (j = 0; j < avctx->height; j += 4) {
  62         for (i = 0; i < avctx->width; i += 4) {
  63             uint8_t *p = f->data[0] + i * 4 + j * f->linesize[0];
  64             const int step = ctx->tex_fun(out, f->linesize[0], p);
  65             out += step;
  66         }
  67     }
  68 }
  69
  70 /* section_length does not include the header */
  71 static void hap_write_section_header(PutByteContext *pbc,
  72                                      enum HapHeaderLength header_length,
  73                                      int section_length,
  74                                      enum HapSectionType section_type)
  75 {
  76     /* The first three bytes are the length of the section (not including the
  77      * header) or zero if using an eight-byte header.
  78      * For an eight-byte header, the length is in the last four bytes.
  79      * The fourth byte stores the section type. */
  80     bytestream2_put_le24(pbc, header_length == HAP_HDR_LONG ? 0 : section_length);
  81     bytestream2_put_byte(pbc, section_type);
  82
  83     if (header_length == HAP_HDR_LONG) {
  84         bytestream2_put_le32(pbc, section_length);
  85     }
  86 }
  87
  88 static int hap_compress_frame(AVCodecContext *avctx, uint8_t *dst)
  89 {
  90     HapContext *ctx = avctx->priv_data;
  91     int i, final_size = 0;
  92
  93     for (i = 0; i < ctx->chunk_count; i++) {
  94         HapChunk *chunk = &ctx->chunks[i];
  95         uint8_t *chunk_src, *chunk_dst;
  96         int ret;
  97
  98         if (i == 0) {
  99             chunk->compressed_offset = 0;
 100         } else {
 101             chunk->compressed_offset = ctx->chunks[i-1].compressed_offset
 102                                        + ctx->chunks[i-1].compressed_size;
 103         }
 104         chunk->uncompressed_size = ctx->tex_size / ctx->chunk_count;
 105         chunk->uncompressed_offset = i * chunk->uncompressed_size;
 106         chunk->compressed_size = ctx->max_snappy;
 107         chunk_src = ctx->tex_buf + chunk->uncompressed_offset;
 108         chunk_dst = dst + chunk->compressed_offset;
 109
 110         /* Compress with snappy too, write directly on packet buffer. */
 111         ret = snappy_compress(chunk_src, chunk->uncompressed_size,
 112                               chunk_dst, &chunk->compressed_size);
 113         if (ret != SNAPPY_OK) {
 114             av_log(avctx, AV_LOG_ERROR, "Snappy compress error.\n");
 115             return AVERROR_BUG;
 116         }
 117
 118         /* If there is no gain from snappy, just use the raw texture. */
 119         if (chunk->compressed_size >= chunk->uncompressed_size) {
 120             av_log(avctx, AV_LOG_VERBOSE,
 121                    "Snappy buffer bigger than uncompressed (%zu >= %zu bytes).\n",
 122                    chunk->compressed_size, chunk->uncompressed_size);
 123             memcpy(chunk_dst, chunk_src, chunk->uncompressed_size);
 124             chunk->compressor = HAP_COMP_NONE;
 125             chunk->compressed_size = chunk->uncompressed_size;
 126         } else {
 127             chunk->compressor = HAP_COMP_SNAPPY;
 128         }
 129
 130         final_size += chunk->compressed_size;
 131     }
 132
 133     return final_size;
 134 }
 135
 136 static int hap_decode_instructions_length(HapContext *ctx)
 137 {
 138     /*    Second-Stage Compressor Table (one byte per entry)
 139      *  + Chunk Size Table (four bytes per entry)
 140      *  + headers for both sections (short versions)
 141      *  = chunk_count + (4 * chunk_count) + 4 + 4 */
 142     return (5 * ctx->chunk_count) + 8;
 143 }
 144
 145 static int hap_header_length(HapContext *ctx)
 146 {
 147     /* Top section header (long version) */
 148     int length = HAP_HDR_LONG;
 149
