[FFmpeg-devel] [PATCH]lavf/gsmdec: Add a probe function

[Carl Eugen Hoyos]

Hi!

Attached is a probe function for gsm and a patch for a gsm muxer to allow 
testing. The file format is for example supported by sox.

Please comment, Carl Eugen
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diff --git a/libavformat/gsmdec.c b/libavformat/gsmdec.c
index 97dd8c5..f6fb08e 100644
--- a/libavformat/gsmdec.c
+++ b/libavformat/gsmdec.c
@@ -34,6 +34,23 @@ typedef struct GSMDemuxerContext {
     int sample_rate;
 } GSMDemuxerContext;
 
+static int gsm_probe(AVProbeData *p)
+{
+    int valid = 0, invalid = 1;
+    uint8_t *b = p->buf;
+    while (b < p->buf + p->buf_size - 32) {
+        if ((*b & 0xf0) == 0xd0) {
+            valid++;
+        } else {
+            invalid++;
+        }
+        b += 33;
+    }
+    if (valid >> 5 > invalid)
+        return AVPROBE_SCORE_EXTENSION + 1;
+    return 0;
+}
+
 static int gsm_read_packet(AVFormatContext *s, AVPacket *pkt)
 {
     int ret, size;
@@ -91,6 +108,7 @@ AVInputFormat ff_gsm_demuxer = {
     .name           = "gsm",
     .long_name      = NULL_IF_CONFIG_SMALL("raw GSM"),
     .priv_data_size = sizeof(GSMDemuxerContext),
+    .read_probe     = gsm_probe,
     .read_header    = gsm_read_header,
     .read_packet    = gsm_read_packet,
     .flags          = AVFMT_GENERIC_INDEX,
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diff --git a/libavformat/Makefile b/libavformat/Makefile
index a54e6cb..77b6730 100644
--- a/libavformat/Makefile
+++ b/libavformat/Makefile
@@ -180,6 +180,7 @@ OBJS-$(CONFIG_FSB_DEMUXER)               += fsb.o
 OBJS-$(CONFIG_GIF_MUXER)                 += gif.o
 OBJS-$(CONFIG_GIF_DEMUXER)               += gifdec.o
 OBJS-$(CONFIG_GSM_DEMUXER)               += gsmdec.o
+OBJS-$(CONFIG_GSM_MUXER)                 += rawenc.o
 OBJS-$(CONFIG_GXF_DEMUXER)               += gxf.o
 OBJS-$(CONFIG_GXF_MUXER)                 += gxfenc.o audiointerleave.o
 OBJS-$(CONFIG_G722_DEMUXER)              += g722.o rawdec.o
diff --git a/libavformat/allformats.c b/libavformat/allformats.c
index 94f258d..bb31865 100644
--- a/libavformat/allformats.c
+++ b/libavformat/allformats.c
@@ -136,6 +136,7 @@ void av_register_all(void)
     REGISTER_MUXDEMUX(G722,             g722);
     REGISTER_MUXDEMUX(G723_1,           g723_1);
     REGISTER_DEMUXER (G729,             g729);
+    REGISTER_MUXDEMUX(GSM,              gsm);
     REGISTER_DEMUXER (GENH,             genh);
     REGISTER_MUXDEMUX(GIF,              gif);
     REGISTER_DEMUXER (GSM,              gsm);
diff --git a/libavformat/rawenc.c b/libavformat/rawenc.c
index 358ee4e..14ba9fb 100644
--- a/libavformat/rawenc.c
+++ b/libavformat/rawenc.c
@@ -193,6 +193,20 @@ AVOutputFormat ff_g723_1_muxer = {
 };
 #endif
 
+#if CONFIG_GSM_MUXER
+AVOutputFormat ff_gsm_muxer = {
+    .name              = "gsm",
+    .long_name         = NULL_IF_CONFIG_SMALL("raw GSM"),
+    .mime_type         = "audio/x-gsm",
+    .extensions        = "gsm",
+    .audio_codec       = AV_CODEC_ID_GSM,
+    .video_codec       = AV_CODEC_ID_NONE,
+    .write_header      = force_one_stream,
+    .write_packet      = ff_raw_write_packet,
+    .flags             = AVFMT_NOTIMESTAMPS,
+};
+#endif
+
 #if CONFIG_H261_MUXER
 AVOutputFormat ff_h261_muxer = {
     .name              = "h261",