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* Westwood Studios VQA Video Decoder
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* Copyright (C) 2003 the ffmpeg project
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* This library is free software; you can redistribute it and/or
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* modify it under the terms of the GNU Lesser General Public
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* License as published by the Free Software Foundation; either
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* version 2 of the License, or (at your option) any later version.
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* This library is distributed in the hope that it will be useful,
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* but WITHOUT ANY WARRANTY; without even the implied warranty of
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* MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
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* Lesser General Public License for more details.
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* You should have received a copy of the GNU Lesser General Public
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* License along with this library; if not, write to the Free Software
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* Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA 02111-1307 USA
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* VQA Video Decoder by Mike Melanson (melanson@pcisys.net)
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* For more information about the RPZA format, visit:
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* http://www.pcisys.net/~melanson/codecs/
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* The VQA video decoder outputs PAL8 or RGB555 colorspace data, depending
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* on the type of data in the file.
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* This decoder needs the 42-byte VQHD header from the beginning
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* of the VQA file passed through the extradata field. The VQHD header
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* bytes 0-3 chunk fourcc: 'VQHD'
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* bytes 4-7 chunk size in big-endian format, should be 0x0000002A
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* bytes 8-49 VQHD chunk data
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* Bytes 8-49 are what this decoder expects to see.
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* Briefly, VQA is a vector quantized animation format that operates in a
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* VGA palettized colorspace. It operates on pixel vectors (blocks)
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* of either 4x2 or 4x4 in size. Compressed VQA chunks can contain vector
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* codebooks, palette information, and code maps for rendering vectors onto
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* frames. Any of these components can also be compressed with a run-length
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* encoding (RLE) algorithm commonly referred to as "format80".
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* VQA takes a novel approach to rate control. Each group of n frames
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* (usually, n = 8) relies on a different vector codebook. Rather than
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* transporting an entire codebook every 8th frame, the new codebook is
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* broken up into 8 pieces and sent along with the compressed video chunks
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* for each of the 8 frames preceding the 8 frames which require the
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* codebook. A full codebook is also sent on the very first frame of a
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* file. This is an interesting technique, although it makes random file
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* seeking difficult despite the fact that the frames are all intracoded.
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* V1,2 VQA uses 12-bit codebook indices. If the 12-bit indices were
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* packed into bytes and then RLE compressed, bytewise, the results would
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* be poor. That is why the coding method divides each index into 2 parts,
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* the top 4 bits and the bottom 8 bits, then RL encodes the 4-bit pieces
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* together and the 8-bit pieces together. If most of the vectors are
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* clustered into one group of 256 vectors, most of the 4-bit index pieces
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#define PALETTE_COUNT 256
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#define VQA_HEADER_SIZE 0x2A
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#define CHUNK_PREAMBLE_SIZE 8
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/* allocate the maximum vector space, regardless of the file version:
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* (0xFF00 codebook vectors + 0x100 solid pixel vectors) * (4x4 pixels/block) */
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#define MAX_CODEBOOK_VECTORS 0xFF00
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#define SOLID_PIXEL_VECTORS 0x100
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#define MAX_VECTORS (MAX_CODEBOOK_VECTORS + SOLID_PIXEL_VECTORS)
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#define MAX_CODEBOOK_SIZE (MAX_VECTORS * 4 * 4)
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#define CBF0_TAG MKBETAG('C', 'B', 'F', '0')
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#define CBFZ_TAG MKBETAG('C', 'B', 'F', 'Z')
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#define CBP0_TAG MKBETAG('C', 'B', 'P', '0')
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#define CBPZ_TAG MKBETAG('C', 'B', 'P', 'Z')
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#define CPL0_TAG MKBETAG('C', 'P', 'L', '0')
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#define CPLZ_TAG MKBETAG('C', 'P', 'L', 'Z')
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#define VPTZ_TAG MKBETAG('V', 'P', 'T', 'Z')
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#define vqa_debug printf
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static inline void vqa_debug(const char *format, ...) { }
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typedef struct VqaContext {
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AVCodecContext *avctx;
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unsigned int palette[PALETTE_COUNT];
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int width; /* width of a frame */
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int height; /* height of a frame */
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int vector_width; /* width of individual vector */
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int vector_height; /* height of individual vector */
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int vqa_version; /* this should be either 1, 2 or 3 */
