[FFmpeg-devel] [PATCH] PCX encoder
Michael Niedermayer
michaelni
Wed Mar 18 14:23:01 CET 2009
On Tue, Mar 17, 2009 at 01:14:50PM -0400, Daniel Verkamp wrote:
[...]
> +static int pcx_rle_encode( uint8_t *dst, int dst_size,
> + const uint8_t *src, int src_size)
> +{
> + int i;
> + uint8_t prev = src[0];
> + int count = 1;
> + const uint8_t *dst_start = dst;
> +
> + // check worst-case upper bound on dst_size
> + if (dst_size < 2LL * src_size)
> + return -1;
> +
> + for (i = 1; ; i++) {
> + if (i != src_size && src[i] == prev && count < 0x3F) {
> + // current byte is same as prev
> + ++count;
> + } else {
> + // output prev * count
> + if (count != 1 || prev >= 0xC0)
> + *dst++ = 0xC0 | count;
> + *dst++ = prev;
> +
> + if (i == src_size)
> + return dst - dst_start;
> +
> + // start new run
> + count = 1;
> + prev = src[i];
> + }
> + }
> +
> + return 0; // gcc warns even though this cannot be reached
does gcc still warn with the current for() ?
> +}
> +
> +static int pcx_encode_frame(AVCodecContext *avctx,
> + unsigned char *buf, int buf_size, void *data)
> +{
> + PCXContext *s = avctx->priv_data;
> + AVFrame *const pict = &s->picture;
> + const uint8_t *buf_start = buf;
> + const uint8_t *buf_end = buf + buf_size;
> +
> + int bpp, nplanes, i, j, y, p, line_bytes, written, src_line_size;
> + const uint32_t *pal = NULL;
> + const uint8_t *src;
> + uint8_t *plane;
> +
> + *pict = *(AVFrame *)data;
> + pict->pict_type = FF_I_TYPE;
> + pict->key_frame = 1;
> +
> + if (avctx->width > 65535 || avctx->height > 65535) {
> + av_log(avctx, AV_LOG_ERROR, "image dimensions do not fit in 16 bits\n");
> + return -1;
> + }
> +
> + switch (avctx->pix_fmt) {
> + case PIX_FMT_RGB24:
> + bpp = 8;
> + nplanes = 3;
> + break;
> + case PIX_FMT_RGB8:
> + case PIX_FMT_BGR8:
> + case PIX_FMT_RGB4_BYTE:
> + case PIX_FMT_BGR4_BYTE:
> + case PIX_FMT_GRAY8:
> + case PIX_FMT_PAL8:
> + bpp = 8;
> + nplanes = 1;
> + pal = (uint32_t *)pict->data[1];
> + break;
> + case PIX_FMT_MONOBLACK:
> + bpp = 1;
> + nplanes = 1;
> + pal = monoblack_pal;
> + break;
> + default:
> + av_log(avctx, AV_LOG_ERROR, "unsupported pixfmt\n");
> + return -1;
> + }
> +
> + line_bytes = (avctx->width * bpp + 7) >> 3;
> + line_bytes = (line_bytes + 1) & ~1;
> +
> + bytestream_put_byte(&buf, 10); // manufacturer
> + bytestream_put_byte(&buf, 5); // version
> + bytestream_put_byte(&buf, 1); // encoding
> + bytestream_put_byte(&buf, bpp); // bits per pixel per plane
> + bytestream_put_le16(&buf, 0); // x min
> + bytestream_put_le16(&buf, 0); // y min
> + bytestream_put_le16(&buf, avctx->width - 1); // x max
> + bytestream_put_le16(&buf, avctx->height - 1); // y max
> + bytestream_put_le16(&buf, 0); // horizontal DPI
> + bytestream_put_le16(&buf, 0); // vertical DPI
> + for (i = 0; i < 16; i++)
> + bytestream_put_be24(&buf, pal ? pal[i] : 0);// palette (<= 16 color only)
> + bytestream_put_byte(&buf, 0); // reserved
> + bytestream_put_byte(&buf, nplanes); // number of planes
> + bytestream_put_le16(&buf, line_bytes); // scanline plane size in bytes
> +
> + while (buf - buf_start < 128)
> + *buf++= 0;
> +
> + plane = av_mallocz(line_bytes);
> + src = pict->data[0];
> + src_line_size = (avctx->width * nplanes * bpp + 7) >> 3;
> +
> + for (y = 0; y < avctx->height; y++) {
> + for (p = 0; p < nplanes; p++) {
> + for (i = p, j = 0; i < src_line_size; i += nplanes, j++) {
> + plane[j] = src[i];
> + }
> + if ((written = pcx_rle_encode(buf, buf_end - buf,
> + plane, line_bytes)) < 0) {
> + av_log(avctx, AV_LOG_ERROR, "buffer too small\n");
> + av_free(plane);
> + return -1;
> + }
i think plane could be avoided by passing nplanes into pcx_rle_encode()
and i think that wouldnt make pcx_rle_encode uglier ...
[...]
--
Michael GnuPG fingerprint: 9FF2128B147EF6730BADF133611EC787040B0FAB
Avoid a single point of failure, be that a person or equipment.
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