mp3 parser: fix seeking to end of frame; new corrupted frame heuristic

1 files changed, 37 insertions, 41 deletions

diff --git a/plugins/mpgmad/mpgmad.c b/plugins/mpgmad/mpgmad.c
index 87761bb6..dab3fd87 100644
--- a/plugins/mpgmad/mpgmad.c
+++ b/plugins/mpgmad/mpgmad.c
@@ -190,6 +190,8 @@ static int
 cmp3_scan_stream (buffer_t *buffer, int sample) {
     trace ("cmp3_scan_stream %d (offs: %lld)\n", sample, deadbeef->ftell (buffer->file));
 
+    int have_info = 0;
+
 // {{{ prepare for scan - seek, reset averages, etc
     int initpos = deadbeef->ftell (buffer->file);
     trace ("initpos: %d\n", initpos);
@@ -198,10 +200,8 @@ cmp3_scan_stream (buffer_t *buffer, int sample) {
     int scansamples = 0;
     buffer->currentsample = 0;
     buffer->skipsamples = 0;
-//    int avg_bitrate = 0;
     int valid_frames = 0;
     int prev_bitrate = -1;
-    buffer->samplerate = 0;
     int64_t fsize = deadbeef->fgetlength (buffer->file);
 
     if (sample <= 0) {
@@ -223,7 +223,6 @@ cmp3_scan_stream (buffer_t *buffer, int sample) {
         buffer->startoffset = initpos;
     }
 
-    int had_invalid_frames = 0;
     int lastframe_valid = 0;
     int64_t offs = -1;
 // }}}
@@ -241,12 +240,6 @@ cmp3_scan_stream (buffer_t *buffer, int sample) {
 // {{{ parse frame header, sync stream
         // mp3 files often have some garbage in the beginning
         // try to skip it if this is the case
-        if (!lastframe_valid && valid_frames > 5) {
-            had_invalid_frames = 1;
-        }
-        if (!lastframe_valid && offs >= 0) {
-            deadbeef->fseek (buffer->file, offs+1, SEEK_SET);
-        }
         offs = deadbeef->ftell (buffer->file);
         //uint8_t fb[4+2+2]; // 4b frame header + 2b crc + 2b sideinfo main_data_begin
         uint8_t fb[4]; // just the header
@@ -257,16 +250,16 @@ cmp3_scan_stream (buffer_t *buffer, int sample) {
         uint32_t hdr;
         uint8_t sync = fb[0];
         if (sync != 0xff) {
-//            trace ("[1]frame %d didn't seek to frame end\n", nframe);
             lastframe_valid = 0;
+//            trace ("[1]frame %d didn't seek to frame end\n", nframe);
             continue; // not an mpeg frame
         }
         else {
             // 2nd sync byte
             sync = fb[1];
             if ((sync >> 5) != 7) {
-//                trace ("[2]frame %d didn't seek to frame end\n", nframe);
                 lastframe_valid = 0;
+  //              trace ("[2]frame %d didn't seek to frame end\n", nframe);
                 continue;
             }
         }
@@ -290,8 +283,8 @@ cmp3_scan_stream (buffer_t *buffer, int sample) {
         int ver = (hdr & (3<<19)) >> 19;
         ver = vertbl[ver];
         if (ver < 0) {
-            trace ("frame %d bad mpeg version %d\n", nframe, (hdr & (3<<19)) >> 19);
             lastframe_valid = 0;
+            trace ("frame %d bad mpeg version %d\n", nframe, (hdr & (3<<19)) >> 19);
             continue; // invalid frame
         }
 
@@ -300,8 +293,8 @@ cmp3_scan_stream (buffer_t *buffer, int sample) {
         int layer = (hdr & (3<<17)) >> 17;
         layer = ltbl[layer];
         if (layer < 0) {
-            trace ("frame %d bad layer %d\n", nframe, (hdr & (3<<17)) >> 17);
             lastframe_valid = 0;
+            trace ("frame %d bad layer %d\n", nframe, (hdr & (3<<17)) >> 17);
             continue; // invalid frame
         }
 
