ffmpeg | branch: master | Donny Yang <work@kota.moe> | Fri Aug 28 13:53:07 2015 +0000| [51d4bca5a40b8087c43421873e1c2262b6a74a76] | committer: Paul B Mahol avcodec/pngdec: fully support the tRNS chunk Signed-off-by: Donny Yang <work@kota.moe>

http://git.videolan.org/gitweb.cgi/ffmpeg.git/?a=commit;h=51d4bca5a40b8087c4...

libavcodec/pngdec.c | 98 ++++++++++++++++++++++++++++++++++++++++++++++----- 1 file changed, 89 insertions(+), 9 deletions(-) diff --git a/libavcodec/pngdec.c b/libavcodec/pngdec.c index 6e7eae0..ee11f12 100644 --- a/libavcodec/pngdec.c +++ b/libavcodec/pngdec.c @@ -21,6 +21,7 @@ //#define DEBUG +#include "libavutil/avassert.h" #include "libavutil/bprint.h" #include "libavutil/imgutils.h" #include "avcodec.h" @@ -59,6 +60,7 @@ typedef struct PNGDecContext { int bits_per_pixel; int bpp; int has_trns; + uint8_t transparent_color_be[6]; uint8_t *image_buf; int image_linesize; @@ -590,6 +592,7 @@ static int decode_idat_chunk(AVCodecContext *avctx, PNGDecContext *s, uint32_t length, AVFrame *p) { int ret; + size_t byte_depth = s->bit_depth > 8 ? 2 : 1; if (!(s->state & PNG_IHDR)) { av_log(avctx, AV_LOG_ERROR, "IDAT without IHDR\n"); @@ -641,6 +644,31 @@ static int decode_idat_chunk(AVCodecContext *avctx, PNGDecContext *s, return AVERROR_INVALIDDATA; } + if (s->has_trns && s->color_type != PNG_COLOR_TYPE_PALETTE) { + switch (avctx->pix_fmt) { + case AV_PIX_FMT_RGB24: + avctx->pix_fmt = AV_PIX_FMT_RGBA; + break; + + case AV_PIX_FMT_RGB48BE: + avctx->pix_fmt = AV_PIX_FMT_RGBA64BE; + break; + + case AV_PIX_FMT_GRAY8: + avctx->pix_fmt = AV_PIX_FMT_YA8; + break; + + case AV_PIX_FMT_GRAY16BE: + avctx->pix_fmt = AV_PIX_FMT_YA16BE; + break; + + default: + av_assert0(0); + } + + s->bpp += byte_depth; + } + if ((ret = ff_thread_get_buffer(avctx, &s->picture, AV_GET_BUFFER_FLAG_REF)) < 0) return ret; if (avctx->codec_id == AV_CODEC_ID_APNG && s->last_dispose_op != APNG_DISPOSE_OP_PREVIOUS) { @@ -691,9 +719,21 @@ static int decode_idat_chunk(AVCodecContext *avctx, PNGDecContext *s, s->zstream.avail_out = s->crow_size; s->zstream.next_out = s->crow_buf; } + s->state |= PNG_IDAT; - if ((ret = png_decode_idat(s, length)) < 0) + + /* set image to non-transparent bpp while decompressing */ + if (s->has_trns && s->color_type != PNG_COLOR_TYPE_PALETTE) + s->bpp -= byte_depth; + + ret = png_decode_idat(s, length); + + if (s->has_trns && s->color_type != PNG_COLOR_TYPE_PALETTE) + s->bpp += byte_depth; + + if (ret < 0) return ret; + bytestream2_skip(&s->gb, 4); /* crc */ return 0; @@ -727,17 +767,33 @@ static int decode_trns_chunk(AVCodecContext *avctx, PNGDecContext *s, { int v, i; - /* read the transparency. XXX: Only palette mode supported */ - if (s->color_type != PNG_COLOR_TYPE_PALETTE || - length > 256 || - !(s->state & PNG_PLTE)) + if (s->color_type == PNG_COLOR_TYPE_PALETTE) { + if (length > 256 || !(s->state & PNG_PLTE)) + return AVERROR_INVALIDDATA; + + for (i = 0; i < length; i++) { + v = bytestream2_get_byte(&s->gb); + s->palette[i] = (s->palette[i] & 0x00ffffff) | (v << 24); + } + } else if (s->color_type == PNG_COLOR_TYPE_GRAY || s->color_type == PNG_COLOR_TYPE_RGB) { + if ((s->color_type == PNG_COLOR_TYPE_GRAY && length != 2) || + (s->color_type == PNG_COLOR_TYPE_RGB && length != 6)) + return AVERROR_INVALIDDATA; + + for (i = 0; i < length / 2; i++) { + /* only use the least significant bits */ + v = bytestream2_get_be16(&s->gb) & ((1 << s->bit_depth) - 1); + + if (s->bit_depth > 8) + AV_WB16(&s->transparent_color_be[2 * i], v); + else + s->transparent_color_be[i] = v; + } + } else { return AVERROR_INVALIDDATA; - for (i = 0; i < length; i++) { - v = bytestream2_get_byte(&s->gb); - s->palette[i] = (s->palette[i] & 0x00ffffff) | (v << 24); } - bytestream2_skip(&s->gb, 4); /* crc */ + bytestream2_skip(&s->gb, 4); /* crc */ s->has_trns = 1; return 0; @@ -1122,6 +1178,29 @@ exit_loop: if (s->bits_per_pixel <= 4) handle_small_bpp(s, p); + /* apply transparency if needed */ + if (s->has_trns && s->color_type != PNG_COLOR_TYPE_PALETTE) { + size_t byte_depth = s->bit_depth > 8 ? 2 : 1; + size_t raw_bpp = s->bpp - byte_depth; + unsigned x, y; + + for (y = 0; y < s->height; ++y) { + uint8_t *row = &s->image_buf[s->image_linesize * y]; + + /* since we're updating in-place, we have to go from right to left */ + for (x = s->width; x > 0; --x) { + uint8_t *pixel = &row[s->bpp * (x - 1)]; + memmove(pixel, &row[raw_bpp * (x - 1)], raw_bpp); + + if (!memcmp(pixel, s->transparent_color_be, raw_bpp)) { + memset(&pixel[raw_bpp], 0, byte_depth); + } else { + memset(&pixel[raw_bpp], 0xff, byte_depth); + } + } + } + } + /* handle p-frames only if a predecessor frame is available */ if (s->last_picture.f->data[0]) { if ( !(avpkt->flags & AV_PKT_FLAG_KEY) && avctx->codec_tag != AV_RL32("MPNG") @@ -1285,6 +1364,7 @@ static int update_thread_context(AVCodecContext *dst, const AVCodecContext *src) pdst->x_offset = psrc->x_offset; pdst->y_offset = psrc->y_offset; pdst->has_trns = psrc->has_trns; + memcpy(pdst->transparent_color_be, psrc->transparent_color_be, sizeof(pdst->transparent_color_be)); pdst->dispose_op = psrc->dispose_op;