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unsigned char *codebook; /* the current codebook */
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unsigned char *next_codebook_buffer; /* accumulator for next codebook */
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int next_codebook_buffer_index;
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unsigned char *decode_buffer;
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int decode_buffer_size;
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/* number of frames to go before replacing codebook */
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int partial_countdown;
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static int vqa_decode_init(AVCodecContext *avctx)
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VqaContext *s = (VqaContext *)avctx->priv_data;
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unsigned char *vqa_header;
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int i, j, codebook_index;;
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avctx->pix_fmt = PIX_FMT_PAL8;
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avctx->has_b_frames = 0;
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dsputil_init(&s->dsp, avctx);
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/* make sure the extradata made it */
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if (s->avctx->extradata_size != VQA_HEADER_SIZE) {
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av_log(s->avctx, AV_LOG_ERROR, " VQA video: expected extradata size of %d\n", VQA_HEADER_SIZE);
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/* load up the VQA parameters from the header */
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vqa_header = (unsigned char *)s->avctx->extradata;
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s->vqa_version = vqa_header[0];
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s->width = LE_16(&vqa_header[6]);
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s->height = LE_16(&vqa_header[8]);
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s->vector_width = vqa_header[10];
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s->vector_height = vqa_header[11];
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s->partial_count = s->partial_countdown = vqa_header[13];
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/* the vector dimensions have to meet very stringent requirements */
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if ((s->vector_width != 4) ||
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((s->vector_height != 2) && (s->vector_height != 4))) {
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/* return without further initialization */
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/* allocate codebooks */
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s->codebook_size = MAX_CODEBOOK_SIZE;
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s->codebook = av_malloc(s->codebook_size);
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s->next_codebook_buffer = av_malloc(s->codebook_size);
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/* initialize the solid-color vectors */
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if (s->vector_height == 4) {
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codebook_index = 0xFF00 * 16;
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for (i = 0; i < 256; i++)
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for (j = 0; j < 16; j++)
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s->codebook[codebook_index++] = i;
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codebook_index = 0xF00 * 8;
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for (i = 0; i < 256; i++)
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for (j = 0; j < 8; j++)
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s->codebook[codebook_index++] = i;
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s->next_codebook_buffer_index = 0;
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/* allocate decode buffer */
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s->decode_buffer_size = (s->width / s->vector_width) *
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(s->height / s->vector_height) * 2;
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s->decode_buffer = av_malloc(s->decode_buffer_size);
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s->frame.data[0] = NULL;
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#define CHECK_COUNT() \
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if (dest_index + count > dest_size) { \
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av_log(NULL, AV_LOG_ERROR, " VQA video: decode_format80 problem: next op would overflow dest_index\n"); \
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av_log(NULL, AV_LOG_ERROR, " VQA video: current dest_index = %d, count = %d, dest_size = %d\n", \
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dest_index, count, dest_size); \
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static void decode_format80(unsigned char *src, int src_size,
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unsigned char *dest, int dest_size, int check_size) {
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while (src_index < src_size) {
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vqa_debug(" opcode %02X: ", src[src_index]);
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/* 0x80 means that frame is finished */
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if (src[src_index] == 0x80)
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if (dest_index >= dest_size) {
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av_log(NULL, AV_LOG_ERROR, " VQA video: decode_format80 problem: dest_index (%d) exceeded dest_size (%d)\n",
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dest_index, dest_size);
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if (src[src_index] == 0xFF) {
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count = LE_16(&src[src_index]);
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src_pos = LE_16(&src[src_index]);
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vqa_debug("(1) copy %X bytes from absolute pos %X\n", count, src_pos);
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for (i = 0; i < count; i++)
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dest[dest_index + i] = dest[src_pos + i];
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} else if (src[src_index] == 0xFE) {
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count = LE_16(&src[src_index]);
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color = src[src_index++];
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vqa_debug("(2) set %X bytes to %02X\n", count, color);
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memset(&dest[dest_index], color, count);
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} else if ((src[src_index] & 0xC0) == 0xC0) {
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count = (src[src_index++] & 0x3F) + 3;
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src_pos = LE_16(&src[src_index]);
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vqa_debug("(3) copy %X bytes from absolute pos %X\n", count, src_pos);
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for (i = 0; i < count; i++)
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dest[dest_index + i] = dest[src_pos + i];
