libgsm: split init and close fuctions for encoder and decoder.

The decoder shouldn't be allocating coded_frame. It's also cleaner to split
them than to check avctx->codec->encode and avctx->codec->decode.

libavcodec/libgsm.c

@@ -35,22 +35,13 @@
 #define GSM_MS_BLOCK_SIZE 65
 #define GSM_FRAME_SIZE 160
 
-static av_cold int libgsm_init(AVCodecContext *avctx) {
+static av_cold int libgsm_encode_init(AVCodecContext *avctx) {
     if (avctx->channels > 1) {
         av_log(avctx, AV_LOG_ERROR, "Mono required for GSM, got %d channels\n",
                avctx->channels);
         return -1;
     }
 
-    if(avctx->codec->decode){
-        if(!avctx->channels)
-            avctx->channels= 1;
-
-        if(!avctx->sample_rate)
-            avctx->sample_rate= 8000;
-
-        avctx->sample_fmt = AV_SAMPLE_FMT_S16;
-    }else{
         if (avctx->sample_rate != 8000) {
             av_log(avctx, AV_LOG_ERROR, "Sample rate 8000Hz required for GSM, got %dHz\n",
                 avctx->sample_rate);
@@ -65,7 +56,6 @@ static av_cold int libgsm_init(AVCodecContext *avctx) {
             if(avctx->strict_std_compliance > FF_COMPLIANCE_UNOFFICIAL)
                 return -1;
         }
-    }
 
     avctx->priv_data = gsm_create();
 
@@ -88,7 +78,7 @@ static av_cold int libgsm_init(AVCodecContext *avctx) {
     return 0;
 }
 
-static av_cold int libgsm_close(AVCodecContext *avctx) {
+static av_cold int libgsm_encode_close(AVCodecContext *avctx) {
     av_freep(&avctx->coded_frame);
     gsm_destroy(avctx->priv_data);
     avctx->priv_data = NULL;
@@ -116,9 +106,9 @@ AVCodec ff_libgsm_encoder = {
     .name           = "libgsm",
     .type           = AVMEDIA_TYPE_AUDIO,
     .id             = CODEC_ID_GSM,
-    .init           = libgsm_init,
+    .init           = libgsm_encode_init,
     .encode         = libgsm_encode_frame,
-    .close          = libgsm_close,
+    .close          = libgsm_encode_close,
     .sample_fmts = (const enum AVSampleFormat[]){AV_SAMPLE_FMT_S16,AV_SAMPLE_FMT_NONE},
     .long_name = NULL_IF_CONFIG_SMALL("libgsm GSM"),
 };
@@ -127,13 +117,52 @@ AVCodec ff_libgsm_ms_encoder = {
     .name           = "libgsm_ms",
     .type           = AVMEDIA_TYPE_AUDIO,
     .id             = CODEC_ID_GSM_MS,
-    .init           = libgsm_init,
+    .init           = libgsm_encode_init,
     .encode         = libgsm_encode_frame,
-    .close          = libgsm_close,
+    .close          = libgsm_encode_close,
     .sample_fmts = (const enum AVSampleFormat[]){AV_SAMPLE_FMT_S16,AV_SAMPLE_FMT_NONE},
     .long_name = NULL_IF_CONFIG_SMALL("libgsm GSM Microsoft variant"),
 };
 
+static av_cold int libgsm_decode_init(AVCodecContext *avctx) {
+    if (avctx->channels > 1) {
+        av_log(avctx, AV_LOG_ERROR, "Mono required for GSM, got %d channels\n",
+               avctx->channels);
+        return -1;
+    }
+
+    if (!avctx->channels)
+        avctx->channels = 1;
+
+    if (!avctx->sample_rate)
+        avctx->sample_rate = 8000;
+
+    avctx->sample_fmt = AV_SAMPLE_FMT_S16;
+
+    avctx->priv_data = gsm_create();
+
+    switch(avctx->codec_id) {
+    case CODEC_ID_GSM:
+        avctx->frame_size  = GSM_FRAME_SIZE;
+        avctx->block_align = GSM_BLOCK_SIZE;
+        break;
+    case CODEC_ID_GSM_MS: {
+        int one = 1;
+        gsm_option(avctx->priv_data, GSM_OPT_WAV49, &one);
+        avctx->frame_size  = 2 * GSM_FRAME_SIZE;
+        avctx->block_align = GSM_MS_BLOCK_SIZE;
+        }
+    }
+
+    return 0;
+}
+
+static av_cold int libgsm_decode_close(AVCodecContext *avctx) {
+    gsm_destroy(avctx->priv_data);
+    avctx->priv_data = NULL;
+    return 0;
+}
+
 static int libgsm_decode_frame(AVCodecContext *avctx,
                                void *data, int *data_size,
                                AVPacket *avpkt) {
@@ -158,8 +187,8 @@ AVCodec ff_libgsm_decoder = {
     .name           = "libgsm",
     .type           = AVMEDIA_TYPE_AUDIO,
     .id             = CODEC_ID_GSM,
-    .init           = libgsm_init,
-    .close          = libgsm_close,
+    .init           = libgsm_decode_init,
+    .close          = libgsm_decode_close,
     .decode         = libgsm_decode_frame,
     .long_name = NULL_IF_CONFIG_SMALL("libgsm GSM"),
 };
@@ -168,8 +197,8 @@ AVCodec ff_libgsm_ms_decoder = {
     .name           = "libgsm_ms",
     .type           = AVMEDIA_TYPE_AUDIO,
     .id             = CODEC_ID_GSM_MS,
-    .init           = libgsm_init,
-    .close          = libgsm_close,
+    .init           = libgsm_decode_init,
+    .close          = libgsm_decode_close,
     .decode         = libgsm_decode_frame,
     .long_name = NULL_IF_CONFIG_SMALL("libgsm GSM Microsoft variant"),
 };