[FFmpeg-cvslog] Decode XBR extension in first asset
Nick Brereton
git at videolan.org
Mon May 7 18:59:17 CEST 2012
ffmpeg | branch: master | Nick Brereton <nick at nbrereton.net> | Thu Apr 26 15:56:08 2012 +0100| [8036a69e6b20a52a407efc04232ae5979c82cde7] | committer: Michael Niedermayer
Decode XBR extension in first asset
Reviewed-by: Benjamin Larsson <benjamin at southpole.se>
Signed-off-by: Michael Niedermayer <michaelni at gmx.at>
> http://git.videolan.org/gitweb.cgi/ffmpeg.git/?a=commit;h=8036a69e6b20a52a407efc04232ae5979c82cde7
---
libavcodec/dca.c | 183 +++++++++++++++++++++++++++++++++++++++++++++++++++++-
1 files changed, 181 insertions(+), 2 deletions(-)
diff --git a/libavcodec/dca.c b/libavcodec/dca.c
index 1d0cf3a..f40440c 100644
--- a/libavcodec/dca.c
+++ b/libavcodec/dca.c
@@ -51,12 +51,14 @@
//#define TRACE
#define DCA_PRIM_CHANNELS_MAX (7)
-#define DCA_SUBBANDS (32)
+#define DCA_SUBBANDS (64)
#define DCA_ABITS_MAX (32) /* Should be 28 */
#define DCA_SUBSUBFRAMES_MAX (4)
#define DCA_SUBFRAMES_MAX (16)
#define DCA_BLOCKS_MAX (16)
#define DCA_LFE_MAX (3)
+#define DCA_CHSETS_MAX (4)
+#define DCA_CHSET_CHANS_MAX (8)
enum DCAMode {
DCA_MONO = 0,
@@ -1564,6 +1566,166 @@ static int dca_exss_parse_asset_header(DCAContext *s)
return 0;
}
+static int dca_xbr_parse_frame(DCAContext *s)
+{
+ int scale_table_high[DCA_CHSET_CHANS_MAX][DCA_SUBBANDS][2];
+ int active_bands[DCA_CHSETS_MAX][DCA_CHSET_CHANS_MAX];
+ int abits_high[DCA_CHSET_CHANS_MAX][DCA_SUBBANDS];
+ int anctemp[DCA_CHSET_CHANS_MAX];
+ int chset_fsize[DCA_CHSETS_MAX];
+ int n_xbr_ch[DCA_CHSETS_MAX];
+ int hdr_size, num_chsets, xbr_tmode, hdr_pos;
+ int i, j, k, l, chset, chan_base;
+
+ av_log(s->avctx, AV_LOG_DEBUG, "DTS-XBR: decoding XBR extension\n");
+
+ /* get bit position of sync header */
+ hdr_pos = get_bits_count(&s->gb) - 32;
+
+ hdr_size = get_bits(&s->gb, 6) + 1;
+ num_chsets = get_bits(&s->gb, 2) + 1;
+
+ for(i = 0; i < num_chsets; i++)
+ chset_fsize[i] = get_bits(&s->gb, 14) + 1;
+
+ xbr_tmode = get_bits1(&s->gb);
+
+ for(i = 0; i < num_chsets; i++) {
+ n_xbr_ch[i] = get_bits(&s->gb, 3) + 1;
+ k = get_bits(&s->gb, 2) + 5;
+ for(j = 0; j < n_xbr_ch[i]; j++)
+ active_bands[i][j] = get_bits(&s->gb, k) + 1;
+ }
+
+ /* skip to the end of the header */
+ i = get_bits_count(&s->gb);
+ if(hdr_pos + hdr_size * 8 > i)
+ skip_bits_long(&s->gb, hdr_pos + hdr_size * 8 - i);
+
+ /* loop over the channel data sets */
+ /* only decode as many channels as we've decoded base data for */
+ for(chset = 0, chan_base = 0;
+ chset < num_chsets && chan_base + n_xbr_ch[chset] <= s->prim_channels;
+ chan_base += n_xbr_ch[chset++]) {
+ int start_posn = get_bits_count(&s->gb);
+ int subsubframe = 0;
+ int subframe = 0;
+
+ /* loop over subframes */
+ for (k = 0; k < (s->sample_blocks / 8); k++) {
+ /* parse header if we're on first subsubframe of a block */
+ if(subsubframe == 0) {
+ /* Parse subframe header */
+ for(i = 0; i < n_xbr_ch[chset]; i++) {
+ anctemp[i] = get_bits(&s->gb, 2) + 2;
+ }
+
+ for(i = 0; i < n_xbr_ch[chset]; i++) {
+ get_array(&s->gb, abits_high[i], active_bands[chset][i], anctemp[i]);
+ }
+
+ for(i = 0; i < n_xbr_ch[chset]; i++) {
+ anctemp[i] = get_bits(&s->gb, 3);
+ if(anctemp[i] < 1) {
+ av_log(s->avctx, AV_LOG_ERROR, "DTS-XBR: SYNC ERROR\n");
+ return AVERROR_INVALIDDATA;
+ }
+ }
+
+ /* generate scale factors */
+ for(i = 0; i < n_xbr_ch[chset]; i++) {
+ const uint32_t *scale_table;
+ int nbits;
+
