Module: libav Branch: master Commit: 74b1bf632f125a795e66e5fd0a060b9c7c55b7a3
Author: Luca Barbato <[email protected]> Committer: Diego Biurrun <[email protected]> Date: Tue Apr 19 06:35:53 2016 +0200 mp3: Make the extrasize explicit Initialize the bit buffer with the correct size (amount of bits that will be read) instead of relying on the bitstream reader overreading the correct values. Signed-off-by: Luca Barbato <[email protected]> Signed-off-by: Diego Biurrun <[email protected]> --- libavcodec/mpegaudiodec_template.c | 29 +++++++++++++++-------------- 1 file changed, 15 insertions(+), 14 deletions(-) diff --git a/libavcodec/mpegaudiodec_template.c b/libavcodec/mpegaudiodec_template.c index 2518387..9bfba6f 100644 --- a/libavcodec/mpegaudiodec_template.c +++ b/libavcodec/mpegaudiodec_template.c @@ -70,6 +70,7 @@ typedef struct MPADecodeContext { MPA_DECODE_HEADER uint8_t last_buf[LAST_BUF_SIZE]; int last_buf_size; + int extrasize; /* next header (used in free format parsing) */ uint32_t free_format_next_header; GetBitContext gb; @@ -798,9 +799,10 @@ static void exponents_from_scale_factors(MPADecodeContext *s, GranuleDef *g, static void switch_buffer(MPADecodeContext *s, int *pos, int *end_pos, int *end_pos2) { - if (s->in_gb.buffer && *pos >= s->gb.size_in_bits) { + if (s->in_gb.buffer && *pos >= s->gb.size_in_bits - s->extrasize * 8) { s->gb = s->in_gb; s->in_gb.buffer = NULL; + s->extrasize = 0; assert((get_bits_count(&s->gb) & 7) == 0); skip_bits_long(&s->gb, *pos - *end_pos); *end_pos2 = @@ -832,7 +834,7 @@ static int huffman_decode(MPADecodeContext *s, GranuleDef *g, int i; int last_pos, bits_left; VLC *vlc; - int end_pos = FFMIN(end_pos2, s->gb.size_in_bits); + int end_pos = FFMIN(end_pos2, s->gb.size_in_bits - s->extrasize * 8); /* low frequencies (called big values) */ s_index = 0; @@ -1354,19 +1356,16 @@ static int mp_decode_layer3(MPADecodeContext *s) if (!s->adu_mode) { int skip; const uint8_t *ptr = s->gb.buffer + (get_bits_count(&s->gb)>>3); - int extrasize = av_clip(get_bits_left(&s->gb) >> 3, 0, - FFMAX(0, LAST_BUF_SIZE - s->last_buf_size)); + s->extrasize = av_clip((get_bits_left(&s->gb) >> 3) - s->extrasize, 0, + FFMAX(0, LAST_BUF_SIZE - s->last_buf_size)); assert((get_bits_count(&s->gb) & 7) == 0); /* now we get bits from the main_data_begin offset */ ff_dlog(s->avctx, "seekback:%d, lastbuf:%d\n", main_data_begin, s->last_buf_size); - memcpy(s->last_buf + s->last_buf_size, ptr, extrasize); + memcpy(s->last_buf + s->last_buf_size, ptr, s->extrasize); s->in_gb = s->gb; - init_get_bits(&s->gb, s->last_buf, s->last_buf_size*8); -#if !UNCHECKED_BITSTREAM_READER - s->gb.size_in_bits_plus8 += extrasize * 8; -#endif + init_get_bits(&s->gb, s->last_buf, (s->last_buf_size + s->extrasize) * 8); s->last_buf_size <<= 3; for (gr = 0; gr < nb_granules && (s->last_buf_size >> 3) < main_data_begin; gr++) { for (ch = 0; ch < s->nb_channels; ch++) { @@ -1377,15 +1376,17 @@ static int mp_decode_layer3(MPADecodeContext *s) } } skip = s->last_buf_size - 8 * main_data_begin; - if (skip >= s->gb.size_in_bits && s->in_gb.buffer) { - skip_bits_long(&s->in_gb, skip - s->gb.size_in_bits); + if (skip >= s->gb.size_in_bits - s->extrasize * 8 && s->in_gb.buffer) { + skip_bits_long(&s->in_gb, skip - s->gb.size_in_bits + s->extrasize * 8); s->gb = s->in_gb; s->in_gb.buffer = NULL; + s->extrasize = 0; } else { skip_bits_long(&s->gb, skip); } } else { gr = 0; + s->extrasize = 0; } for (; gr < nb_granules; gr++) { @@ -1553,7 +1554,7 @@ static int mp_decode_frame(MPADecodeContext *s, OUT_INT **samples, s->last_buf_size=0; if (s->in_gb.buffer) { align_get_bits(&s->gb); - i = get_bits_left(&s->gb)>>3; + i = (get_bits_left(&s->gb) >> 3) - s->extrasize; if (i >= 0 && i <= BACKSTEP_SIZE) { memmove(s->last_buf, s->gb.buffer + (get_bits_count(&s->gb)>>3), i); s->last_buf_size=i; @@ -1561,12 +1562,12 @@ static int mp_decode_frame(MPADecodeContext *s, OUT_INT **samples, av_log(s->avctx, AV_LOG_ERROR, "invalid old backstep %d\n", i); s->gb = s->in_gb; s->in_gb.buffer = NULL; + s->extrasize = 0; } align_get_bits(&s->gb); assert((get_bits_count(&s->gb) & 7) == 0); - i = get_bits_left(&s->gb) >> 3; - + i = (get_bits_left(&s->gb) >> 3) - s->extrasize; if (i < 0 || i > BACKSTEP_SIZE || nb_frames < 0) { if (i < 0) av_log(s->avctx, AV_LOG_ERROR, "invalid new backstep %d\n", i); _______________________________________________ libav-commits mailing list [email protected] https://lists.libav.org/mailman/listinfo/libav-commits
