@@ -95,6 +95,8 @@ typedef struct {

     uint32_t bit_rate;

     uint8_t channels;

     uint16_t frame_size;

+    int center_mix_level;                   ///< Center mix level index

+    int surround_mix_level;                 ///< Surround mix level index

     /** @} */

 } AC3HeaderInfo;

@@ -33,51 +33,64 @@ static const uint8_t eac3_blocks[4] = {

     1, 2, 3, 6

 };

+/**

+ * Table for center mix levels

+ * reference: Section 5.4.2.4 cmixlev

+ */

+static const uint8_t center_levels[4] = { 2, 3, 4, 3 };

+

+/**

+ * Table for surround mix levels

+ * reference: Section 5.4.2.5 surmixlev

+ */

+static const uint8_t surround_levels[4] = { 2, 4, 0, 4 };

-int ff_ac3_parse_header(const uint8_t buf[7], AC3HeaderInfo *hdr)

+

+int ff_ac3_parse_header(GetBitContext *gbc, AC3HeaderInfo *hdr)

 {

-    GetBitContext gbc;

     int frame_size_code;

     int num_blocks;

     memset(hdr, 0, sizeof(*hdr));

-    init_get_bits(&gbc, buf, 54);

-

-    hdr->sync_word = get_bits(&gbc, 16);

+    hdr->sync_word = get_bits(gbc, 16);

     if(hdr->sync_word != 0x0B77)

         return AC3_PARSE_ERROR_SYNC;

     /* read ahead to bsid to distinguish between AC-3 and E-AC-3 */

-    hdr->bitstream_id = show_bits_long(&gbc, 29) & 0x1F;

+    hdr->bitstream_id = show_bits_long(gbc, 29) & 0x1F;

     if(hdr->bitstream_id > 16)

         return AC3_PARSE_ERROR_BSID;

     if(hdr->bitstream_id <= 10) {

         /* Normal AC-3 */

-        hdr->crc1 = get_bits(&gbc, 16);

-        hdr->sr_code = get_bits(&gbc, 2);

+        hdr->crc1 = get_bits(gbc, 16);

+        hdr->sr_code = get_bits(gbc, 2);

         if(hdr->sr_code == 3)

             return AC3_PARSE_ERROR_SAMPLE_RATE;

-        frame_size_code = get_bits(&gbc, 6);

+        frame_size_code = get_bits(gbc, 6);

         if(frame_size_code > 37)

             return AC3_PARSE_ERROR_FRAME_SIZE;

-        skip_bits(&gbc, 5); // skip bsid, already got it

+        skip_bits(gbc, 5); // skip bsid, already got it

+

+        skip_bits(gbc, 3); // skip bitstream mode

+        hdr->channel_mode = get_bits(gbc, 3);

+

+        /* set default mix levels */

+        hdr->center_mix_level   = 3;  // -4.5dB

+        hdr->surround_mix_level = 4;  // -6.0dB

-        skip_bits(&gbc, 3); // skip bitstream mode

-        hdr->channel_mode = get_bits(&gbc, 3);

-        if((hdr->channel_mode & 1) && hdr->channel_mode != AC3_CHMODE_MONO) {

-            skip_bits(&gbc, 2); // skip center mix level

-        }

-        if(hdr->channel_mode & 4) {

-            skip_bits(&gbc, 2); // skip surround mix level

-        }

         if(hdr->channel_mode == AC3_CHMODE_STEREO) {

-            skip_bits(&gbc, 2); // skip dolby surround mode

+            skip_bits(gbc, 2); // skip dsurmod

+        } else {

+            if((hdr->channel_mode & 1) && hdr->channel_mode != AC3_CHMODE_MONO)

+                hdr->center_mix_level = center_levels[get_bits(gbc, 2)];

+            if(hdr->channel_mode & 4)

+                hdr->surround_mix_level = surround_levels[get_bits(gbc, 2)];

         }

-        hdr->lfe_on = get_bits1(&gbc);

