libavcodec/hq_hqa.c - third_party/ffmpeg - Git at Google

 /*
  * Canopus HQ/HQA decoder
  *
  * This file is part of FFmpeg.
  *
  * FFmpeg is free software; you can redistribute it and/or
  * modify it under the terms of the GNU Lesser General Public
  * License as published by the Free Software Foundation; either
  * version 2.1 of the License, or (at your option) any later version.
  *
  * FFmpeg is distributed in the hope that it will be useful,
  * but WITHOUT ANY WARRANTY; without even the implied warranty of
  * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
  * Lesser General Public License for more details.
  *
  * You should have received a copy of the GNU Lesser General Public
  * License along with FFmpeg; if not, write to the Free Software
  * Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA
  */

 #include <stdint.h>

 #include "libavutil/attributes.h"
 #include "libavutil/intreadwrite.h"

 #include "avcodec.h"
 #include "canopus.h"
 #include "get_bits.h"
 #include "internal.h"

 #include "hq_hqa.h"
 #include "hq_hqadsp.h"

 /* HQ/HQA slices are a set of macroblocks belonging to a frame, and
  * they usually form a pseudorandom pattern (probably because it is
  * nicer to display on partial decode).
  *
  * For HQA it just happens that each slice is on every 8th macroblock,
  * but they can be on any frame width like
  *   X.......X.
  *   ......X...
  *   ....X.....
  *   ..X.......
  * etc.
  *
  * The original decoder has special handling for edge macroblocks,
  * while lavc simply aligns coded_width and coded_height.
  */

 static inline void put_blocks(HQContext *c, AVFrame *pic,
                               int plane, int x, int y, int ilace,
                               int16_t *block0, int16_t *block1)
 {
     uint8_t *p = pic->data[plane] + x;

     c->hqhqadsp.idct_put(p + y * pic->linesize[plane],
                          pic->linesize[plane] << ilace, block0);
     c->hqhqadsp.idct_put(p + (y + (ilace ? 1 : 8)) * pic->linesize[plane],
                          pic->linesize[plane] << ilace, block1);
 }

 static int hq_decode_block(HQContext *c, GetBitContext *gb, int16_t block[64],
                            int qsel, int is_chroma, int is_hqa)
 {
     const int32_t *q;
     int val, pos = 1;

     memset(block, 0, 64 * sizeof(*block));

     if (!is_hqa) {
         block[0] = get_sbits(gb, 9) * 64;
         q = ff_hq_quants[qsel][is_chroma][get_bits(gb, 2)];
     } else {
         q = ff_hq_quants[qsel][is_chroma][get_bits(gb, 2)];
         block[0] = get_sbits(gb, 9) * 64;
     }

     for (;;) {
         val = get_vlc2(gb, c->hq_ac_vlc.table, 9, 2);
         if (val < 0)
             return AVERROR_INVALIDDATA;

         pos += ff_hq_ac_skips[val];
         if (pos >= 64)
             break;
         block[ff_zigzag_direct[pos]] = (int)(ff_hq_ac_syms[val] * (unsigned)q[pos]) >> 12;
         pos++;
     }

     return 0;
 }

 static int hq_decode_mb(HQContext *c, AVFrame *pic,
                         GetBitContext *gb, int x, int y)
 {
     int qgroup, flag;
     int i, ret;

     qgroup = get_bits(gb, 4);
     flag = get_bits1(gb);

     for (i = 0; i < 8; i++) {
         ret = hq_decode_block(c, gb, c->block[i], qgroup, i >= 4, 0);
         if (ret < 0)
             return ret;
     }

     put_blocks(c, pic, 0, x,      y, flag, c->block[0], c->block[2]);
     put_blocks(c, pic, 0, x + 8,  y, flag, c->block[1], c->block[3]);
     put_blocks(c, pic, 2, x >> 1, y, flag, c->block[4], c->block[5]);
     put_blocks(c, pic, 1, x >> 1, y, flag, c->block[6], c->block[7]);

     return 0;
 }

 static int hq_decode_frame(HQContext *ctx, AVFrame *pic,
                            int prof_num, size_t data_size)
 {
     const HQProfile *profile;
     GetBitContext gb;
     const uint8_t *perm, *src = ctx->gbc.buffer;
     uint32_t slice_off[21];
     int slice, start_off, next_off, i, ret;