@@ -326,8 +319,8 @@ cmp3_scan_stream (buffer_t *buffer, int sample) {
         }
         bitrate = brtable[idx][bitrate];
         if (bitrate <= 0) {
-            trace ("frame %d bad bitrate %d\n", nframe, (hdr & (0x0f<<12)) >> 12);
             lastframe_valid = 0;
+            trace ("frame %d bad bitrate %d\n", nframe, (hdr & (0x0f<<12)) >> 12);
             continue; // invalid frame
         }
 
@@ -340,8 +333,8 @@ cmp3_scan_stream (buffer_t *buffer, int sample) {
         int samplerate = (hdr & (0x03<<10))>>10;
         samplerate = srtable[ver-1][samplerate];
         if (samplerate < 0) {
-            trace ("frame %d bad samplerate %d\n", nframe, (hdr & (0x03<<10))>>10);
             lastframe_valid = 0;
+            trace ("frame %d bad samplerate %d\n", nframe, (hdr & (0x03<<10))>>10);
             continue; // invalid frame
         }
 
@@ -355,13 +348,13 @@ cmp3_scan_stream (buffer_t *buffer, int sample) {
         // check if channel/bitrate combination is valid for layer2
         if (layer == 2) {
             if ((bitrate <= 56 || bitrate == 80) && nchannels != 1) {
-                trace ("mpgmad: bad frame %d: layer %d, channels %d, bitrate %d\n", nframe, layer, nchannels, bitrate);
                 lastframe_valid = 0;
+                trace ("mpgmad: bad frame %d: layer %d, channels %d, bitrate %d\n", nframe, layer, nchannels, bitrate);
                 continue; // bad frame
             }
             if (bitrate >= 224 && nchannels == 1) {
-                trace ("mpgmad: bad frame %d: layer %d, channels %d, bitrate %d\n", nframe, layer, nchannels, bitrate);
                 lastframe_valid = 0;
+                trace ("mpgmad: bad frame %d: layer %d, channels %d, bitrate %d\n", nframe, layer, nchannels, bitrate);
                 continue; // bad frame
             }
         }
@@ -396,13 +389,13 @@ cmp3_scan_stream (buffer_t *buffer, int sample) {
                 }
             }
             packetlength = samples_per_frame / 8 * bitrate / samplerate + padding;
-//            if (sample > 0) {
-//                printf ("frame: %d, crc: %d, layer: %d, bitrate: %d, samplerate: %d, filepos: 0x%llX, dataoffs: 0x%X, size: 0x%X\n", nframe, prot, layer, bitrate, samplerate, deadbeef->ftell (buffer->file)-8, data_ptr, packetlength);
-//            }
+            if (sample > 0) {
+                trace ("frame: %d, layer: %d, bitrate: %d, samplerate: %d\n", nframe, layer, bitrate, samplerate);
+            }
         }
         else {
-            trace ("frame %d samplerate or bitrate is invalid\n", nframe);
             lastframe_valid = 0;
+            trace ("frame %d samplerate or bitrate is invalid\n", nframe);
             continue;
         }
 // }}}
@@ -417,27 +410,25 @@ cmp3_scan_stream (buffer_t *buffer, int sample) {
         valid_frames++;
 
