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[patch] Version 2 - Add looping to music_flac.c

music_flac_add_looping_v2.patch (text/plain), 10.05 KB, created by Michael Day on 2019-11-12 03:06:20 UTC

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Creator: Michael Day

Created: 2019-11-12 03:06:20 UTC

Size: 10.05 KB

patch

obsolete

>diff --git a/music_flac.c b/music_flac.c
>index fc661a9..4b13bdb 100644
>--- a/music_flac.c
>+++ b/music_flac.c
>@@ -61,6 +61,11 @@ typedef struct {
>                         FLAC__uint64 sample);
>     FLAC__StreamDecoderState (*FLAC__stream_decoder_get_state)(
>                         const FLAC__StreamDecoder *decoder);
>+    FLAC__uint64 (*FLAC__stream_decoder_get_total_samples)(
>+                        const FLAC__StreamDecoder *decoder);
>+    FLAC__bool (*FLAC__stream_decoder_set_metadata_respond)(
>+                        FLAC__StreamDecoder *decoder,
>+                        FLAC__MetadataType type);
> } flac_loader;
> 
> static flac_loader flac = {
>@@ -114,6 +119,11 @@ static int FLAC_Load(void)
>         FUNCTION_LOADER(FLAC__stream_decoder_process_until_end_of_stream, FLAC__bool (*)(FLAC__StreamDecoder *))
>         FUNCTION_LOADER(FLAC__stream_decoder_seek_absolute, FLAC__bool (*)(FLAC__StreamDecoder *, FLAC__uint64))
>         FUNCTION_LOADER(FLAC__stream_decoder_get_state, FLAC__StreamDecoderState (*)(const FLAC__StreamDecoder *decoder))
>+        FUNCTION_LOADER(FLAC__stream_decoder_get_total_samples,
>+                        FLAC__uint64 (*)(const FLAC__StreamDecoder *))
>+        FUNCTION_LOADER(FLAC__stream_decoder_set_metadata_respond,
>+                        FLAC__bool (*)(FLAC__StreamDecoder *,
>+                                       FLAC__MetadataType))
>     }
>     ++flac.loaded;
> 
>@@ -144,6 +154,12 @@ typedef struct {
>     SDL_RWops *src;
>     int freesrc;
>     SDL_AudioStream *stream;
>+    int loop;
>+    FLAC__uint64 pcm_pos;
>+    SDL_bool loop_flag;
>+    FLAC__uint64 loop_start;
>+    FLAC__uint64 loop_end;
>+    FLAC__uint64 loop_len;
> } FLAC_Music;
> 
> 
>@@ -251,7 +267,7 @@ static FLAC__StreamDecoderWriteStatus flac_write_music_cb(
>     FLAC_Music *music = (FLAC_Music *)client_data;
>     Sint16 *data;
>     unsigned int i, j, channels;
>-    int shift_amount = 0;
>+    int shift_amount = 0, amount;
> 
>     if (!music->stream) {
>         return FLAC__STREAM_DECODER_WRITE_STATUS_ABORT;
>@@ -321,41 +337,124 @@ static FLAC__StreamDecoderWriteStatus flac_write_music_cb(
>             }
>         }
>     }
>-    SDL_AudioStreamPut(music->stream, data, (frame->header.blocksize * channels * sizeof(*data)));
>+    amount = frame->header.blocksize * channels * sizeof(*data);
>+    music->pcm_pos += frame->header.blocksize;
>+    if ((music->loop == 1) && (music->pcm_pos >= music->loop_end)) {
>+        amount -= (music->pcm_pos - music->loop_end) * channels * sizeof(*data);
>+        music->loop_flag = SDL_TRUE;
>+    }
>+
>+    SDL_AudioStreamPut(music->stream, data, amount);
>     SDL_stack_free(data);
> 
>     return FLAC__STREAM_DECODER_WRITE_STATUS_CONTINUE;
> }
> 
>+/* Parse time string of the form HH:MM:SS.mmm and return equivalent sample
>+ * position */
>+static FLAC__uint64 parse_time(char *time, unsigned samplerate_hz)
>+{
>+    char *num_start, *p;
>+    FLAC__uint64 result = 0;
>+    char c;
>+
>+    /* Time is directly expressed as a sample position */
>+    if (SDL_strchr(time, ':') == NULL) {
>+        return SDL_strtoull(time, NULL, 10);
>+    }
>+
>+    result = 0;
>+    num_start = time;
>+
>+    for (p = time; *p != '\0'; ++p) {
>+        if (*p == '.' || *p == ':') {
>+            c = *p; *p = '\0';
>+            result = result * 60 + SDL_atoi(num_start);
>+            num_start = p + 1;
>+            *p = c;
>+        }
>+
>+        if (*p == '.') {
