Author: faust3 Date: Sat Aug 29 16:26:24 2009 New Revision: 5333 Log: unify subframe length decoding for the case when the last subframe has the minimum length Modified: wmapro/wmaprodec.c Modified: wmapro/wmaprodec.c ============================================================================== --- wmapro/wmaprodec.c Sat Aug 29 15:54:31 2009 (r5332) +++ wmapro/wmaprodec.c Sat Aug 29 16:26:24 2009 (r5333) @@ -449,13 +449,19 @@ static av_cold int decode_init(AVCodecCo /** *@brief Decode the subframe length. *@param s context + *@param offset sample offset in the frame *@return decoded subframe length on success, 0 in case of an error */ -static int decode_subframe_length(WMA3DecodeContext *s) +static int decode_subframe_length(WMA3DecodeContext *s, int offset) { int log2_subframe_len = 0; int subframe_len; - /* 1 bit indicates if the subframe is of maximum length */ + + /** no need to read from the bitstream when only one length is possible */ + if (offset == s->samples_per_frame - s->min_samples_per_subframe) + return s->min_samples_per_subframe; + + /** 1 bit indicates if the subframe is of maximum length */ if (s->max_subframe_len_bit) { if (get_bits1(&s->gb)) log2_subframe_len = 1 + get_bits(&s->gb, s->subframe_len_bits-1); @@ -512,11 +518,9 @@ static int decode_tilehdr(WMA3DecodeCont if (s->max_num_subframes == 1 || get_bits1(&s->gb)) { int num_samples = 0; while (num_samples < s->samples_per_frame) { - int subframe_len = s->min_samples_per_subframe; - if (num_samples < s->samples_per_frame - s->min_samples_per_subframe) { - if (!(subframe_len = decode_subframe_length(s))) - return AVERROR_INVALIDDATA; - } + int subframe_len; + if (!(subframe_len = decode_subframe_length(s, num_samples))) + return AVERROR_INVALIDDATA; for (c = 0; c < s->num_channels; c++) s->channel[c].subframe_len[s->channel[c].num_subframes++] = subframe_len; num_samples += subframe_len; @@ -563,12 +567,8 @@ static int decode_tilehdr(WMA3DecodeCont } } - /** if we have the choice get next subframe length from the - bitstream */ - if (min_samples != missing_samples) { - if (!(subframe_len = decode_subframe_length(s))) - return AVERROR_INVALIDDATA; - } + if (!(subframe_len = decode_subframe_length(s, min_channel_len))) + return AVERROR_INVALIDDATA; for (c = 0; c < s->num_channels; c++) { WMA3ChannelCtx* chan = &s->channel[c];