 // {{{ update stream parameters, only when sample!=0 or 1st frame
-        if (sample != 0 || nframe == 0)
+//        trace ("have_info: %d, lastframe_valid=%d\n", have_info, lastframe_valid);
+        if (!have_info && lastframe_valid)
         {
-            if (sample == 0 && lastframe_valid) {
-                return 0;
-            }
             // don't get parameters from frames coming after any bad frame
-            if (!had_invalid_frames) {
-                buffer->version = ver;
-                buffer->layer = layer;
-                buffer->bitrate = bitrate;
-                buffer->samplerate = samplerate;
-                buffer->packetlength = packetlength;
-                if (nchannels > buffer->channels) {
-                    buffer->channels = nchannels;
-                }
-                buffer->bitspersample = 16;
-//                trace ("frame %d mpeg v%d layer %d bitrate %d samplerate %d packetlength %d channels %d\n", nframe, ver, layer, bitrate, samplerate, packetlength, nchannels);
+            trace ("\033[0;31mgot info!\033[37;0m\n");
+            have_info = 1;
+            buffer->version = ver;
+            buffer->layer = layer;
+            buffer->bitrate = bitrate;
+            buffer->samplerate = samplerate;
+            buffer->packetlength = packetlength;
+            if (nchannels > buffer->channels) {
+                buffer->channels = nchannels;
             }
+            buffer->bitspersample = 16;
+            trace ("frame %d mpeg v%d layer %d bitrate %d samplerate %d packetlength %d channels %d\n", nframe, ver, layer, bitrate, samplerate, packetlength, nchannels);
         }
 // }}}
-
+        //trace ("lastframe_valid=1, valid_frames=%d, sample=%d, nframe=%d\n", valid_frames, sample, nframe);
         lastframe_valid = 1;
 
         int64_t framepos = deadbeef->ftell (buffer->file)-(int)sizeof(fb);
@@ -612,6 +603,7 @@ cmp3_scan_stream (buffer_t *buffer, int sample) {
 
                     if (sample == 0) {
                         deadbeef->fseek (buffer->file, framepos, SEEK_SET);
+                        trace ("scan finished\n");
                         return 0;
                     }
                 }
@@ -656,7 +648,7 @@ cmp3_scan_stream (buffer_t *buffer, int sample) {
         scansamples += samples_per_frame;
         nframe++;
         if (packetlength > 0) {
-            deadbeef->fseek (buffer->file, packetlength-(int)sizeof(fb), SEEK_CUR);
+            deadbeef->fseek (buffer->file, framepos+packetlength, SEEK_SET);
         }
     }
 end_scan:
@@ -664,7 +656,7 @@ end_scan:
         trace ("cmp3_scan_stream: couldn't find mpeg frames in file\n");
         return -1;
     }
-    if (sample == 0) {
+    if (sample == 0 && have_info) {
 // {{{ calculate final averages
         buffer->avg_packetlength /= (float)valid_frames;
         buffer->avg_samplerate /= valid_frames;
@@ -679,14 +671,18 @@ end_scan:
             buffer->duration = (buffer->totalsamples - buffer->delay - buffer->padding) / buffer->avg_samplerate;
         }
         buffer->bitrate = (fsize-buffer->startoffset-buffer->endoffset) / buffer->duration * 8;
-        trace ("nframes: %d, fsize: %lld, spf: %d, smp: %d, totalsamples: %d\n", buffer->nframes, fsize, buffer->avg_samples_per_frame, buffer->avg_samplerate, buffer->totalsamples);
+        trace ("nframes: %d, fsize: %lld, spf: %d, smp: %d, totalsamples: %d, real_smp: %d\n", buffer->nframes, fsize, buffer->avg_samples_per_frame, buffer->avg_samplerate, buffer->totalsamples, buffer->samplerate);
 // }}}
         return 0;
     }
 
+    if (buffer->samplerate <= 0) {
+        trace ("invalid samplerate\n");
+        return -1;
+    }
     buffer->totalsamples = scansamples;
     buffer->duration = (buffer->totalsamples - buffer->delay - buffer->padding) / buffer->samplerate;
-//    printf ("nframes=%d, totalsamples=%d, samplerate=%d, dur=%f\n", nframe, scansamples, buffer->samplerate, buffer->duration);
+//    trace ("nframes=%d, totalsamples=%d, samplerate=%d, dur=%f\n", nframe, scansamples, buffer->samplerate, buffer->duration);
     return 0;
 }