>+            return result * samplerate_hz
>+                + (FLAC__uint64) (SDL_atof(p) * samplerate_hz);
>+        }
>+    }
>+
>+    return (result * 60 + SDL_atoi(num_start)) * samplerate_hz;
>+}
>+
> static void flac_metadata_music_cb(
>                     const FLAC__StreamDecoder *decoder,
>                     const FLAC__StreamMetadata *metadata,
>                     void *client_data)
> {
>     FLAC_Music *music = (FLAC_Music *)client_data;
>+    const FLAC__StreamMetadata_VorbisComment *vc;
>     int channels;
>+    unsigned rate;
>+    char *param, *argument, *value;
>+    SDL_bool is_loop_length = SDL_FALSE;
>+
>+    if (metadata->type == FLAC__METADATA_TYPE_STREAMINFO) {
>+        music->sample_rate = metadata->data.stream_info.sample_rate;
>+        music->channels = metadata->data.stream_info.channels;
>+        music->bits_per_sample = metadata->data.stream_info.bits_per_sample;
>+    /*printf("FLAC: Sample rate = %d, channels = %d, bits_per_sample = %d\n", music->sample_rate, music->channels, music->bits_per_sample);*/
>+
>+        /* SDL's channel mapping and FLAC channel mapping are the same,
>+           except for 3 channels: SDL is FL FR LFE and FLAC is FL FR FC
>+         */
>+        if (music->channels == 3) {
>+            channels = 2;
>+        } else {
>+            channels = music->channels;
>+        }
> 
>-    if (metadata->type != FLAC__METADATA_TYPE_STREAMINFO) {
>-        return;
>-    }
>+        /* We check for NULL stream later when we get data */
>+        SDL_assert(!music->stream);
>+        music->stream = SDL_NewAudioStream(AUDIO_S16SYS, channels, music->sample_rate,
>+                                          music_spec.format, music_spec.channels, music_spec.freq);
>+    } else if (metadata->type == FLAC__METADATA_TYPE_VORBIS_COMMENT) {
>+        vc  = &metadata->data.vorbis_comment;
>+        rate = music->sample_rate;
>+
>+        for (int i = 0; i < vc->num_comments; ++i) {
>+            param = SDL_strdup(vc->comments[i].entry);
>+            argument = param;
>+            value = SDL_strchr(param, '=');
>+
>+            if (value == NULL) {
>+                value = param + SDL_strlen(param);
>+            } else {
>+                *(value++) = '\0';
>+            }
> 
>-    music->sample_rate = metadata->data.stream_info.sample_rate;
>-    music->channels = metadata->data.stream_info.channels;
>-    music->bits_per_sample = metadata->data.stream_info.bits_per_sample;
>-/*printf("FLAC: Sample rate = %d, channels = %d, bits_per_sample = %d\n", music->sample_rate, music->channels, music->bits_per_sample);*/
>+            /* Want to match LOOP-START, LOOP_START, etc. Remove - or _ from
>+             * string if it is present at position 4. */
> 
>-    /* SDL's channel mapping and FLAC channel mapping are the same,
>-       except for 3 channels: SDL is FL FR LFE and FLAC is FL FR FC
>-     */
>-    if (music->channels == 3) {
>-        channels = 2;
>-    } else {
>-        channels = music->channels;
>+            if ((argument[4] == '_') || (argument[4] == '-')) {
>+                SDL_memmove(argument + 4, argument + 5,
>+                           SDL_strlen(argument) - 4);
>+            }
>+
>+            if (SDL_strcasecmp(argument, "LOOPSTART") == 0)
>+                music->loop_start = parse_time(value, rate);
>+            else if (SDL_strcasecmp(argument, "LOOPLENGTH") == 0) {
>+                music->loop_len = SDL_strtoull(value, NULL, 10);
>+                is_loop_length = SDL_TRUE;
>+            } else if (SDL_strcasecmp(argument, "LOOPEND") == 0) {
>+                is_loop_length = SDL_FALSE;
>+                music->loop_end = parse_time(value, rate);
>+            }
>+            SDL_free(param);
>+        }
>+
>+        if (is_loop_length) {
>+            music->loop_end = music->loop_start + music->loop_len;