 150     if (ctx->chunk_count > 1) {
 151         /* Decode Instructions header (short) + Decode Instructions Container */
 152         length += HAP_HDR_SHORT + hap_decode_instructions_length(ctx);
 153     }
 154
 155     return length;
 156 }
 157
 158 static void hap_write_frame_header(HapContext *ctx, uint8_t *dst, int frame_length)
 159 {
 160     PutByteContext pbc;
 161     int i;
 162
 163     bytestream2_init_writer(&pbc, dst, frame_length);
 164     if (ctx->chunk_count == 1) {
 165         /* Write a simple header */
 166         hap_write_section_header(&pbc, HAP_HDR_LONG, frame_length - 8,
 167                                  ctx->chunks[0].compressor | ctx->opt_tex_fmt);
 168     } else {
 169         /* Write a complex header with Decode Instructions Container */
 170         hap_write_section_header(&pbc, HAP_HDR_LONG, frame_length - 8,
 171                                  HAP_COMP_COMPLEX | ctx->opt_tex_fmt);
 172         hap_write_section_header(&pbc, HAP_HDR_SHORT, hap_decode_instructions_length(ctx),
 173                                  HAP_ST_DECODE_INSTRUCTIONS);
 174         hap_write_section_header(&pbc, HAP_HDR_SHORT, ctx->chunk_count,
 175                                  HAP_ST_COMPRESSOR_TABLE);
 176
 177         for (i = 0; i < ctx->chunk_count; i++) {
 178             bytestream2_put_byte(&pbc, ctx->chunks[i].compressor >> 4);
 179         }
 180
 181         hap_write_section_header(&pbc, HAP_HDR_SHORT, ctx->chunk_count * 4,
 182                                  HAP_ST_SIZE_TABLE);
 183
 184         for (i = 0; i < ctx->chunk_count; i++) {
 185             bytestream2_put_le32(&pbc, ctx->chunks[i].compressed_size);
 186         }
 187     }
 188 }
 189
 190 static int hap_encode(AVCodecContext *avctx, AVPacket *pkt,
 191                       const AVFrame *frame, int *got_packet)
 192 {
 193     HapContext *ctx = avctx->priv_data;
 194     int header_length = hap_header_length(ctx);
 195     int final_data_size, ret;
 196     int pktsize = FFMAX(ctx->tex_size, ctx->max_snappy * ctx->chunk_count) + header_length;
 197
 198     /* Allocate maximum size packet, shrink later. */
 199     ret = ff_alloc_packet(pkt, pktsize);
 200     if (ret < 0)
 201         return ret;
 202
 203     /* DXTC compression. */
 204     compress_texture(avctx, frame);
 205
 206     /* Compress (using Snappy) the frame */
 207     final_data_size = hap_compress_frame(avctx, pkt->data + header_length);
 208     if (final_data_size < 0)
 209         return final_data_size;
 210
 211     /* Write header at the start. */
 212     hap_write_frame_header(ctx, pkt->data, final_data_size + header_length);
 213
 214     av_shrink_packet(pkt, final_data_size + header_length);
 215     pkt->flags |= AV_PKT_FLAG_KEY;
 216     *got_packet = 1;
 217     return 0;
 218 }
 219
 220 static av_cold int hap_init(AVCodecContext *avctx)
 221 {
 222     HapContext *ctx = avctx->priv_data;
 223     int ratio;
 224     int corrected_chunk_count;
 225     int ret = av_image_check_size(avctx->width, avctx->height, 0, avctx);
 226
 227     if (ret < 0) {
 228         av_log(avctx, AV_LOG_ERROR, "Invalid video size %dx%d.\n",
 229                avctx->width, avctx->height);
 230         return ret;
 231     }
 232
 233     if (avctx->width % 4 || avctx->height % 4) {
 234         av_log(avctx, AV_LOG_ERROR, "Video size %dx%d is not multiple of 4.\n",
 235                avctx->width, avctx->height);
 236         return AVERROR_INVALIDDATA;
 237     }
 238
 239     ff_texturedspenc_init(&ctx->dxtc);
 240
 241     switch (ctx->opt_tex_fmt) {
 242     case HAP_FMT_RGBDXT1:
 243         ratio = 8;
 244         avctx->codec_tag = MKTAG('H', 'a', 'p', '1');
 245         avctx->bits_per_coded_sample = 24;
 246         ctx->tex_fun = ctx->dxtc.dxt1_block;
