frontend: default to MP4 output with automatic format detection

docs/faac.1

@@ -49,7 +49,6 @@ Input/output options
 .TP
 .BR --help-mp4
 MP4 specific options
-Quality-related options
 .TP
 .BR --help-advanced
 Advanced options, only for testing purposes
@@ -109,10 +108,11 @@ The actual frequency is adjusted to maximize upper spectral band usage.
 .SH INPUT/OUTPUT OPTIONS
 .TP
 .BR -o\ <\fIfilename\fP>
-Set output file to X (only for one input file)
-only for one input file; you can use *.aac, *.mp4, *.m4a or
-*.m4b as file extension, and the file format will be set
-automatically to ADTS or MP4).
+Set output file to X (only for one input file). Format is auto-detected from
+extension (.aac/.adts -> ADTS, .m4a/.mp4/.m4b -> MP4; default: MP4).
+.TP
+.BR -a
+Use ADTS stream output format. Generate ADTS transport stream output.
 .TP
 .BR -
 Use stdin/stdout.
@@ -169,10 +169,6 @@ Ignore wav length from header (useful with files over 4 GB)
 Overwrite existing output file
 .SH MP4 SPECIFIC OPTIONS
 .TP
-.BR -w
-Wrap AAC data in MP4 container. (default for *.mp4, *.m4a and
-*.m4b)
-.TP
 .BR --tag\ <\fItagname,tagvalue\fP>
 Add named tag (iTunes '----')
 .TP

docs/faac.html

@@ -43,9 +43,8 @@ <h3>
 <b>Options:</b><br>
 <menu>
 <li>
-<kbd>-a X</kbd>
-	Set average bitrate to approximately X kbps per channel
-	(i.e. using -a 64 averages at 128 kbps/stereo).
+<kbd>-a</kbd>
+	Use ADTS stream output format.
 <li>
 <kbd>-c &lt;bandwidth&gt;</kbd>
 	Set the bandwidth in Hz (default value depends on sample rate)

frontend/encode_engine.c

@@ -32,6 +32,7 @@
 #include <fcntl.h>
 #else
 #include <sys/time.h>
+#include <unistd.h>
 #endif
 
 #include "encode_engine.h"
@@ -45,6 +46,8 @@ void init_encode_options(encode_options_t *opts)
         return;
 
     memset(opts, 0, sizeof(*opts));
+    opts->container_mp4 = true;
+    opts->stream_format = FAAC_STREAM_ADTS;
     opts->mpeg_version = FAAC_MPEG4;
     opts->object_type = FAAC_OBJ_AUTO;
     opts->joint_mode = FAAC_JOINT_MIXED;
@@ -570,8 +573,12 @@ int run_encoding_session_ext(const encode_options_t *opts,
         else
         {
 #ifdef _WIN32
+            if (!opts->overwrite && win32_access_utf8(opts->output_filename, 0) == 0)
+                FAIL("Output file %s already exists\n", opts->output_filename);
             outfile = win32_fopen_utf8(opts->output_filename, "wb");
 #else
+            if (!opts->overwrite && access(opts->output_filename, 0) == 0)
+                FAIL("Output file %s already exists\n", opts->output_filename);
             outfile = fopen(opts->output_filename, "wb");
 #endif
             if (!outfile)
@@ -616,7 +623,6 @@ int run_encoding_session_ext(const encode_options_t *opts,
     uint32_t current_frame = 0;
     uint64_t total_bytes_written = 0;
     uint64_t current_input_samples = 0;
-    uint64_t encoded_samples = 0;
     uint16_t max_frame_bytes = 0;
     int samples_read = 0;
 
