Author: faust3 Date: Sat Aug 29 17:27:47 2009 New Revision: 5337 Log: update channel context and estimate new min_channel_len in one loop use an array instead of a bit mask to decide if a channel contains a subframe Modified: wmapro/wmaprodec.c Modified: wmapro/wmaprodec.c ============================================================================== --- wmapro/wmaprodec.c Sat Aug 29 16:58:33 2009 (r5336) +++ wmapro/wmaprodec.c Sat Aug 29 17:27:47 2009 (r5337) @@ -527,6 +527,7 @@ static int decode_tilehdr(WMA3DecodeCont } } else { /** different channels have different subframe layouts */ uint16_t num_samples[WMAPRO_MAX_CHANNELS]; + uint8_t decode_channel[WMAPRO_MAX_CHANNELS]; int channels_for_cur_subframe = s->num_channels; int min_channel_len = 0; @@ -534,33 +535,29 @@ static int decode_tilehdr(WMA3DecodeCont /** loop until the frame data is split between the subframes */ do { - unsigned int channel_mask = 0; int subframe_len; - /** For every channel with the minimum length, 1 bit - might be transmitted that informs us if the channel - contains a subframe with the next subframe_len. */ - if (channels_for_cur_subframe == 1 || (min_channel_len == s->samples_per_frame - s->min_samples_per_subframe)) { - channel_mask = -1; - } else { - channel_mask = get_bits(&s->gb, channels_for_cur_subframe); - if (!channel_mask) { - av_log(s->avctx, AV_LOG_ERROR, - "broken frame: zero frames for subframe_len\n"); - return AVERROR_INVALIDDATA; - } + /** check which channels contain the subframe */ + for (c = 0; c < s->num_channels; c++) { + if (num_samples[c] == min_channel_len) { + if (channels_for_cur_subframe == 1 || (min_channel_len == s->samples_per_frame - s->min_samples_per_subframe)) + decode_channel[c] = 1; + else + decode_channel[c] = get_bits1(&s->gb); + } else + decode_channel[c] = 0; } + /** get subframe length */ if (!(subframe_len = decode_subframe_length(s, min_channel_len))) return AVERROR_INVALIDDATA; + /** add subframes to the individual channels and find new min_channel_len */ + min_channel_len += subframe_len; for (c = 0; c < s->num_channels; c++) { WMA3ChannelCtx* chan = &s->channel[c]; - /** add subframes to the individual channels */ - if (min_channel_len == num_samples[c]) { - --channels_for_cur_subframe; - if (channel_mask & (1 << channels_for_cur_subframe)) { + if (decode_channel[c]) { if (chan->num_subframes >= MAX_SUBFRAMES) { av_log(s->avctx, AV_LOG_ERROR, "broken frame: num subframes > 31\n"); @@ -574,14 +571,7 @@ static int decode_tilehdr(WMA3DecodeCont "channel len > samples_per_frame\n"); return AVERROR_INVALIDDATA; } - } - } - } - - min_channel_len = s->samples_per_frame; - /** find channels with the smallest overall length */ - for (c = 0; c < s->num_channels; c++) { - if (num_samples[c] <= min_channel_len) { + } else if(num_samples[c] <= min_channel_len) { if (num_samples[c] < min_channel_len) { channels_for_cur_subframe = 0; min_channel_len = num_samples[c];