+ if (s->scalefactor_huffman[chan_base+i] == 6) {
+ scale_table = scale_factor_quant7;
+ } else {
+ scale_table = scale_factor_quant6;
+ }
+
+ nbits = anctemp[i];
+
+ for(j = 0; j < active_bands[chset][i]; j++) {
+ if(abits_high[i][j] > 0) {
+ scale_table_high[i][j][0] =
+ scale_table[get_bits(&s->gb, nbits)];
+
+ if(xbr_tmode && s->transition_mode[i][j]) {
+ scale_table_high[i][j][1] =
+ scale_table[get_bits(&s->gb, nbits)];
+ }
+ }
+ }
+ }
+ }
+
+ /* decode audio array for this block */
+ for(i = 0; i < n_xbr_ch[chset]; i++) {
+ for(j = 0; j < active_bands[chset][i]; j++) {
+ const int xbr_abits = abits_high[i][j];
+ const float quant_step_size = lossless_quant_d[xbr_abits];
+ const int sfi = xbr_tmode && s->transition_mode[i][j] && subsubframe >= s->transition_mode[i][j];
+ const float rscale = quant_step_size * scale_table_high[i][j][sfi];
+ float *subband_samples = s->subband_samples[k][chan_base+i][j];
+ int block[8];
+
+ if(xbr_abits <= 0)
+ continue;
+
+ if(xbr_abits > 7) {
+ get_array(&s->gb, block, 8, xbr_abits - 3);
+ } else {
+ int block_code1, block_code2, size, levels, err;
+
+ size = abits_sizes[xbr_abits - 1];
+ levels = abits_levels[xbr_abits - 1];
+
+ block_code1 = get_bits(&s->gb, size);
+ block_code2 = get_bits(&s->gb, size);
+ err = decode_blockcodes(block_code1, block_code2,
+ levels, block);
+ if (err) {
+ av_log(s->avctx, AV_LOG_ERROR,
+ "ERROR: DTS-XBR: block code look-up failed\n");
+ return AVERROR_INVALIDDATA;
+ }
+ }
+
+ /* scale & sum into subband */
+ for(l = 0; l < 8; l++)
+ subband_samples[l] += (float)block[l] * rscale;
+ }
+ }
+
+ /* check DSYNC marker */
+ if(s->aspf || subsubframe == s->subsubframes[subframe] - 1) {
+ if(get_bits(&s->gb, 16) != 0xffff) {
+ av_log(s->avctx, AV_LOG_ERROR, "DTS-XBR: Didn't get subframe DSYNC\n");
+ return AVERROR_INVALIDDATA;
+ }
+ }
+
+ /* advance sub-sub-frame index */
+ if(++subsubframe >= s->subsubframes[subframe]) {
+ subsubframe = 0;
+ subframe++;
+ }
+ }
+
+ /* skip to next channel set */
+ i = get_bits_count(&s->gb);
+ if(start_posn + chset_fsize[chset] * 8 != i) {
+ j = start_posn + chset_fsize[chset] * 8 - i;
+ if(j < 0 || j >= 8)
+ av_log(s->avctx, AV_LOG_ERROR, "DTS-XBR: end of channel set,"
+ " skipping further than expected (%d bits)\n", j);
+ skip_bits_long(&s->gb, j);
+ }
+ }
+
+ return 0;
+}
+
/**
* Parse extension substream header (HD)
*/
@@ -1575,15 +1737,20 @@ static void dca_exss_parse_header(DCAContext *s)
int num_assets = 1;
int active_ss_mask[8];
int i, j;
+ int start_posn;
+ int hdrsize;
+ uint32_t mkr;
if (get_bits_left(&s->gb) < 52)
return;
+ start_posn = get_bits_count(&s->gb) - 32;
+
skip_bits(&s->gb, 8); // user data
ss_index = get_bits(&s->gb, 2);
blownup = get_bits1(&s->gb);
- skip_bits(&s->gb, 8 + 4 * blownup); // header_size
+ hdrsize = get_bits(&s->gb, 8 + 4 * blownup) + 1; // header_size
skip_bits(&s->gb, 16 + 4 * blownup); // hd_size
s->static_fields = get_bits1(&s->gb);
@@ -1644,6 +1811,18 @@ static void dca_exss_parse_header(DCAContext *s)
/* not parsed further, we were only interested in the extensions mask
* from the asset header */
+
+ if(num_assets > 0) {
+ j = get_bits_count(&s->gb);
+ if(start_posn + hdrsize * 8 > j)
+ skip_bits_long(&s->gb, start_posn + hdrsize * 8 - j);
+
+ /* check first asset for XBR -- should also check extension mask! */
+ mkr = get_bits_long(&s->gb, 32);
+
+ if(mkr == 0x655e315e)
+ dca_xbr_parse_frame(s);
+ }
}
/**
More information about the ffmpeg-cvslog
mailing list