truemotion1.c

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        av_log(s->avctx, AV_LOG_INFO, "tables: %d / %d c:%d %dx%d t:%d %s%s%s%s\n",
            s->last_deltaset, s->last_vectable, s->compression, s->block_width,
            s->block_height, s->block_type,
            s->flags & FLAG_KEYFRAME ? " KEY" : "",
            s->flags & FLAG_INTERFRAME ? " INTER" : "",
            s->flags & FLAG_SPRITE ? " SPRITE" : "",
            s->flags & FLAG_INTERPOLATED ? " INTERPOL" : "");

    return header.header_size;
}

static int truemotion1_decode_init(AVCodecContext *avctx)
{
    TrueMotion1Context *s = avctx->priv_data;

    s->avctx = avctx;

    // FIXME: it may change ?
//    if (avctx->bits_per_sample == 24)
//        avctx->pix_fmt = PIX_FMT_RGB24;
//    else
//        avctx->pix_fmt = PIX_FMT_RGB555;

    s->frame.data[0] = NULL;

    /* there is a vertical predictor for each pixel in a line; each vertical
     * predictor is 0 to start with */
    s->vert_pred =
        (unsigned int *)av_malloc(s->avctx->width * sizeof(unsigned int));

    return 0;
}

/*
Block decoding order:

dxi: Y-Y
dxic: Y-C-Y
dxic2: Y-C-Y-C

hres,vres,i,i%vres (0 < i < 4)
2x2 0: 0 dxic2
2x2 1: 1 dxi
2x2 2: 0 dxic2
2x2 3: 1 dxi
2x4 0: 0 dxic2
2x4 1: 1 dxi
2x4 2: 2 dxi
2x4 3: 3 dxi
4x2 0: 0 dxic
4x2 1: 1 dxi
4x2 2: 0 dxic
4x2 3: 1 dxi
4x4 0: 0 dxic
4x4 1: 1 dxi
4x4 2: 2 dxi
4x4 3: 3 dxi
*/

#define GET_NEXT_INDEX() \
{\
    if (index_stream_index >= s->index_stream_size) { \
        av_log(s->avctx, AV_LOG_INFO, " help! truemotion1 decoder went out of bounds\n"); \
        return; \
    } \
    index = s->index_stream[index_stream_index++] * 4; \
}

#define APPLY_C_PREDICTOR() \
    predictor_pair = s->c_predictor_table[index]; \
    horiz_pred += (predictor_pair >> 1); \
    if (predictor_pair & 1) { \
        GET_NEXT_INDEX() \
        if (!index) { \
            GET_NEXT_INDEX() \
            predictor_pair = s->c_predictor_table[index]; \
            horiz_pred += ((predictor_pair >> 1) * 5); \
            if (predictor_pair & 1) \
                GET_NEXT_INDEX() \
            else \
                index++; \
        } \
    } else \
        index++;

#define APPLY_C_PREDICTOR_24() \
    predictor_pair = s->c_predictor_table[index]; \
    horiz_pred += (predictor_pair >> 1); \
    if (predictor_pair & 1) { \
        GET_NEXT_INDEX() \
        if (!index) { \
            GET_NEXT_INDEX() \
            predictor_pair = s->fat_c_predictor_table[index]; \
            horiz_pred += (predictor_pair >> 1); \
            if (predictor_pair & 1) \
                GET_NEXT_INDEX() \
            else \
                index++; \
        } \
    } else \
        index++;


#define APPLY_Y_PREDICTOR() \
    predictor_pair = s->y_predictor_table[index]; \
    horiz_pred += (predictor_pair >> 1); \
    if (predictor_pair & 1) { \
        GET_NEXT_INDEX() \
        if (!index) { \
            GET_NEXT_INDEX() \
            predictor_pair = s->y_predictor_table[index]; \
            horiz_pred += ((predictor_pair >> 1) * 5); \
            if (predictor_pair & 1) \
                GET_NEXT_INDEX() \
            else \
                index++; \
        } \
    } else \
        index++;

#define APPLY_Y_PREDICTOR_24() \
    predictor_pair = s->y_predictor_table[index]; \
    horiz_pred += (predictor_pair >> 1); \
    if (predictor_pair & 1) { \
        GET_NEXT_INDEX() \
        if (!index) { \
            GET_NEXT_INDEX() \
            predictor_pair = s->fat_y_predictor_table[index]; \
            horiz_pred += (predictor_pair >> 1); \
            if (predictor_pair & 1) \
                GET_NEXT_INDEX() \
            else \
                index++; \
        } \
    } else \
        index++;

#define OUTPUT_PIXEL_PAIR() \
    *current_pixel_pair = *vert_pred + horiz_pred; \
    *vert_pred++ = *current_pixel_pair++;

static void truemotion1_decode_16bit(TrueMotion1Context *s)
{
    int y;
    int pixels_left;  /* remaining pixels on this line */
    unsigned int predictor_pair;
    unsigned int horiz_pred;
    unsigned int *vert_pred;
    unsigned int *current_pixel_pair;
    unsigned char *current_line = s->frame.data[0];
    int keyframe = s->flags & FLAG_KEYFRAME;