     if ((unsigned)prof_num >= NUM_HQ_PROFILES) {
         profile = &ff_hq_profile[0];
         avpriv_request_sample(ctx->avctx, "HQ Profile %d", prof_num);
     } else {
         profile = &ff_hq_profile[prof_num];
         av_log(ctx->avctx, AV_LOG_VERBOSE, "HQ Profile %d\n", prof_num);
     }

     ctx->avctx->coded_width         = FFALIGN(profile->width,  16);
     ctx->avctx->coded_height        = FFALIGN(profile->height, 16);
     ctx->avctx->width               = profile->width;
     ctx->avctx->height              = profile->height;
     ctx->avctx->bits_per_raw_sample = 8;
     ctx->avctx->pix_fmt             = AV_PIX_FMT_YUV422P;

     ret = ff_get_buffer(ctx->avctx, pic, 0);
     if (ret < 0)
         return ret;

     /* Offsets are stored from CUV position, so adjust them accordingly. */
     for (i = 0; i < profile->num_slices + 1; i++)
         slice_off[i] = bytestream2_get_be24(&ctx->gbc) - 4;

     next_off = 0;
     for (slice = 0; slice < profile->num_slices; slice++) {
         start_off = next_off;
         next_off  = profile->tab_h * (slice + 1) / profile->num_slices;
         perm = profile->perm_tab + start_off * profile->tab_w * 2;

         if (slice_off[slice] < (profile->num_slices + 1) * 3 ||
             slice_off[slice] >= slice_off[slice + 1] ||
             slice_off[slice + 1] > data_size) {
             av_log(ctx->avctx, AV_LOG_ERROR,
                    "Invalid slice size %"SIZE_SPECIFIER".\n", data_size);
             break;
         }
         init_get_bits(&gb, src + slice_off[slice],
                       (slice_off[slice + 1] - slice_off[slice]) * 8);

         for (i = 0; i < (next_off - start_off) * profile->tab_w; i++) {
             ret = hq_decode_mb(ctx, pic, &gb, perm[0] * 16, perm[1] * 16);
             if (ret < 0) {
                 av_log(ctx->avctx, AV_LOG_ERROR,
                        "Error decoding macroblock %d at slice %d.\n", i, slice);
                 return ret;
             }
             perm += 2;
         }
     }

     return 0;
 }

 static int hqa_decode_mb(HQContext *c, AVFrame *pic, int qgroup,
                          GetBitContext *gb, int x, int y)
 {
     int flag = 0;
     int i, ret, cbp;

     cbp = get_vlc2(gb, c->hqa_cbp_vlc.table, 5, 1);

     for (i = 0; i < 12; i++)
         memset(c->block[i], 0, sizeof(*c->block));
     for (i = 0; i < 12; i++)
         c->block[i][0] = -128 * (1 << 6);

     if (cbp) {
         flag = get_bits1(gb);

         cbp |= cbp << 4;
         if (cbp & 0x3)
             cbp |= 0x500;
         if (cbp & 0xC)
             cbp |= 0xA00;
         for (i = 0; i < 12; i++) {
             if (!(cbp & (1 << i)))
                 continue;
             ret = hq_decode_block(c, gb, c->block[i], qgroup, i >= 8, 1);
             if (ret < 0)
                 return ret;
         }
     }

     put_blocks(c, pic, 3, x,      y, flag, c->block[ 0], c->block[ 2]);
     put_blocks(c, pic, 3, x + 8,  y, flag, c->block[ 1], c->block[ 3]);
     put_blocks(c, pic, 0, x,      y, flag, c->block[ 4], c->block[ 6]);
     put_blocks(c, pic, 0, x + 8,  y, flag, c->block[ 5], c->block[ 7]);
     put_blocks(c, pic, 2, x >> 1, y, flag, c->block[ 8], c->block[ 9]);
     put_blocks(c, pic, 1, x >> 1, y, flag, c->block[10], c->block[11]);

     return 0;
 }

 static int hqa_decode_slice(HQContext *ctx, AVFrame *pic, GetBitContext *gb,
                             int quant, int slice_no, int w, int h)
 {
     int i, j, off;
     int ret;