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} else if (src[src_index] > 0x80) {
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count = src[src_index++] & 0x3F;
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vqa_debug("(4) copy %X bytes from source to dest\n", count);
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memcpy(&dest[dest_index], &src[src_index], count);
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count = ((src[src_index] & 0x70) >> 4) + 3;
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src_pos = BE_16(&src[src_index]) & 0x0FFF;
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vqa_debug("(5) copy %X bytes from relpos %X\n", count, src_pos);
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for (i = 0; i < count; i++)
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dest[dest_index + i] = dest[dest_index - src_pos + i];
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/* validate that the entire destination buffer was filled; this is
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* important for decoding frame maps since each vector needs to have a
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* codebook entry; it is not important for compressed codebooks because
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* not every entry needs to be filled */
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if (dest_index < dest_size)
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av_log(NULL, AV_LOG_ERROR, " VQA video: decode_format80 problem: decode finished with dest_index (%d) < dest_size (%d)\n",
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dest_index, dest_size);
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static void vqa_decode_chunk(VqaContext *s)
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unsigned int chunk_type;
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unsigned int chunk_size;
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unsigned int index = 0;
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unsigned char r, g, b;
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int vector_index = 0;
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int hibytes = s->decode_buffer_size / 2;
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/* first, traverse through the frame and find the subchunks */
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while (index < s->size) {
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chunk_type = BE_32(&s->buf[index]);
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chunk_size = BE_32(&s->buf[index + 4]);
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switch (chunk_type) {
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av_log(s->avctx, AV_LOG_ERROR, " VQA video: Found unknown chunk type: %c%c%c%c (%08X)\n",
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(chunk_type >> 24) & 0xFF,
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(chunk_type >> 16) & 0xFF,
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(chunk_type >> 8) & 0xFF,
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(chunk_type >> 0) & 0xFF,
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byte_skip = chunk_size & 0x01;
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index += (CHUNK_PREAMBLE_SIZE + chunk_size + byte_skip);
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/* next, deal with the palette */
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if ((cpl0_chunk != -1) && (cplz_chunk != -1)) {
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/* a chunk should not have both chunk types */
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av_log(s->avctx, AV_LOG_ERROR, " VQA video: problem: found both CPL0 and CPLZ chunks\n");
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/* decompress the palette chunk */
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if (cplz_chunk != -1) {
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/* yet to be handled */
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/* convert the RGB palette into the machine's endian format */
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if (cpl0_chunk != -1) {
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chunk_size = BE_32(&s->buf[cpl0_chunk + 4]);
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/* sanity check the palette size */
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if (chunk_size / 3 > 256) {
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av_log(s->avctx, AV_LOG_ERROR, " VQA video: problem: found a palette chunk with %d colors\n",
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cpl0_chunk += CHUNK_PREAMBLE_SIZE;
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for (i = 0; i < chunk_size / 3; i++) {
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/* scale by 4 to transform 6-bit palette -> 8-bit */
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r = s->buf[cpl0_chunk++] * 4;
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g = s->buf[cpl0_chunk++] * 4;
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b = s->buf[cpl0_chunk++] * 4;
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s->palette[i] = (r << 16) | (g << 8) | (b);
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/* next, look for a full codebook */
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if ((cbf0_chunk != -1) && (cbfz_chunk != -1)) {
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/* a chunk should not have both chunk types */
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av_log(s->avctx, AV_LOG_ERROR, " VQA video: problem: found both CBF0 and CBFZ chunks\n");
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/* decompress the full codebook chunk */
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if (cbfz_chunk != -1) {
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chunk_size = BE_32(&s->buf[cbfz_chunk + 4]);
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cbfz_chunk += CHUNK_PREAMBLE_SIZE;
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decode_format80(&s->buf[cbfz_chunk], chunk_size,
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s->codebook, s->codebook_size, 0);
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/* copy a full codebook */
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if (cbf0_chunk != -1) {
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chunk_size = BE_32(&s->buf[cbf0_chunk + 4]);
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/* sanity check the full codebook size */
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if (chunk_size > MAX_CODEBOOK_SIZE) {
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av_log(s->avctx, AV_LOG_ERROR, " VQA video: problem: CBF0 chunk too large (0x%X bytes)\n",
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cbf0_chunk += CHUNK_PREAMBLE_SIZE;
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memcpy(s->codebook, &s->buf[cbf0_chunk], chunk_size);
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/* decode the frame */
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if (vptz_chunk == -1) {
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/* something is wrong if there is no VPTZ chunk */
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av_log(s->avctx, AV_LOG_ERROR, " VQA video: problem: no VPTZ chunk found\n");
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chunk_size = BE_32(&s->buf[vptz_chunk + 4]);