>+        } else {
>+            music->loop_len = music->loop_end - music->loop_start;
>+        }
>     }
>-    /* We check for NULL stream later when we get data */
>-    SDL_assert(!music->stream);
>-    music->stream = SDL_NewAudioStream(AUDIO_S16SYS, channels, music->sample_rate,
>-                                      music_spec.format, music_spec.channels, music_spec.freq);
> }
> 
> static void flac_error_music_cb(
>@@ -389,6 +488,7 @@ static void *FLAC_CreateFromRW(SDL_RWops *src, int freesrc)
>     FLAC_Music *music;
>     int init_stage = 0;
>     int was_error = 1;
>+    FLAC__uint64 full_length;
> 
>     music = (FLAC_Music *)SDL_calloc(1, sizeof(*music));
>     if (!music) {
>@@ -397,10 +497,18 @@ static void *FLAC_CreateFromRW(SDL_RWops *src, int freesrc)
>     }
>     music->src = src;
>     music->volume = MIX_MAX_VOLUME;
>+    music->loop = -1;
>+    music->loop_start = -1;
>+    music->loop_end = 0;
>+    music->loop_len = 0;
>+    music->loop_flag = SDL_FALSE;
>+    music->pcm_pos = 0;
> 
>     music->flac_decoder = flac.FLAC__stream_decoder_new();
>     if (music->flac_decoder) {
>         init_stage++; /* stage 1! */
>+        flac.FLAC__stream_decoder_set_metadata_respond(music->flac_decoder,
>+                    FLAC__METADATA_TYPE_VORBIS_COMMENT);
> 
>         if (flac.FLAC__stream_decoder_init_stream(
>                     music->flac_decoder,
>@@ -436,6 +544,20 @@ static void *FLAC_CreateFromRW(SDL_RWops *src, int freesrc)
>         return NULL;
>     }
> 
>+    /* loop_start, loop_end and loop_len get set by metadata callback if tags
>+     * are present in metadata.
>+     */
>+
>+    full_length = flac.FLAC__stream_decoder_get_total_samples(music->flac_decoder);
>+    if (((music->loop_start >= 0) || (music->loop_end > 0)) &&
>+        ((music->loop_start < music->loop_end) || (music->loop_end > 0)) &&
>+         (music->loop_start < full_length) &&
>+         (music->loop_end <= full_length)) {
>+        if (music->loop_start < 0) music->loop_start = 0;
>+        if (music->loop_end == 0) music->loop_end = full_length;
>+        music->loop = 1;
>+    }
>+
>     music->freesrc = freesrc;
>     return music;
> }
>@@ -477,6 +599,18 @@ static int FLAC_GetSome(void *context, void *data, int bytes, SDL_bool *done)
>         return -1;
>     }
> 
>+    if (music->loop_flag) {
>+        if (flac.FLAC__stream_decoder_seek_absolute(music->flac_decoder, music->loop_start) ==
>+                FLAC__STREAM_DECODER_SEEK_ERROR) {
>+            SDL_SetError("FLAC__stream_decoder_seek_absolute() failed");
>+            flac.FLAC__stream_decoder_flush(music->flac_decoder);
>+            return -1;
>+        } else {
>+            music->loop_flag = SDL_FALSE;
>+            music->pcm_pos = music->loop_start;
>+        }
>+    }
>+
>     if (flac.FLAC__stream_decoder_get_state(music->flac_decoder) == FLAC__STREAM_DECODER_END_OF_STREAM) {
>         if (music->play_count == 1) {
>             music->play_count = 0;
>@@ -515,6 +649,7 @@ static int FLAC_Seek(void *context, double position)
>         SDL_SetError("Seeking of FLAC stream failed: libFLAC seek failed.");
>         return -1;
>     }
>+    music->pcm_pos = seek_sample;
>     return 0;
> }
>

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Attachments on bug 4855: 4039 | 4040 | 4043 | 4055

We are currently migrating Bugzilla to GitHub issues.Any changes made to the bug tracker now will be lost, so please do not post new bugs or make changes to them.When we're done, all bug URLs will redirect to their equivalent location on the new bug tracker.

We are currently migrating Bugzilla to GitHub issues.
Any changes made to the bug tracker now will be lost, so please do not post new bugs or make changes to them.
When we're done, all bug URLs will redirect to their equivalent location on the new bug tracker.