+        hdr->lfe_on = get_bits1(gbc);

         hdr->sr_shift = FFMAX(hdr->bitstream_id, 8) - 8;

         hdr->sample_rate = ff_ac3_sample_rate_tab[hdr->sr_code] >> hdr->sr_shift;

@@ -88,32 +101,32 @@ int ff_ac3_parse_header(const uint8_t buf[7], AC3HeaderInfo *hdr)

     } else {

         /* Enhanced AC-3 */

         hdr->crc1 = 0;

-        hdr->frame_type = get_bits(&gbc, 2);

+        hdr->frame_type = get_bits(gbc, 2);

         if(hdr->frame_type == EAC3_FRAME_TYPE_RESERVED)

             return AC3_PARSE_ERROR_FRAME_TYPE;

-        skip_bits(&gbc, 3); // skip substream id

+        skip_bits(gbc, 3); // skip substream id

-        hdr->frame_size = (get_bits(&gbc, 11) + 1) << 1;

+        hdr->frame_size = (get_bits(gbc, 11) + 1) << 1;

         if(hdr->frame_size < AC3_HEADER_SIZE)

             return AC3_PARSE_ERROR_FRAME_SIZE;

-        hdr->sr_code = get_bits(&gbc, 2);

+        hdr->sr_code = get_bits(gbc, 2);

         if (hdr->sr_code == 3) {

-            int sr_code2 = get_bits(&gbc, 2);

+            int sr_code2 = get_bits(gbc, 2);

             if(sr_code2 == 3)

                 return AC3_PARSE_ERROR_SAMPLE_RATE;

             hdr->sample_rate = ff_ac3_sample_rate_tab[sr_code2] / 2;

             hdr->sr_shift = 1;

             num_blocks = 6;

         } else {

-            num_blocks = eac3_blocks[get_bits(&gbc, 2)];

+            num_blocks = eac3_blocks[get_bits(gbc, 2)];

             hdr->sample_rate = ff_ac3_sample_rate_tab[hdr->sr_code];

             hdr->sr_shift = 0;

         }

-        hdr->channel_mode = get_bits(&gbc, 3);

-        hdr->lfe_on = get_bits1(&gbc);

+        hdr->channel_mode = get_bits(gbc, 3);

+        hdr->lfe_on = get_bits1(gbc);

         hdr->bit_rate = (uint32_t)(8.0 * hdr->frame_size * hdr->sample_rate /

                         (num_blocks * 256.0));

@@ -129,8 +142,10 @@ static int ac3_sync(uint64_t state, AACAC3ParseContext *hdr_info,

     int err;

     uint64_t tmp = be2me_64(state);

     AC3HeaderInfo hdr;

+    GetBitContext gbc;

-    err = ff_ac3_parse_header(((uint8_t *)&tmp)+8-AC3_HEADER_SIZE, &hdr);

+    init_get_bits(&gbc, ((uint8_t *)&tmp)+8-AC3_HEADER_SIZE, 54);

+    err = ff_ac3_parse_header(&gbc, &hdr);

     if(err < 0)

         return 0;

@@ -24,6 +24,7 @@

 #define FFMPEG_AC3_PARSER_H

 #include "ac3.h"

+#include "bitstream.h"

 typedef enum {

     AC3_PARSE_ERROR_SYNC        = -1,

@@ -37,12 +38,12 @@ typedef enum {

  * Parses AC-3 frame header.

  * Parses the header up to the lfeon element, which is the first 52 or 54 bits

  * depending on the audio coding mode.

- * @param buf[in] Array containing the first 7 bytes of the frame.

+ * @param gbc[in] BitContext containing the first 54 bits of the frame.

  * @param hdr[out] Pointer to struct where header info is written.

  * @return Returns 0 on success, -1 if there is a sync word mismatch,

  * -2 if the bsid (version) element is invalid, -3 if the fscod (sample rate)

  * element is invalid, or -4 if the frmsizecod (bit rate) element is invalid.