 247         break;
 248     case HAP_FMT_RGBADXT5:
 249         ratio = 4;
 250         avctx->codec_tag = MKTAG('H', 'a', 'p', '5');
 251         avctx->bits_per_coded_sample = 32;
 252         ctx->tex_fun = ctx->dxtc.dxt5_block;
 253         break;
 254     case HAP_FMT_YCOCGDXT5:
 255         ratio = 4;
 256         avctx->codec_tag = MKTAG('H', 'a', 'p', 'Y');
 257         avctx->bits_per_coded_sample = 24;
 258         ctx->tex_fun = ctx->dxtc.dxt5ys_block;
 259         break;
 260     default:
 261         av_log(avctx, AV_LOG_ERROR, "Invalid format %02X\n", ctx->opt_tex_fmt);
 262         return AVERROR_INVALIDDATA;
 263     }
 264
 265     /* Texture compression ratio is constant, so can we computer
 266      * beforehand the final size of the uncompressed buffer. */
 267     ctx->tex_size   = FFALIGN(avctx->width,  TEXTURE_BLOCK_W) *
 268                       FFALIGN(avctx->height, TEXTURE_BLOCK_H) * 4 / ratio;
 269
 270     /* Round the chunk count to divide evenly on DXT block edges */
 271     corrected_chunk_count = av_clip(ctx->opt_chunk_count, 1, HAP_MAX_CHUNKS);
 272     while ((ctx->tex_size / (64 / ratio)) % corrected_chunk_count != 0) {
 273         corrected_chunk_count--;
 274     }
 275     if (corrected_chunk_count != ctx->opt_chunk_count) {
 276         av_log(avctx, AV_LOG_INFO, "%d chunks requested but %d used.\n",
 277                                     ctx->opt_chunk_count, corrected_chunk_count);
 278     }
 279     ret = ff_hap_set_chunk_count(ctx, corrected_chunk_count, 1);
 280     if (ret != 0)
 281         return ret;
 282
 283     ctx->max_snappy = snappy_max_compressed_length(ctx->tex_size / corrected_chunk_count);
 284
 285     ctx->tex_buf  = av_malloc(ctx->tex_size);
 286     if (!ctx->tex_buf)
 287         return AVERROR(ENOMEM);
 288
 289     return 0;
 290 }
 291
 292 static av_cold int hap_close(AVCodecContext *avctx)
 293 {
 294     HapContext *ctx = avctx->priv_data;
 295
 296     ff_hap_free_context(ctx);
 297
 298     return 0;
 299 }
 300
 301 #define OFFSET(x) offsetof(HapContext, x)
 302 #define FLAGS     AV_OPT_FLAG_VIDEO_PARAM | AV_OPT_FLAG_ENCODING_PARAM
 303 static const AVOption options[] = {
 304     { "format", NULL, OFFSET(opt_tex_fmt), AV_OPT_TYPE_INT, { .i64 = HAP_FMT_RGBDXT1 }, HAP_FMT_RGBDXT1, HAP_FMT_YCOCGDXT5, FLAGS, "format" },
 305         { "hap",       "Hap 1 (DXT1 textures)", 0, AV_OPT_TYPE_CONST, { .i64 = HAP_FMT_RGBDXT1   }, 0, 0, FLAGS, "format" },
 306         { "hap_alpha", "Hap Alpha (DXT5 textures)", 0, AV_OPT_TYPE_CONST, { .i64 = HAP_FMT_RGBADXT5  }, 0, 0, FLAGS, "format" },
 307         { "hap_q",     "Hap Q (DXT5-YCoCg textures)", 0, AV_OPT_TYPE_CONST, { .i64 = HAP_FMT_YCOCGDXT5 }, 0, 0, FLAGS, "format" },
 308     { "chunks", "chunk count", OFFSET(opt_chunk_count), AV_OPT_TYPE_INT, {.i64 = 1 }, 1, HAP_MAX_CHUNKS, FLAGS, },
 309     { NULL },
 310 };
 311
 312 static const AVClass hapenc_class = {
 313     .class_name = "Hap encoder",
 314     .item_name  = av_default_item_name,
 315     .option     = options,
 316     .version    = LIBAVUTIL_VERSION_INT,
 317 };
 318
 319 AVCodec ff_hap_encoder = {
 320     .name           = "hap",
 321     .long_name      = NULL_IF_CONFIG_SMALL("Vidvox Hap encoder"),
 322     .type           = AVMEDIA_TYPE_VIDEO,
 323     .id             = AV_CODEC_ID_HAP,
 324     .priv_data_size = sizeof(HapContext),
 325     .priv_class     = &hapenc_class,
 326     .init           = hap_init,
 327     .encode2        = hap_encode,
 328     .close          = hap_close,
 329     .pix_fmts       = (const enum AVPixelFormat[]) {
 330         AV_PIX_FMT_RGBA, AV_PIX_FMT_NONE,
 331     },
 332     .caps_internal  = FF_CODEC_CAP_INIT_THREADSAFE |
 333                       FF_CODEC_CAP_INIT_CLEANUP,
 334 };