diff --git a/libavcodec/rl2.c b/libavcodec/rl2.c index 76982f0426..7938ef1d92 100644 --- a/libavcodec/rl2.c +++ b/libavcodec/rl2.c @@ -69,13 +69,16 @@ static void rl2_rle_decode(Rl2Context *s, const uint8_t *in, int size, uint8_t *line_end; /** copy start of the background frame */ + if (s->back_frame) { for (i = 0; i <= base_y; i++) { - if (s->back_frame) memcpy(out, back_frame, s->avctx->width); out += stride; back_frame += s->avctx->width; } back_frame += base_x - s->avctx->width; + } else { + out += stride * (base_y + 1); + } line_end = out - stride_adj; out += base_x - stride; @@ -89,16 +92,32 @@ static void rl2_rle_decode(Rl2Context *s, const uint8_t *in, int size, len = *in++; if (!len) break; + val &= 0x7F; } - if (s->back_frame) + if (back_frame) { + if (!val) { + do { + size_t copy = FFMIN(line_end - out, len); + memcpy(out, back_frame, copy); + out += copy; + back_frame += copy; + len -= copy; + if (out == line_end) { + if (out == out_end) + return; + out += stride_adj; + line_end += stride; + } + } while (len > 0); + continue; + } + back_frame += len; val |= 0x80; - else - val &= ~0x80; + } while (len--) { - *out++ = (val == 0x80) ? *back_frame : val; - back_frame++; + *out++ = val; if (out == line_end) { if (out == out_end) return; @@ -164,7 +183,9 @@ static av_cold int rl2_decode_init(AVCodecContext *avctx) back_size = avctx->extradata_size - EXTRADATA1_SIZE; if (back_size > 0) { - uint8_t *back_frame = av_mallocz(avctx->width*avctx->height); + /* The 254 are padding to ensure that pointer arithmetic stays within + * the buffer. */ + uint8_t *back_frame = av_mallocz(avctx->width * avctx->height + 254); if (!back_frame) return AVERROR(ENOMEM); rl2_rle_decode(s, avctx->extradata + EXTRADATA1_SIZE, back_size,