@@ -694,8 +700,6 @@ int run_encoding_session_ext(const encode_options_t *opts,
                 if (!write_output_bytes(outfile, bitbuf, (size_t)bytes_written))
                     FAIL("Output write failed\n");
             }
-
-            encoded_samples += frame_size;
         }
 
         if (progress_cb)

frontend/main.c

@@ -123,9 +123,9 @@ static help_t help_qual[] = {
 
 static help_t help_io[] = {
     {"-o <filename>\tSet output file to X (only for one input file)\n",
-    "\t\tonly for one input file; you can use *.aac, *.mp4, *.m4a or\n"
-    "\t\t*.m4b as file extension, and the file format will be set\n"
-    "\t\tautomatically to ADTS or MP4).\n"},
+    "\t\tFormat is auto-detected from extension (.aac/.adts -> ADTS, .m4a/.mp4/.m4b -> MP4; default: MP4).\n"},
+    {"-a\t\tUse ADTS stream output format.\n",
+    "\t\tGenerate ADTS transport stream output.\n"},
     {"-\t\tUse stdin/stdout\n",
     "\t\tIf you simply use a hyphen/minus sign instead\n"
     "\t\tof a filename, FAAC can encode directly from stdin,\n"
@@ -162,7 +162,6 @@ static help_t help_io[] = {
 };
 
 static help_t help_mp4[] = {
-    {"-w\tWrap AAC data in MP4 container (default for *.mp4, *.m4a and *.m4b)\n", NULL},
     {"--tag <tagname,tagvalue> Add named tag (iTunes '----')\n", NULL},
     {"--artist <name>\tSet artist name\n", NULL},
     {"--artistsort <name>\tSet artist sort order\n", NULL},
@@ -453,6 +452,7 @@ int main(int argc, char *argv[])
 
     char *aacFileName = NULL;
     bool aacFileNameGiven = false;
+    bool stream_flag_given = false;
     bool has_custom_tags = false;
     const char *dieMessage = NULL;
     int ret = 0;
@@ -543,7 +543,7 @@ int main(int argc, char *argv[])
             {"mpeg-version", 1, 0, MPEGVERS_FLAG},
             {"object-type", 1, 0, OBJTYPE_FLAG},
             {"license", 0, 0, 'L'},
-            {"createmp4", 0, 0, 'w'},
+            {"adts", 0, 0, 'a'},
             {"artist", 1, 0, ARTIST_FLAG},
             {"artistsort", 1, 0, ARTIST_SORT_FLAG},
             {"title", 1, 0, TITLE_FLAG},
@@ -572,7 +572,7 @@ int main(int argc, char *argv[])
         };
 
         int option_index = 0;
-        int c = getopt_long(argc, argv, "Hhb:m:o:rnc:q:PR:B:C:I:Xwv:L",
+        int c = getopt_long(argc, argv, "Hhb:m:o:rnc:q:PR:B:C:I:Xv:La",
                             long_options, &option_index);
 
         if (c == -1)
@@ -594,12 +594,19 @@ int main(int argc, char *argv[])
         case 'X':
             opts.raw_endian = false;
             break;
+        case 'a':
+            opts.container_mp4 = false;
+            opts.stream_format = FAAC_STREAM_ADTS;
+            stream_flag_given = true;
+            break;
         case 'o':
             aacFileName = strdup(optarg);
             aacFileNameGiven = true;
             break;
         case 'r':
+            opts.container_mp4 = false;
             opts.stream_format = FAAC_STREAM_RAW;
+            stream_flag_given = true;
             break;
         case 'c':
             opts.bandwidth = atoi(optarg);
@@ -636,9 +643,6 @@ int main(int argc, char *argv[])
             opts.raw_channels = (uint16_t)atoi(optarg);
             opts.raw_pcm_input = true;
             break;
-        case 'w':
-            opts.container_mp4 = true;
-            break;
         case ARTIST_FLAG:
             opts.metadata.artist = optarg;
             break;
@@ -841,9 +845,10 @@ int main(int argc, char *argv[])
     {
         aacFileName = get_output_filename(opts.input_filename, opts.container_mp4);
     }
-    else if (is_mp4_filename(aacFileName))
+    else if (!stream_flag_given)
     {
-        opts.container_mp4 = true;
+        opts.container_mp4 = detect_container_mp4(aacFileName);
+        opts.stream_format = opts.container_mp4 ? FAAC_STREAM_RAW : FAAC_STREAM_ADTS;
     }
 
     if (opts.container_mp4)

frontend/maingui.c

@@ -307,7 +307,7 @@ static DWORD WINAPI EncodeFile(LPVOID pParam)
 
