shithub: mp3dec

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mp3dec_ex: do not decode empty frame with vbrtag,
if it's valid, but there no frames flag, just skip it.

--- a/minimp3_ex.h

+++ b/minimp3_ex.h

@@ -191,7 +191,7 @@

         return 0;

     int flags = tag[7];

     if (!((flags & FRAMES_FLAG)))

-        return 0;

+        return -1;

     tag += 8;

     *frames = (uint32_t)(tag[0] << 24) | (tag[1] << 16) | (tag[2] << 8) | tag[3];

     tag += 4;

@@ -308,7 +308,8 @@

         frame_info.bitrate_kbps = hdr_bitrate_kbps(hdr);

         frame_info.frame_bytes = frame_size;

         samples = hdr_frame_samples(hdr)*frame_info.channels;

-        if (mp3dec_check_vbrtag(hdr, frame_size, &frames, &delay, &padding))

+        int ret = mp3dec_check_vbrtag(hdr, frame_size, &frames, &delay, &padding);

+        if (ret > 0)

         {

             padding *= frame_info.channels;

             to_skip = delay*frame_info.channels;

@@ -319,6 +320,9 @@

                 detected_samples -= padding;

             if (!detected_samples)

                 return 0;

+        }

+        if (ret)

+        {

             if (io)

             {

                 consumed += frame_size;

@@ -552,7 +556,10 @@

         dec->start_offset = dec->offset = offset;

         dec->end_offset   = offset + buf_size;

         dec->free_format_bytes = free_format_bytes; /* should not change */

-        if (mp3dec_check_vbrtag(frame, frame_size, &frames, &delay, &padding))

+        int ret = mp3dec_check_vbrtag(frame, frame_size, &frames, &delay, &padding);

+        if (ret)

+            dec->start_offset = dec->offset = offset + frame_size;

+        if (ret > 0)

         {

             padding *= info->channels;

             dec->start_delay = dec->to_skip = delay*info->channels;

@@ -562,10 +569,10 @@

             if (padding > 0 && dec->samples >= (uint64_t)padding)

                 dec->samples -= padding;

             dec->detected_samples = dec->samples;

-            dec->start_offset = dec->offset = offset + frame_size;

             dec->vbr_tag_found = 1;

             return MP3D_E_USER;

-        }

+        } else if (ret < 0)

+            return 0;

     }

     if (dec->index.num_frames + 1 > dec->index.capacity)

     {

--- a/scripts/build.sh

+++ b/scripts/build.sh

@@ -95,6 +95,10 @@

 [[ "$(./minimp3 -m 8 -s 1 -e 5 vectors/l3-nonstandard-vbrtag-only.bit)" != "error: mp3dec_ex_seek()=-3 failed" ]] && echo fail && exit 1 || echo pass

 [[ "$(./minimp3 -m 6 -s 1 -f 2 vectors/l3-nonstandard-sin1k0db_lame_vbrtag.bit)" != "error: mp3dec_ex_seek()=-2 failed" ]] && echo fail && exit 1 || echo pass

 [[ "$(./minimp3 vectors/l3-nonstandard-vbrtag-empty.bit)" != "rate=0 samples=0 max_diff=0 PSNR=99.000000" ]] && echo fail && exit 1 || echo pass

+# Currently vbrtag with no frames flag treated as no vbrtag, not sure if any software produce such files.

+# Delay and padding usage can be implemented if such software/files exists.

+[[ "$(./minimp3 vectors/l3-nonstandard-vbrtag-noframes.bit)" != "rate=44100 samples=0 max_diff=0 PSNR=99.000000" ]] && echo fail && exit 1 || echo pass

+[[ "$(./minimp3 -m 6 vectors/l3-nonstandard-vbrtag-noframes.bit)" != "rate=44100 samples=0 max_diff=0 PSNR=99.000000" ]] && echo fail && exit 1 || echo pass

 set -e

 ./minimp3 -m 6 -s 215 -b vectors/l3-sin1k0db.bit vectors/l3-sin1k0db.pcm

binary files /dev/null b/vectors/l3-nonstandard-vbrtag-noframes.bit differ