    /* these variables are for managing the stream of macroblock change bits */
    unsigned char *mb_change_bits = s->mb_change_bits;
    unsigned char mb_change_byte;
    unsigned char mb_change_byte_mask;
    int mb_change_index;

    /* these variables are for managing the main index stream */
    int index_stream_index = 0;  /* yes, the index into the index stream */
    int index;

    /* clean out the line buffer */
    memset(s->vert_pred, 0, s->avctx->width * sizeof(unsigned int));

    GET_NEXT_INDEX();

    for (y = 0; y < s->avctx->height; y++) {

        /* re-init variables for the next line iteration */
        horiz_pred = 0;
        current_pixel_pair = (unsigned int *)current_line;
        vert_pred = s->vert_pred;
        mb_change_index = 0;
        mb_change_byte = mb_change_bits[mb_change_index++];
        mb_change_byte_mask = 0x01;
        pixels_left = s->avctx->width;

        while (pixels_left > 0) {

            if (keyframe || ((mb_change_byte & mb_change_byte_mask) == 0)) {

                switch (y & 3) {
                case 0:
                    /* if macroblock width is 2, apply C-Y-C-Y; else
                     * apply C-Y-Y */
                    if (s->block_width == 2) {
                        APPLY_C_PREDICTOR();
                        APPLY_Y_PREDICTOR();
                        OUTPUT_PIXEL_PAIR();
                        APPLY_C_PREDICTOR();
                        APPLY_Y_PREDICTOR();
                        OUTPUT_PIXEL_PAIR();
                    } else {
                        APPLY_C_PREDICTOR();
                        APPLY_Y_PREDICTOR();
                        OUTPUT_PIXEL_PAIR();
                        APPLY_Y_PREDICTOR();
                        OUTPUT_PIXEL_PAIR();
                    }
                    break;

                case 1:
                case 3:
                    /* always apply 2 Y predictors on these iterations */
                    APPLY_Y_PREDICTOR();
                    OUTPUT_PIXEL_PAIR();
                    APPLY_Y_PREDICTOR();
                    OUTPUT_PIXEL_PAIR();
                    break;

                case 2:
                    /* this iteration might be C-Y-C-Y, Y-Y, or C-Y-Y
                     * depending on the macroblock type */
                    if (s->block_type == BLOCK_2x2) {
                        APPLY_C_PREDICTOR();
                        APPLY_Y_PREDICTOR();
                        OUTPUT_PIXEL_PAIR();
                        APPLY_C_PREDICTOR();
                        APPLY_Y_PREDICTOR();
                        OUTPUT_PIXEL_PAIR();
                    } else if (s->block_type == BLOCK_4x2) {
                        APPLY_C_PREDICTOR();
                        APPLY_Y_PREDICTOR();
                        OUTPUT_PIXEL_PAIR();
                        APPLY_Y_PREDICTOR();
                        OUTPUT_PIXEL_PAIR();
                    } else {
                        APPLY_Y_PREDICTOR();
                        OUTPUT_PIXEL_PAIR();
                        APPLY_Y_PREDICTOR();
                        OUTPUT_PIXEL_PAIR();
                    }
                    break;
                }

            } else {

                /* skip (copy) four pixels, but reassign the horizontal
                 * predictor */
                *vert_pred++ = *current_pixel_pair++;
                horiz_pred = *current_pixel_pair - *vert_pred;
                *vert_pred++ = *current_pixel_pair++;

            }

            if (!keyframe) {
                mb_change_byte_mask <<= 1;

                /* next byte */
                if (!mb_change_byte_mask) {
                    mb_change_byte = mb_change_bits[mb_change_index++];
                    mb_change_byte_mask = 0x01;
                }
            }

            pixels_left -= 4;
        }

        /* next change row */
        if (((y + 1) & 3) == 0)
            mb_change_bits += s->mb_change_bits_row_size;

        current_line += s->frame.linesize[0];
    }
}

static void truemotion1_decode_24bit(TrueMotion1Context *s)
{
    int y;
    int pixels_left;  /* remaining pixels on this line */
    unsigned int predictor_pair;
    unsigned int horiz_pred;
    unsigned int *vert_pred;
    unsigned int *current_pixel_pair;
    unsigned char *current_line = s->frame.data[0];
    int keyframe = s->flags & FLAG_KEYFRAME;

    /* these variables are for managing the stream of macroblock change bits */
    unsigned char *mb_change_bits = s->mb_change_bits;
    unsigned char mb_change_byte;
    unsigned char mb_change_byte_mask;
    int mb_change_index;

    /* these variables are for managing the main index stream */
    int index_stream_index = 0;  /* yes, the index into the index stream */
    int index;

    /* clean out the line buffer */
    memset(s->vert_pred, 0, s->avctx->width * sizeof(unsigned int));