     opts.input_filename = utf8_input;
     opts.output_filename = utf8_output;
-    opts.container_mp4 = utf8_output && is_mp4_filename(utf8_output);
+    opts.container_mp4 = utf8_output && detect_container_mp4(utf8_output);
     opts.overwrite = true;
 
     opts.object_type = (enum faac_object_type)GetComboData(hWnd, IDC_OBJECTTYPE, FAAC_OBJ_AUTO);
@@ -621,12 +621,37 @@ static INT_PTR CALLBACK DialogProc(HWND hWnd, UINT msg, WPARAM wParam, LPARAM lP
         case IDOK:
             if (!Encoding)
             {
+                WCHAR targetOutput[_MAX_PATH];
+                GetDlgItemTextW(hWnd, IDC_OUTPUTFILENAME, targetOutput, _MAX_PATH);
+
+                if (targetOutput[0] != L'\0')
+                {
+                    char *utf8_out = win32_utf16_to_utf8(targetOutput);
+                    if (utf8_out)
+                    {
+                        if (win32_access_utf8(utf8_out, 0) == 0)
+                        {
+                            int msgResult = MessageBoxW(hWnd,
+                                L"The target output file already exists. Do you want to overwrite it?",
+                                L"Confirm Overwrite",
+                                MB_YESNO | MB_ICONQUESTION);
+                            if (msgResult != IDYES)
+                            {
+                                free(utf8_out);
+                                return TRUE;
+                            }
+                            _wremove(targetOutput);
+                        }
+                        free(utf8_out);
+                    }
+                }
+
                 encode_thread_param_t *param = (encode_thread_param_t *)malloc(sizeof(encode_thread_param_t));
                 if (param)
                 {
                     param->hWnd = hWnd;
                     GetDlgItemTextW(hWnd, IDC_INPUTFILENAME, param->inputFilename, _MAX_PATH);
-                    GetDlgItemTextW(hWnd, IDC_OUTPUTFILENAME, param->outputFilename, _MAX_PATH);
+                    wcsncpy(param->outputFilename, targetOutput, _MAX_PATH);
 
                     SendDlgItemMessage(hWnd, IDC_PROGRESS, PBM_SETRANGE, 0, MAKELPARAM(0, GUI_PROGRESS_RANGE));
                     SendDlgItemMessage(hWnd, IDC_PROGRESS, PBM_SETPOS, 0, 0);

frontend/output.c

@@ -60,6 +60,20 @@ char *get_output_filename(const char *input_filename, bool container_mp4)
     return aac_file_name;
 }
 
+bool is_adts_filename(const char *filename)
+{
+    if (!filename)
+        return false;
+
+    const char *ext = find_extension(filename);
+    if (ext)
+    {
+        if (!strcasecmp(ext, ".aac") || !strcasecmp(ext, ".adts"))
+            return true;
+    }
+    return false;
+}
+
 bool is_mp4_filename(const char *filename)
 {
     if (!filename)
@@ -74,6 +88,20 @@ bool is_mp4_filename(const char *filename)
     return false;
 }
 
+bool detect_container_mp4(const char *filename)
+{
+    if (!filename)
+        return true;
+
+    if (!strcmp(filename, "-") || is_adts_filename(filename))
+        return false;
+
+    if (is_mp4_filename(filename))
+        return true;
+
+    return true;
+}
+
 bool check_image_header(const char *buf)
 {
     if (!buf)

frontend/output.h

@@ -27,9 +27,15 @@ extern "C" {
 /* Generate default output filename based on input filename and container type */
 char *get_output_filename(const char *input_filename, bool container_mp4);
 
-/* Check if filename extension suggests MP4 container format */
+/* Check if filename extension suggests ADTS stream format (.aac, .adts) */
+bool is_adts_filename(const char *filename);
+
+/* Check if filename extension suggests MP4 container format (.m4a, .mp4, .m4b) */
 bool is_mp4_filename(const char *filename);
 
+/* Auto-detect whether output file should use MP4 container format based on filename */
+bool detect_container_mp4(const char *filename);
+
 /* Check image header magic bytes (PNG, JPEG, GIF), used to validate
    --cover-art data before it's embedded as an MP4 covr atom. */
 bool check_image_header(const char *buf);