     for (i = 0; i < h; i += 16) {
         off = (slice_no * 16 + i * 3) & 0x70;
         for (j = off; j < w; j += 128) {
             ret = hqa_decode_mb(ctx, pic, quant, gb, j, i);
             if (ret < 0) {
                 av_log(ctx->avctx, AV_LOG_ERROR,
                        "Error decoding macroblock at %dx%d.\n", i, j);
                 return ret;
             }
         }
     }

     return 0;
 }

 static int hqa_decode_frame(HQContext *ctx, AVFrame *pic, size_t data_size)
 {
     GetBitContext gb;
     const int num_slices = 8;
     uint32_t slice_off[9];
     int i, slice, ret;
     int width, height, quant;
     const uint8_t *src = ctx->gbc.buffer;

     width  = bytestream2_get_be16(&ctx->gbc);
     height = bytestream2_get_be16(&ctx->gbc);

     ctx->avctx->coded_width         = FFALIGN(width,  16);
     ctx->avctx->coded_height        = FFALIGN(height, 16);
     ctx->avctx->width               = width;
     ctx->avctx->height              = height;
     ctx->avctx->bits_per_raw_sample = 8;
     ctx->avctx->pix_fmt             = AV_PIX_FMT_YUVA422P;

     av_log(ctx->avctx, AV_LOG_VERBOSE, "HQA Profile\n");

     quant = bytestream2_get_byte(&ctx->gbc);
     bytestream2_skip(&ctx->gbc, 3);
     if (quant >= NUM_HQ_QUANTS) {
         av_log(ctx->avctx, AV_LOG_ERROR,
                "Invalid quantization matrix %d.\n", quant);
         return AVERROR_INVALIDDATA;
     }

     ret = ff_get_buffer(ctx->avctx, pic, 0);
     if (ret < 0)
         return ret;

     /* Offsets are stored from HQA1 position, so adjust them accordingly. */
     for (i = 0; i < num_slices + 1; i++)
         slice_off[i] = bytestream2_get_be32(&ctx->gbc) - 4;

     for (slice = 0; slice < num_slices; slice++) {
         if (slice_off[slice] < (num_slices + 1) * 3 ||
             slice_off[slice] >= slice_off[slice + 1] ||
             slice_off[slice + 1] > data_size) {
             av_log(ctx->avctx, AV_LOG_ERROR,
                    "Invalid slice size %"SIZE_SPECIFIER".\n", data_size);
             break;
         }
         init_get_bits(&gb, src + slice_off[slice],
                       (slice_off[slice + 1] - slice_off[slice]) * 8);

         ret = hqa_decode_slice(ctx, pic, &gb, quant, slice, width, height);
         if (ret < 0)
             return ret;
     }

     return 0;
 }

 static int hq_hqa_decode_frame(AVCodecContext *avctx, void *data,
                                int *got_frame, AVPacket *avpkt)
 {
     HQContext *ctx = avctx->priv_data;
     AVFrame *pic = data;
     uint32_t info_tag;
     unsigned int data_size;
     int ret;
     unsigned tag;

     bytestream2_init(&ctx->gbc, avpkt->data, avpkt->size);
     if (bytestream2_get_bytes_left(&ctx->gbc) < 4 + 4) {
         av_log(avctx, AV_LOG_ERROR, "Frame is too small (%d).\n", avpkt->size);
         return AVERROR_INVALIDDATA;
     }

     info_tag = bytestream2_peek_le32(&ctx->gbc);
     if (info_tag == MKTAG('I', 'N', 'F', 'O')) {
         int info_size;
         bytestream2_skip(&ctx->gbc, 4);
         info_size = bytestream2_get_le32(&ctx->gbc);
         if (bytestream2_get_bytes_left(&ctx->gbc) < info_size) {
             av_log(avctx, AV_LOG_ERROR, "Invalid INFO size (%d).\n", info_size);
             return AVERROR_INVALIDDATA;
         }
         ff_canopus_parse_info_tag(avctx, ctx->gbc.buffer, info_size);

         bytestream2_skip(&ctx->gbc, info_size);
     }

     data_size = bytestream2_get_bytes_left(&ctx->gbc);
     if (data_size < 4) {
         av_log(avctx, AV_LOG_ERROR, "Frame is too small (%d).\n", data_size);
         return AVERROR_INVALIDDATA;
     }