    GET_NEXT_INDEX();

    for (y = 0; y < s->avctx->height; y++) {

        /* re-init variables for the next line iteration */
        horiz_pred = 0;
        current_pixel_pair = (unsigned int *)current_line;
        vert_pred = s->vert_pred;
        mb_change_index = 0;
        mb_change_byte = mb_change_bits[mb_change_index++];
        mb_change_byte_mask = 0x01;
        pixels_left = s->avctx->width;

        while (pixels_left > 0) {

            if (keyframe || ((mb_change_byte & mb_change_byte_mask) == 0)) {

                switch (y & 3) {
                case 0:
                    /* if macroblock width is 2, apply C-Y-C-Y; else
                     * apply C-Y-Y */
                    if (s->block_width == 2) {
                        APPLY_C_PREDICTOR_24();
                        APPLY_Y_PREDICTOR_24();
                        OUTPUT_PIXEL_PAIR();
                        APPLY_C_PREDICTOR_24();
                        APPLY_Y_PREDICTOR_24();
                        OUTPUT_PIXEL_PAIR();
                    } else {
                        APPLY_C_PREDICTOR_24();
                        APPLY_Y_PREDICTOR_24();
                        OUTPUT_PIXEL_PAIR();
                        APPLY_Y_PREDICTOR_24();
                        OUTPUT_PIXEL_PAIR();
                    }
                    break;

                case 1:
                case 3:
                    /* always apply 2 Y predictors on these iterations */
                    APPLY_Y_PREDICTOR_24();
                    OUTPUT_PIXEL_PAIR();
                    APPLY_Y_PREDICTOR_24();
                    OUTPUT_PIXEL_PAIR();
                    break;

                case 2:
                    /* this iteration might be C-Y-C-Y, Y-Y, or C-Y-Y
                     * depending on the macroblock type */
                    if (s->block_type == BLOCK_2x2) {
                        APPLY_C_PREDICTOR_24();
                        APPLY_Y_PREDICTOR_24();
                        OUTPUT_PIXEL_PAIR();
                        APPLY_C_PREDICTOR_24();
                        APPLY_Y_PREDICTOR_24();
                        OUTPUT_PIXEL_PAIR();
                    } else if (s->block_type == BLOCK_4x2) {
                        APPLY_C_PREDICTOR_24();
                        APPLY_Y_PREDICTOR_24();
                        OUTPUT_PIXEL_PAIR();
                        APPLY_Y_PREDICTOR_24();
                        OUTPUT_PIXEL_PAIR();
                    } else {
                        APPLY_Y_PREDICTOR_24();
                        OUTPUT_PIXEL_PAIR();
                        APPLY_Y_PREDICTOR_24();
                        OUTPUT_PIXEL_PAIR();
                    }
                    break;
                }

            } else {

                /* skip (copy) four pixels, but reassign the horizontal
                 * predictor */
                *vert_pred++ = *current_pixel_pair++;
                horiz_pred = *current_pixel_pair - *vert_pred;
                *vert_pred++ = *current_pixel_pair++;

            }

            if (!keyframe) {
                mb_change_byte_mask <<= 1;

                /* next byte */
                if (!mb_change_byte_mask) {
                    mb_change_byte = mb_change_bits[mb_change_index++];
                    mb_change_byte_mask = 0x01;
                }
            }

            pixels_left -= 4;
        }

        /* next change row */
        if (((y + 1) & 3) == 0)
            mb_change_bits += s->mb_change_bits_row_size;

        current_line += s->frame.linesize[0];
    }
}


static int truemotion1_decode_frame(AVCodecContext *avctx,
                                    void *data, int *data_size,
                                    uint8_t *buf, int buf_size)
{
    TrueMotion1Context *s = avctx->priv_data;

    s->buf = buf;
    s->size = buf_size;

    if (truemotion1_decode_header(s) == -1)
        return -1;

    s->frame.reference = 1;
    s->frame.buffer_hints = FF_BUFFER_HINTS_VALID |
        FF_BUFFER_HINTS_PRESERVE | FF_BUFFER_HINTS_REUSABLE;
    if (avctx->reget_buffer(avctx, &s->frame) < 0) {
        av_log(s->avctx, AV_LOG_ERROR, "get_buffer() failed\n");
        return -1;
    }

    if (compression_types[s->compression].algorithm == ALGO_RGB24H) {
        truemotion1_decode_24bit(s);
    } else if (compression_types[s->compression].algorithm != ALGO_NOP) {
        truemotion1_decode_16bit(s);
    }

    *data_size = sizeof(AVFrame);
    *(AVFrame*)data = s->frame;

    /* report that the buffer was completely consumed */
    return buf_size;
}

static int truemotion1_decode_end(AVCodecContext *avctx)
{
    TrueMotion1Context *s = avctx->priv_data;

    if (s->frame.data[0])
        avctx->release_buffer(avctx, &s->frame);

    av_free(s->vert_pred);

    return 0;
}

AVCodec truemotion1_decoder = {
    "truemotion1",
    CODEC_TYPE_VIDEO,
    CODEC_ID_TRUEMOTION1,
    sizeof(TrueMotion1Context),
    truemotion1_decode_init,
    NULL,
    truemotion1_decode_end,
    truemotion1_decode_frame,
    CODEC_CAP_DR1,
};