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vptz_chunk += CHUNK_PREAMBLE_SIZE;
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decode_format80(&s->buf[vptz_chunk], chunk_size,
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s->decode_buffer, s->decode_buffer_size, 1);
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/* render the final PAL8 frame */
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if (s->vector_height == 4)
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for (y = 0; y < s->frame.linesize[0] * s->height;
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y += s->frame.linesize[0] * s->vector_height) {
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for (x = y; x < y + s->width; x += 4, lobytes++, hibytes++) {
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/* get the vector index, the method for which varies according to
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* VQA file version */
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switch (s->vqa_version) {
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/* still need sample media for this case (only one game, "Legend of
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* Kyrandia III : Malcolm's Revenge", is known to use this version) */
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lobyte = s->decode_buffer[lobytes];
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hibyte = s->decode_buffer[hibytes];
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vector_index = (hibyte << 8) | lobyte;
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vector_index <<= index_shift;
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lines = s->vector_height;
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/* not implemented yet */
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s->frame.data[0][pixel_ptr + 0] = s->codebook[vector_index++];
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s->frame.data[0][pixel_ptr + 1] = s->codebook[vector_index++];
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s->frame.data[0][pixel_ptr + 2] = s->codebook[vector_index++];
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s->frame.data[0][pixel_ptr + 3] = s->codebook[vector_index++];
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pixel_ptr += s->frame.linesize[0];
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/* handle partial codebook */
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if ((cbp0_chunk != -1) && (cbpz_chunk != -1)) {
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/* a chunk should not have both chunk types */
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av_log(s->avctx, AV_LOG_ERROR, " VQA video: problem: found both CBP0 and CBPZ chunks\n");
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if (cbp0_chunk != -1) {
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chunk_size = BE_32(&s->buf[cbp0_chunk + 4]);
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cbp0_chunk += CHUNK_PREAMBLE_SIZE;
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/* accumulate partial codebook */
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memcpy(&s->next_codebook_buffer[s->next_codebook_buffer_index],
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&s->buf[cbp0_chunk], chunk_size);
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s->next_codebook_buffer_index += chunk_size;
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s->partial_countdown--;
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if (s->partial_countdown == 0) {
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/* time to replace codebook */
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memcpy(s->codebook, s->next_codebook_buffer,
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s->next_codebook_buffer_index);
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/* reset accounting */
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s->next_codebook_buffer_index = 0;
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s->partial_countdown = s->partial_count;
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if (cbpz_chunk != -1) {
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chunk_size = BE_32(&s->buf[cbpz_chunk + 4]);
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cbpz_chunk += CHUNK_PREAMBLE_SIZE;
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/* accumulate partial codebook */
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memcpy(&s->next_codebook_buffer[s->next_codebook_buffer_index],
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&s->buf[cbpz_chunk], chunk_size);
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s->next_codebook_buffer_index += chunk_size;
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s->partial_countdown--;
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if (s->partial_countdown == 0) {
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/* decompress codebook */
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decode_format80(s->next_codebook_buffer,
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s->next_codebook_buffer_index,
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s->codebook, s->codebook_size, 0);
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/* reset accounting */
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s->next_codebook_buffer_index = 0;
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s->partial_countdown = s->partial_count;
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static int vqa_decode_frame(AVCodecContext *avctx,
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void *data, int *data_size,
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uint8_t *buf, int buf_size)
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VqaContext *s = (VqaContext *)avctx->priv_data;
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if (s->frame.data[0])
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avctx->release_buffer(avctx, &s->frame);
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if (avctx->get_buffer(avctx, &s->frame)) {
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av_log(s->avctx, AV_LOG_ERROR, " VQA Video: get_buffer() failed\n");
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/* make the palette available on the way out */
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memcpy(s->frame.data[1], s->palette, PALETTE_COUNT * 4);
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s->frame.palette_has_changed = 1;
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*data_size = sizeof(AVFrame);
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*(AVFrame*)data = s->frame;
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/* report that the buffer was completely consumed */
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static int vqa_decode_end(AVCodecContext *avctx)
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VqaContext *s = (VqaContext *)avctx->priv_data;
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av_free(s->codebook);
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av_free(s->next_codebook_buffer);
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av_free(s->decode_buffer);
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if (s->frame.data[0])
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avctx->release_buffer(avctx, &s->frame);
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AVCodec vqa_decoder = {
added
removed
extras/ffmpeg/libavcodec/vqavideo.c