     /* HQ defines dimensions and number of slices, and thus slice traversal
      * order. HQA has no size constraint and a fixed number of slices, so it
      * needs a separate scheme for it. */
     tag = bytestream2_get_le32(&ctx->gbc);
     if ((tag & 0x00FFFFFF) == (MKTAG('U', 'V', 'C', ' ') & 0x00FFFFFF)) {
         ret = hq_decode_frame(ctx, pic, tag >> 24, data_size);
     } else if (tag == MKTAG('H', 'Q', 'A', '1')) {
         ret = hqa_decode_frame(ctx, pic, data_size);
     } else {
         av_log(avctx, AV_LOG_ERROR, "Not a HQ/HQA frame.\n");
         return AVERROR_INVALIDDATA;
     }
     if (ret < 0) {
         av_log(avctx, AV_LOG_ERROR, "Error decoding frame.\n");
         return ret;
     }

     pic->key_frame = 1;
     pic->pict_type = AV_PICTURE_TYPE_I;

     *got_frame = 1;

     return avpkt->size;
 }

 static av_cold int hq_hqa_decode_init(AVCodecContext *avctx)
 {
     HQContext *ctx = avctx->priv_data;
     ctx->avctx = avctx;

     ff_hqdsp_init(&ctx->hqhqadsp);

     return ff_hq_init_vlcs(ctx);
 }

 static av_cold int hq_hqa_decode_close(AVCodecContext *avctx)
 {
     HQContext *ctx = avctx->priv_data;

     ff_free_vlc(&ctx->hq_ac_vlc);
     ff_free_vlc(&ctx->hqa_cbp_vlc);

     return 0;
 }

 AVCodec ff_hq_hqa_decoder = {
     .name           = "hq_hqa",
     .long_name      = NULL_IF_CONFIG_SMALL("Canopus HQ/HQA"),
     .type           = AVMEDIA_TYPE_VIDEO,
     .id             = AV_CODEC_ID_HQ_HQA,
     .priv_data_size = sizeof(HQContext),
     .init           = hq_hqa_decode_init,
     .decode         = hq_hqa_decode_frame,
     .close          = hq_hqa_decode_close,
     .capabilities   = AV_CODEC_CAP_DR1,
     .caps_internal  = FF_CODEC_CAP_INIT_THREADSAFE |
                       FF_CODEC_CAP_INIT_CLEANUP,
 };
	/*
	* Canopus HQ/HQA decoder
	*
	* This file is part of FFmpeg.
	*
	* FFmpeg is free software; you can redistribute it and/or
	* modify it under the terms of the GNU Lesser General Public
	* License as published by the Free Software Foundation; either
	* version 2.1 of the License, or (at your option) any later version.
	*
	* FFmpeg is distributed in the hope that it will be useful,
	* but WITHOUT ANY WARRANTY; without even the implied warranty of
	* MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
	* Lesser General Public License for more details.
	*
	* You should have received a copy of the GNU Lesser General Public
	* License along with FFmpeg; if not, write to the Free Software
	* Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA
	*/

	#include <stdint.h>

	#include "libavutil/attributes.h"
	#include "libavutil/intreadwrite.h"

	#include "avcodec.h"
	#include "canopus.h"
	#include "get_bits.h"
	#include "internal.h"

	#include "hq_hqa.h"
	#include "hq_hqadsp.h"

	/* HQ/HQA slices are a set of macroblocks belonging to a frame, and
	* they usually form a pseudorandom pattern (probably because it is
	* nicer to display on partial decode).
	*
	* For HQA it just happens that each slice is on every 8th macroblock,
	* but they can be on any frame width like
	* X.......X.
	* ......X...
	* ....X.....
	* ..X.......
	* etc.
	*
	* The original decoder has special handling for edge macroblocks,
	* while lavc simply aligns coded_width and coded_height.
	*/

	static inline void put_blocks(HQContext c, AVFrame pic,
	int plane, int x, int y, int ilace,
	int16_t block0, int16_t block1)
	{
	uint8_t *p = pic->data[plane] + x;

	c->hqhqadsp.idct_put(p + y * pic->linesize[plane],
	pic->linesize[plane] << ilace, block0);
	c->hqhqadsp.idct_put(p + (y + (ilace ? 1 : 8)) * pic->linesize[plane],
	pic->linesize[plane] << ilace, block1);
	}