  */

-int ff_ac3_parse_header(const uint8_t buf[7], AC3HeaderInfo *hdr);

+int ff_ac3_parse_header(GetBitContext *gbc, AC3HeaderInfo *hdr);

 #endif /* FFMPEG_AC3_PARSER_H */

@@ -89,18 +89,6 @@ static const float gain_levels[6] = {

 };

 /**

- * Table for center mix levels

- * reference: Section 5.4.2.4 cmixlev

- */

-static const uint8_t center_levels[4] = { 2, 3, 4, 3 };

-

-/**

- * Table for surround mix levels

- * reference: Section 5.4.2.5 surmixlev

- */

-static const uint8_t surround_levels[4] = { 2, 4, 0, 4 };

-

-/**

  * Table for default stereo downmixing coefficients

  * reference: Section 7.8.2 Downmixing Into Two Channels

  */

@@ -315,7 +303,7 @@ static int ac3_parse_header(AC3DecodeContext *s)

     GetBitContext *gbc = &s->gbc;

     int err, i;

-    err = ff_ac3_parse_header(gbc->buffer, &hdr);

+    err = ff_ac3_parse_header(gbc, &hdr);

     if(err)

         return err;

@@ -333,6 +321,8 @@ static int ac3_parse_header(AC3DecodeContext *s)

     s->fbw_channels                 = s->channels - s->lfe_on;

     s->lfe_ch                       = s->fbw_channels + 1;

     s->frame_size                   = hdr.frame_size;

+    s->center_mix_level             = hdr.center_mix_level;

+    s->surround_mix_level           = hdr.surround_mix_level;

     /* set default output to all source channels */

     s->out_channels = s->channels;

@@ -340,25 +330,6 @@ static int ac3_parse_header(AC3DecodeContext *s)

     if(s->lfe_on)

         s->output_mode |= AC3_OUTPUT_LFEON;

-    /* set default mix levels */

-    s->center_mix_level   = 3;  // -4.5dB

-    s->surround_mix_level = 4;  // -6.0dB

-

-    /* skip over portion of header which has already been read */

-    skip_bits(gbc, 16); // skip the sync_word

-    skip_bits(gbc, 16); // skip crc1

-    skip_bits(gbc, 8);  // skip fscod and frmsizecod

-    skip_bits(gbc, 11); // skip bsid, bsmod, and acmod

-    if(s->channel_mode == AC3_CHMODE_STEREO) {

-        skip_bits(gbc, 2); // skip dsurmod

-    } else {

-        if((s->channel_mode & 1) && s->channel_mode != AC3_CHMODE_MONO)

-            s->center_mix_level = center_levels[get_bits(gbc, 2)];

-        if(s->channel_mode & 4)

-            s->surround_mix_level = surround_levels[get_bits(gbc, 2)];

-    }

-    skip_bits1(gbc); // skip lfeon

-

     /* read the rest of the bsi. read twice for dual mono mode. */

     i = !(s->channel_mode);

     do {

@@ -23,6 +23,7 @@

 #include "ac3_parser.h"

 #include "raw.h"

 #include "crc.h"

+#include "bitstream.h"

 #ifdef CONFIG_MUXERS

 /* simple formats */

@@ -419,6 +420,7 @@ static int ac3_probe(AVProbeData *p)

     int max_frames, first_frames = 0, frames;

     uint8_t *buf, *buf2, *end;

     AC3HeaderInfo hdr;

+    GetBitContext gbc;

     max_frames = 0;

     buf = p->buf;

@@ -428,7 +430,8 @@ static int ac3_probe(AVProbeData *p)

         buf2 = buf;

         for(frames = 0; buf2 < end; frames++) {

-            if(ff_ac3_parse_header(buf2, &hdr) < 0)

+            init_get_bits(&gbc, buf2, 54);

+            if(ff_ac3_parse_header(&gbc, &hdr) < 0)

                 break;

             if(buf2 + hdr.frame_size > end ||

                av_crc(av_crc_get_table(AV_CRC_16_ANSI), 0, buf2 + 2, hdr.frame_size - 2))