	static int hq_decode_block(HQContext c, GetBitContext gb, int16_t block[64],
	int qsel, int is_chroma, int is_hqa)
	{
	const int32_t *q;
	int val, pos = 1;

	memset(block, 0, 64 * sizeof(*block));

	if (!is_hqa) {
	block[0] = get_sbits(gb, 9) * 64;
	q = ff_hq_quants[qsel][is_chroma][get_bits(gb, 2)];
	} else {
	q = ff_hq_quants[qsel][is_chroma][get_bits(gb, 2)];
	block[0] = get_sbits(gb, 9) * 64;
	}

	for (;;) {
	val = get_vlc2(gb, c->hq_ac_vlc.table, 9, 2);
	if (val < 0)
	return AVERROR_INVALIDDATA;

	pos += ff_hq_ac_skips[val];
	if (pos >= 64)
	break;
	block[ff_zigzag_direct[pos]] = (int)(ff_hq_ac_syms[val] * (unsigned)q[pos]) >> 12;
	pos++;
	}

	return 0;
	}

	static int hq_decode_mb(HQContext c, AVFrame pic,
	GetBitContext *gb, int x, int y)
	{
	int qgroup, flag;
	int i, ret;

	qgroup = get_bits(gb, 4);
	flag = get_bits1(gb);

	for (i = 0; i < 8; i++) {
	ret = hq_decode_block(c, gb, c->block[i], qgroup, i >= 4, 0);
	if (ret < 0)
	return ret;
	}

	put_blocks(c, pic, 0, x, y, flag, c->block[0], c->block[2]);
	put_blocks(c, pic, 0, x + 8, y, flag, c->block[1], c->block[3]);
	put_blocks(c, pic, 2, x >> 1, y, flag, c->block[4], c->block[5]);
	put_blocks(c, pic, 1, x >> 1, y, flag, c->block[6], c->block[7]);

	return 0;
	}

	static int hq_decode_frame(HQContext ctx, AVFrame pic,
	int prof_num, size_t data_size)
	{
	const HQProfile *profile;
	GetBitContext gb;
	const uint8_t perm, src = ctx->gbc.buffer;
	uint32_t slice_off[21];
	int slice, start_off, next_off, i, ret;

	if ((unsigned)prof_num >= NUM_HQ_PROFILES) {
	profile = &ff_hq_profile[0];
	avpriv_request_sample(ctx->avctx, "HQ Profile %d", prof_num);
	} else {
	profile = &ff_hq_profile[prof_num];
	av_log(ctx->avctx, AV_LOG_VERBOSE, "HQ Profile %d\n", prof_num);
	}

	ctx->avctx->coded_width = FFALIGN(profile->width, 16);
	ctx->avctx->coded_height = FFALIGN(profile->height, 16);
	ctx->avctx->width = profile->width;
	ctx->avctx->height = profile->height;
	ctx->avctx->bits_per_raw_sample = 8;
	ctx->avctx->pix_fmt = AV_PIX_FMT_YUV422P;

	ret = ff_get_buffer(ctx->avctx, pic, 0);
	if (ret < 0)
	return ret;

	/* Offsets are stored from CUV position, so adjust them accordingly. */
	for (i = 0; i < profile->num_slices + 1; i++)
	slice_off[i] = bytestream2_get_be24(&ctx->gbc) - 4;

	next_off = 0;
	for (slice = 0; slice < profile->num_slices; slice++) {
	start_off = next_off;
	next_off = profile->tab_h * (slice + 1) / profile->num_slices;
	perm = profile->perm_tab + start_off * profile->tab_w * 2;

	if (slice_off[slice] < (profile->num_slices + 1) * 3 \|\|
	slice_off[slice] >= slice_off[slice + 1] \|\|
	slice_off[slice + 1] > data_size) {
	av_log(ctx->avctx, AV_LOG_ERROR,
	"Invalid slice size %"SIZE_SPECIFIER".\n", data_size);
	break;
	}
	init_get_bits(&gb, src + slice_off[slice],
	(slice_off[slice + 1] - slice_off[slice]) * 8);

	for (i = 0; i < (next_off - start_off) * profile->tab_w; i++) {
	ret = hq_decode_mb(ctx, pic, &gb, perm[0] * 16, perm[1] * 16);
	if (ret < 0) {
	av_log(ctx->avctx, AV_LOG_ERROR,
	"Error decoding macroblock %d at slice %d.\n", i, slice);
	return ret;
	}
	perm += 2;
	}
	}

	return 0;
	}

	static int hqa_decode_mb(HQContext c, AVFrame pic, int qgroup,
	GetBitContext *gb, int x, int y)
	{
	int flag = 0;
	int i, ret, cbp;

	cbp = get_vlc2(gb, c->hqa_cbp_vlc.table, 5, 1);

	for (i = 0; i < 12; i++)
	memset(c->block[i], 0, sizeof(*c->block));
	for (i = 0; i < 12; i++)
	c->block[i][0] = -128 * (1 << 6);

	if (cbp) {
	flag = get_bits1(gb);

	cbp \|= cbp << 4;
	if (cbp & 0x3)
	cbp \|= 0x500;
	if (cbp & 0xC)
	cbp \|= 0xA00;
	for (i = 0; i < 12; i++) {
	if (!(cbp & (1 << i)))
	continue;
	ret = hq_decode_block(c, gb, c->block[i], qgroup, i >= 8, 1);
	if (ret < 0)
	return ret;
	}
	}

	put_blocks(c, pic, 3, x, y, flag, c->block[ 0], c->block[ 2]);
	put_blocks(c, pic, 3, x + 8, y, flag, c->block[ 1], c->block[ 3]);
	put_blocks(c, pic, 0, x, y, flag, c->block[ 4], c->block[ 6]);
	put_blocks(c, pic, 0, x + 8, y, flag, c->block[ 5], c->block[ 7]);
	put_blocks(c, pic, 2, x >> 1, y, flag, c->block[ 8], c->block[ 9]);
	put_blocks(c, pic, 1, x >> 1, y, flag, c->block[10], c->block[11]);

	return 0;
	}

	static int hqa_decode_slice(HQContext ctx, AVFrame pic, GetBitContext *gb,
	int quant, int slice_no, int w, int h)
	{
	int i, j, off;
	int ret;

	for (i = 0; i < h; i += 16) {
	off = (slice_no * 16 + i * 3) & 0x70;
	for (j = off; j < w; j += 128) {
	ret = hqa_decode_mb(ctx, pic, quant, gb, j, i);
	if (ret < 0) {
	av_log(ctx->avctx, AV_LOG_ERROR,
	"Error decoding macroblock at %dx%d.\n", i, j);
	return ret;
	}
	}
	}

	return 0;
	}

	static int hqa_decode_frame(HQContext ctx, AVFrame pic, size_t data_size)
	{
	GetBitContext gb;
	const int num_slices = 8;
	uint32_t slice_off[9];
	int i, slice, ret;
	int width, height, quant;
	const uint8_t *src = ctx->gbc.buffer;

	width = bytestream2_get_be16(&ctx->gbc);
	height = bytestream2_get_be16(&ctx->gbc);

	ctx->avctx->coded_width = FFALIGN(width, 16);
	ctx->avctx->coded_height = FFALIGN(height, 16);
	ctx->avctx->width = width;
	ctx->avctx->height = height;
	ctx->avctx->bits_per_raw_sample = 8;
	ctx->avctx->pix_fmt = AV_PIX_FMT_YUVA422P;

	av_log(ctx->avctx, AV_LOG_VERBOSE, "HQA Profile\n");

	quant = bytestream2_get_byte(&ctx->gbc);
	bytestream2_skip(&ctx->gbc, 3);
	if (quant >= NUM_HQ_QUANTS) {
	av_log(ctx->avctx, AV_LOG_ERROR,
	"Invalid quantization matrix %d.\n", quant);
	return AVERROR_INVALIDDATA;
	}

	ret = ff_get_buffer(ctx->avctx, pic, 0);
	if (ret < 0)
	return ret;

	/* Offsets are stored from HQA1 position, so adjust them accordingly. */
	for (i = 0; i < num_slices + 1; i++)
	slice_off[i] = bytestream2_get_be32(&ctx->gbc) - 4;

	for (slice = 0; slice < num_slices; slice++) {
	if (slice_off[slice] < (num_slices + 1) * 3 \|\|
	slice_off[slice] >= slice_off[slice + 1] \|\|
	slice_off[slice + 1] > data_size) {
	av_log(ctx->avctx, AV_LOG_ERROR,
	"Invalid slice size %"SIZE_SPECIFIER".\n", data_size);
	break;
	}
	init_get_bits(&gb, src + slice_off[slice],
	(slice_off[slice + 1] - slice_off[slice]) * 8);

	ret = hqa_decode_slice(ctx, pic, &gb, quant, slice, width, height);
	if (ret < 0)
	return ret;
	}

	return 0;
	}

	static int hq_hqa_decode_frame(AVCodecContext avctx, void data,
	int got_frame, AVPacket avpkt)
	{
	HQContext *ctx = avctx->priv_data;
	AVFrame *pic = data;
	uint32_t info_tag;
	unsigned int data_size;
	int ret;
	unsigned tag;

	bytestream2_init(&ctx->gbc, avpkt->data, avpkt->size);
	if (bytestream2_get_bytes_left(&ctx->gbc) < 4 + 4) {
	av_log(avctx, AV_LOG_ERROR, "Frame is too small (%d).\n", avpkt->size);
	return AVERROR_INVALIDDATA;
	}

	info_tag = bytestream2_peek_le32(&ctx->gbc);
	if (info_tag == MKTAG('I', 'N', 'F', 'O')) {
	int info_size;
	bytestream2_skip(&ctx->gbc, 4);
	info_size = bytestream2_get_le32(&ctx->gbc);
	if (bytestream2_get_bytes_left(&ctx->gbc) < info_size) {
	av_log(avctx, AV_LOG_ERROR, "Invalid INFO size (%d).\n", info_size);
	return AVERROR_INVALIDDATA;
	}
	ff_canopus_parse_info_tag(avctx, ctx->gbc.buffer, info_size);

	bytestream2_skip(&ctx->gbc, info_size);
	}

	data_size = bytestream2_get_bytes_left(&ctx->gbc);
	if (data_size < 4) {
	av_log(avctx, AV_LOG_ERROR, "Frame is too small (%d).\n", data_size);
	return AVERROR_INVALIDDATA;
	}

	/* HQ defines dimensions and number of slices, and thus slice traversal
	* order. HQA has no size constraint and a fixed number of slices, so it
	* needs a separate scheme for it. */
	tag = bytestream2_get_le32(&ctx->gbc);
	if ((tag & 0x00FFFFFF) == (MKTAG('U', 'V', 'C', ' ') & 0x00FFFFFF)) {
	ret = hq_decode_frame(ctx, pic, tag >> 24, data_size);
	} else if (tag == MKTAG('H', 'Q', 'A', '1')) {
	ret = hqa_decode_frame(ctx, pic, data_size);
	} else {
	av_log(avctx, AV_LOG_ERROR, "Not a HQ/HQA frame.\n");
	return AVERROR_INVALIDDATA;
	}
	if (ret < 0) {
	av_log(avctx, AV_LOG_ERROR, "Error decoding frame.\n");
	return ret;
	}

	pic->key_frame = 1;
	pic->pict_type = AV_PICTURE_TYPE_I;

	*got_frame = 1;

	return avpkt->size;
	}

	static av_cold int hq_hqa_decode_init(AVCodecContext *avctx)
	{
	HQContext *ctx = avctx->priv_data;
	ctx->avctx = avctx;

	ff_hqdsp_init(&ctx->hqhqadsp);

	return ff_hq_init_vlcs(ctx);
	}

	static av_cold int hq_hqa_decode_close(AVCodecContext *avctx)
	{
	HQContext *ctx = avctx->priv_data;

	ff_free_vlc(&ctx->hq_ac_vlc);
	ff_free_vlc(&ctx->hqa_cbp_vlc);

	return 0;
	}

	AVCodec ff_hq_hqa_decoder = {
	.name = "hq_hqa",
	.long_name = NULL_IF_CONFIG_SMALL("Canopus HQ/HQA"),
	.type = AVMEDIA_TYPE_VIDEO,
	.id = AV_CODEC_ID_HQ_HQA,
	.priv_data_size = sizeof(HQContext),
	.init = hq_hqa_decode_init,
	.decode = hq_hqa_decode_frame,
	.close = hq_hqa_decode_close,
	.capabilities = AV_CODEC_CAP_DR1,
	.caps_internal = FF_CODEC_CAP_INIT_THREADSAFE \|
	FF_CODEC_CAP_INIT_CLEANUP,
	};